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20130320 Storm Drainage Report 12032013 Larson&Associates Land Surveyors&Engineers, Inc. 4401 South 66th Street Tacoma,WA 98409 STORM DRAINAGE REPORT PROPONENT: Mt. Terrace Builders � Contact: Tony Trunk • � 6524 Cromwell Beach Drive N.W. Gig Harbor, WA. 98335 Ph: (253) 310-5078 '��`��,1 �� M 1�I��I�1 � �-� o�,aWrA�Sf,��<� O ��-'�J -_ ��. �✓�. / � a ` �t � � ��>� �L, / / I,, r , ` � I o . �.:�� .�, ��?.��. � s,; . . �� 0 `5!C�rp� UN ' ♦ ��,� \� `��'� PREPARED BY: Larson & Associates Land Surveyors and Engineers, Inc. 4401 South 66`h Street Tacoma, WA 98409 (253) 474-3404 _ November 13, 2013 �. .f;.-�a.'�..rf.._,.�.f..� 'b a�-'� DECO22013 ��`�: -� r .� � _ �. � �,�, �. PROJECTENGINEER'S CERTIFICATION.........................................................................................................1 DRAINAGE REPORT SECTION1 -PROJECT OVERVIEW .........................................................................................................................2-3 SECTION 2-EXISTING CONDITIONS SUMMARY........................................................................................................3 SECTION 3-OFF-SITE ANALYSIS REPORT.................................................................................................................3 SECTION 4-PERMANENT STORMWATER CONTROL PLAN......................................................................................3-4 SECTION 5-CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN.........................................................5-6 SECTION 6-SPECIAL REPORTS AND STUDIES...........................................................................................................6 SECTION7-OTHER PERMITS...................................................................................................................................6 SECTION 8-OPERATION AND MAINTENANCE MANUAL............................................................................................6 SECTION9-BOND QUANTITIES ...............................................................................................................................6 STORM DRAINAGE CALCULATIONS SUMMARY.................................................................................... 7-19 OPERATION&MAINTENANCE PLAN....................................................................................................... 20-64 APPENDIX........................................................................................................................................................ 65-112 VICINITYMAP ................................................................................................................................................ 66 SITEINFORMATION.................................................................................................................................. 67-69 GEOTECHNICAL REPORT DATED 9/23/13..............................................................................................70-98 FACILITYSUMMARY FORM...................................................................................................................99-I 11 SITEPLAN........................................................................................................................................................112 '�.'� � � , , � I hereby state that this Storm Drainage Report for River Run Apartments has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community for professional engineers. I understand that the City of Yelm does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. I , �- Grant J. Middle on, P.E. , '��`��,, . �� MI nl�j�♦�, e � � . � 1�. � �C��•.�F� 3a o r� �I m I t� � I� ,a � � �v � .O.� �' o 1� �:S,to sA c �C�'=�. �1,`` �� _ , ---� ,� SECTION 1 —PROJECT OVERVIEW The "Yelm Apartments" project is located in the NE1/4 of the SE1/4 of Section 24, Township 17 North, Range 1 East of the Willamette Meridian in the City of Yelm in Thurston County, Washington. The proposal consists of construction of(2) 8 unit apartment buildings for a total of 16 proposed units and associated parking/access and open space areas onsite. The property is approximately 1.14 acres in size located at the site address of 304 Longmire St. on parcel #21724410200. Surrounding properties consist of a golf course to the south and existing Multi-Family complexes. This site will be served by the City of Yelm for water and sanitary sewer. Additional utilities include Puget Sound Energy for power and Qwest Communications for telephone. From looking at Figure 2.2 of Volume I—Minimal Technical Requirements of the 2005 Stormwater Management Manual for Western Washington, since the site does not have 35% or more of existing impervious coverage and the project adds 5,000 square feet or more of new impervious surfaces, all minimum requirements apply to the new impervious surfaces and converted pervious surfaces. These requirements are as follows: Minimum Requirement#l: Preparation of Stormwater Site Plan (This document satisfies this requirement) Minimum Requirement#2: Construction Stormwater Pollution Prevention (SWPPP) (See separate document entitled Construction Stormwater Pollution Prevention Plan) Minimum Requirement#3: Source Control of Pollution (See section of this report entitled Operation & Maintenance Plan which provides information to satisfy this requirement) Minimum Requirement#4: Preservation of Natural Drainage Systems and Outfalls (See Section 4 of this report which discusses how we meet this requirement) Minimum Requirement#5: On-Site Stormwater Management(See Section 4 of this report which discusses how we meet this requirement) Minimum Requirement#6: Runoff Treatment(See Section 4 of this report which discusses how we meet this requirement) Minimum Requirement#7: Flow Control(See Section 4 of this report which discusses how we meet this requirement) Minimum Requirement#8: Wetlands Protection (N/A) Minimum Requirement#9: Basin/Watershed Planning(See Section 4 of this report which discusses how we meet this requirement) Minimum Requirement#10: Operation and Maintenance See section of this report entitled Operation & Maintenance Plan which provides information to satisfy this requirement) 2 All of these requirements will therefore be addressed throughout this report and on the attached Civil Engineering Site Development Plans. SEC'TIQN 2 - EXISTING CONDITIONS SUMMARY The site is located east of the intersection of Longmire St. SE and Berry valley Dr. The project area is currently vacant land and sloping from southwest to northeast. A high point is situated in the northwest corner at an approximate elevation of 345. The site then slopes to the northeast to an approximate low point elevation of 340 along the northeastern property boundary line. The site is presently covered in trees and prairie grasses/brush. Stormwater runoff presently sheet flows across the site from the southwest to the northeast and is infiltrated through the "good" onsite soils located across the site. Per the S.C.S. soils map, on-site soils consist of Spanaway gravelly sandy loam which will very conducive to infiltration of stormwater for proposed improvements onsite. Pacific Geo Engineering, LLC performed an onsite soil investigation on August 6, 2013 at(9) test pit locations onsite to approximate depth of 11 feet and performed field percolation testing at(3) of these (9)total test pit locations. It was determined from there testing that an"in field" infiltration rate of 12 in/hr exists onsite within the native soils. We have taken this information and applied a factor of safety of(2) for a design infiltration rate for onsite infiltration trench facilities of 6 in/hr which we utilized for our Final Stormwater Quantity Control design. SECTION 3 —OFF-SITE ANALYSIS REPORT 100% onsite infiltration is proposed for all runoff generated from proposed onsite impervious and pervious surfaces so no downstream effects are anticipated from this proposal. Note that applicable onsite construction stormwater BMPs will be employed to ensure that downstream properties will not be detrimentally effected in any way from this proposaL SECTION 4—PERMANENT STORMWATER CONTROL PLAN SUB-SECTION 1 —EXISTING SITE HYDROLOGY As previously discussed, the site is located east of the intersection of Longmire St. SE and Berry valley Dr. The project area is currently vacant land and sloping from southwest to northeast. A high point is situated in the northwest corner at an approximate elevation of 345. The site then slopes to the northeast to an approximate low point elevation of 340 along the northeastern property boundary line. The site is presently covered in trees and prairie grasses/brush. Stormwater runoff presently sheet flows across the site from the southwest to the northeast and is infiltrated through the "good" free draining soils located across the site. � SUB-SECTION 2—DEVELOPED SITE HYDROLOGY All roof runoff will be collected and infiltrated directly into the ground by individual building infiltration trenches, since it is considered"clean" per Department of Ecology standards. Stormwater runoff from all disturbed pervious and impervious on-site surfaces, including all driveways, sidewalks, parking areas, park area and landscape islands will be collected via catch basins and routed by a tightlined conveyance system, sized for the 25-year/24 hour developed storm event, to and through an"Aqua Swirl" basin for treatment of stormwater prior to release to a propertly sized infiltration trench for release to groundwater. The infiltration trench systems have been sized to meet volume requirements from the MGS FLOOD continuous runoff model. Since 100% on- site retention is being proposed, it is not necessary to analyze a downstream course. Below are Predeveloped & Developed Site Areas utilized for stormwater quality & quantity control facility design in the MGS FLOOD modeling program: Pre-develoqed Site Areas (ONSITE): Total Site Area: 0.435 AC. Total Pervious Area: 0.435 AC. (Modeled as "Outwash Forest" in MGS FLOOD program) Developed Site Areas (ONSITE): Total Site Area: 0.435 AC. Total Impervious Surface Area: 0.435 AC.* (*includes parking/access, extruded curb & sidewalk) SUB-SECTION 3—PERFORMANCE STANDARDS AND GOALS Due to our proposal triggering formal stormwater quality and quantity control requirements per the 2005 Department of Ecology Stormwater manual, we have proposed an"Aqua Swirl" treatment basin for treatment of stormwater runoff from proposed pollution generating impervious surfaces (PGIS) (i.e.parking lot runof�. Treated stormwater will then be routed to an adequately sized infiltration trench for stormwater quantity control purposes meeting City of Yelm and DOE requirements. SUB-SECTION 4—FLOW CONTROL SYSTEM As previously discussed, flow control will be achieved by utilizing infiltration trench systems throughout the site for contributing building and parking area runof£ As previously mentioned, we have utilized a design infiltration rate of 6 inlhr for Flow Control Infiltration Facility design due to findings by the geotechnical engineer(Pacific Geo Engineering, LLC). See attached MGS Flood calculations within this report for all pertinent storm trench sizing calculations. SUB-SECTION 5—WATER QUALITY SYSTEM As previously mentioned, an"Aqua Swirl"basin will be utilized to provide water quality for runoff generated from proposed pollution generating impervious surfaces onsite (PGIS) prior to release to the appropriately sized infiltration trench for release of treated runoff to groundwater. � SUB-SECTION 6—CONVEYANCE SYSTEM ANALYSIS AND DESIGN The conveyance system has been sized to accommodate the 25-year/24 hour developed storm event as determined from the MGS FLOOD continuous runoff model (15 min. time step). SECTION 5—CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN During the construction of this project, standard erosion control methods such as a temporary construction entrance and mirafi siltation fences will be utilized to trap sediment from the cleared areas. A construction entrance will be installed at the entrance to the project to keep sediment from being tracked out of the site and onto the City roads. Mirafi silt fences will be installed along all low areas to stop any sediment runoff from leaving the site. These erosion control measures should be inspected as a minimum on a weekly basis except during winter conditions or major storm events. During these cases, the temporary erosion control measures should be inspected on a daily basis and sedimentation build up removed as necessary to maintain a properly functioning system. Should the temporary erosion and sedimentation control measures as shown on the approved plans not prove adequate to control erosion and sedimentation, the applicant/contractor shall install additional facilities as necessary to protect adjacent properties, sensitive areas, natural water courses, and/or storm drainage systems. Permanent erosion control will consist of hydroseeding and/or sod, landscaping, and paving. A certified ESC lead shall be available to monitor and report to the City of Yelm on an ongoing basis during construction until the final inspection of all improvements has been completed. The construction sequence for this project should be followed as shown below. CONSTRUCTION SEQUENCE 1. Call City of Yelm inspector for pre-construction meeting. 2. Clearly flag all limits of clearing and grading per approved plans. 3. Install temporary construction entrance. 4. Install temporary mirafi filter fences. 5. Remove existing structures as indicated on the T.E.S.C. plan. �Acquire appropriate demolition permits from City of Yelm. 6. Construct temporary sediment/storm ponds per design on this sheet. 7. Clear and grade site per approved plans. � 8. Any vegetation or other materials taken off site shall be hauled to a City Approved dump site. 9. Install utilities (i.e. sanitary, water, etc.) 10. Construct paved driveway and storm drain system per approved plans. 11. Provide C.B. protection until road and storm drain system is completed and all exposed slopes are seeded and stabilized for erosion and sedimentation. 12. Note: The building contractor is responsible for maintenance of storm system during building and landscape construction. 13. Hydroseed and/or mulch slopes and other exposed areas immediately after grading is completed as outlined in"erosion control notes". 14. Clean out and test all storm drain facilities. 15. Inspect and maintain all erosion control facilities at regular intervals and complete required report. Clean as required until risk of sedimentation has passed. 16. Until all projects which produce surface runoff are completed and all exposed ground surfaces are stabilized by vegetation or landscaping, permanent storm facilities may not be operated and no surface runoff may be permitted to enter the permanent storm system. SECTION 6—SPECIAL REPORTS AND STUDIES All special reports and/or studies, including a geotechnical report,that will be necessary for the development of this site will be included with the final engineering submittal. SECTION 7—OTHER PERMITS Applicable permits that will need to be applied include (but are not limited to)the following: Building permit ROW permit Clearing/Grading permit Sewer and Water permit Site Development permit SECTION 8—OPERATION AND MAINTENANCE MANUAL See section of this report entitled"Operation and Maintenance Plan." SECTION 9—BOND QUANTITIES WORKSHEET This will be completed and submitted to the City of Yelm for Approval at the appropriate time. �o STORM DRAINAGE CALCULATIONS SUMMARY LARSON AND ASSOCIATES, INC. LAND SURVEYORS & ENGINEERS 4401 SOUTH 66TH STREET TACOMA, WA 98409 � M •t V v`�� '�-bn'� V��T�'f�1 QU�Q l�T�"`C' � , e a 3 � ,: y�,E�� '� /��a r .s �v�, � � E ; � g� �A;�j� � r" %� °�i �� : 3 . ! d�� ` r f�€ J � a t." �,,. � . .,K,�,, .'�.�., „ ,,,,, , �t'�x. ,;,. •, �;r�.��, „'� ;�,�;.. ��. w.,. �r� �r �/ � „�.,>. , <;<;„ ,.,, ,,:. .; a,: ;.,. ,,, '.,<_�. ,�,. . .. .. . C°py Prink... ' Image , . _ 1, ti. ,4!faker Quaht�Q.ata flow Splitter Calculator _ _ _ _ __ _ _ _ _ . � Compute Water Q�ualit��Treatment Valume for Link Computed Basic Wek Pond Volume,91%Exceedance(cu-fkJ: Nok Computed Compuked Large Wef Pond Volume(Phosphorous ConkrolJ,1.5"Basic Volume(cu-ftJ: Not Computed Time ko Infiltrate 91%Treatment Valume,(Applies ko Infiltration Facilitiesj Nvt Campuked .. ; Gompute InfiltratianjFil#retion Statistics Total Runofi Volume 174.45 ac-f Percent Treaked (Infiltrated+FilteredjlTokal 100.00° Total Runoff Infiltrated 174.45 ac-it 100:00° Total RunoffFiltered 0.00 ac-fk D,00° �H;Gompute 2�rr Discharge Rate for Link Outflow �cfs� Nok Cornpu�ed w; ;Compute W�#er Qualiiy 15-Minute Design Discharge for Link Inflaw , On-Line Facility Design Discharge Rate(cfsj: 0.061 y� ' Off-Line Faciliry Design Discharge fiate(cfsJ: 0.035 �-- �S�1' �.�..,v . _ _. �w _ t , aase ' [ � ��I��R�A�l,cx� ��u�-N �zCt� �rz. MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: 11/13/2013 3:36 PM Input File Name: Yelm Apartments Infiltration Trench.fid Project Name: Yelm Apartments Analysis Title: infiltration Trench Sizing Comments: PRECIPITATION INPUT Computational Time Step (Minutes): 60 Extended Precipitation Timeseries Selected Climatic Region Number: 13 Full Period of Record Available used for Routing Precipitation Station : 96004005 Puget East 40 in 5min 10/01/1939-10/01/2097 Evaporation Station : 961040 Puget East 40 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default *"*"****** Default HSPF Parameters Used (Not Modified by User) *""*"""*"*'"'*** '`*"**"**"`**"**********WATERSHED DEFINITION *******""*"**********"'` ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ----------Subbasin : Subbasin 1 ---------- ' -------Area(Acres) -------- Till Forest � 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.435 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 0.000 Impervious 0.000 ---------------------------------------------- Subbasin Total 0.435 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ----------Subbasin : Subbasin 1 ---------- -------Area(Acres) -------- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.000 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 4 Green Roof 0.000 � User 0.000 Impervious 0.435 ---------------------------------------------- Subbasin Total 0.435 ***********�************* LINK DATA****��***************,�********* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ****�******************** LINK DATA�****************************** ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: New Infilt Trench Lnk1 Link Type: Infiltration Trench Downstream Link: None Trench Type � Toe of Embankment Trench Length (ft) : 55.00 Trench Width (ft) : 10.00 Trench Depth (ft) : 4.00 Trench Bottom Elev(ft) : 100.00 Trench Rockfill Porosity(%) : 30.00 Constant Infiltration Option Used Infiltration Rate (in/hr): 6.00 *"**'`**'`**************FLOOD FREQUENCY AND DURATION STATISTICS**'"**************** ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 *******"**"Water Quality Facility Data************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 *""******" Link: New tnfilt Trench Lnk1 ******`*** Infiltration/Filtration Statistics-------------------- Total Runoff Vofume(ac-ft): 192.11 Total Runoff Infiltrated (ac-ft): 192.11, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% �0 **"********Compliance Point Results'`"*********** Scenario Predeveloped Compliance Subbasin: Subbasin 1 Scenario Postdeveloped Compliance Link: New Infilt Trench Lnk1 **" Point of Compliance Flow Frequency Data*** Recurrence Intervai Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr(Years) Discharge (cfs) Tr(Years) Discharge(cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 8.536E-05 2-Year 3.817E-06 5-Year 8.714E-05 5-Year 7.630E-06 10-Year 8.759E-05 10-Year 1.083E-05 25-Year 2.029E-04 25-Year 1.606E-05 50-Year 4.025E-04 50-Year 1.866E-05 100-Year 6.226E-04 100-Year 0.024 200-Year 1.120E-03 200-Year 0.045 "* Record too Short to Compute Peak Discharge for These Recurrence Intervals *""* Flow Duration Performance According to Dept. of Ecology Criteria**"`* Excursion at Predeveloped YzQ2 (Must be Less Than 0%): -99.9% PASS Maximum Excursion from 'hQ2 to Q2 (Must be Less Than 0%): -99999.0% PASS Maximum Excursion from Q2 to'Q50 (Must be less than 10°/o): -62.0% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS . • ------------------------------------------------------------------------------------------------- POND MEETS ALL DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- II ��.lG-1 Si.?�.� FatZ. '6o-rN ��5� C��l�sP MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: 11/12/2013 9:21 AM Input File Name: Yelm Apartments BLDG. trench.fld Project Name: Yelm Apartments Analysis Title: Building Infiltration Trench (both buildings to trench) Comments: PRECIPITATION INPUT Computational Time Step (Minutes): 60 Extended Precipitation Timeseries Selected Climatic Region Number: 14 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in 5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP �F� Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default *****"*"** Default HSPF Parameters Used (Not Modified by User) ***"*"**""***** **********************WATERSHED DEFINITION *******'`*********'`***** ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ----------Subbasin : Subbasin 1 ---------- -------Area(Acres) -------- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.174 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 0.000 Impervious 0.000 ---------------------------------------------- Subbasin Total 0.174 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin : Subbasin 1 ---------- -------Area(Acres) -------- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.000 Outwash Pasture 0.000 Outwash Grass 0.000 wetland 0.000 12 Green Roof 0.000 User 0.000 Impervious 0.174 ---------------------------------------------- Subbasin Total 0.174 ************************* LINK DATA******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA****�**************,�*********** ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: New Infiit Trench Lnk1 Link Type: Infiltration Trench Downstream Link: None Trench Type � Trench at Toe of Embankment Trench Length (ft) 40.00 Trench Width (ft) 6.00 Trench Depth (ft) 4.00 Trench Bottom Elev (ft) : 100.00 Trench Rockfill Porosity(%) : 30.00 Constant Infiltration Option Used Infiltration Rate (in/hr): 6.00 `*******'`**"****'`*****FLOOD FREQUENCY AND DURATION STATISTICS******"************ ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 *"*********Water Quality Facility Data************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 **'`******* Link: New Infilt Trench Lnk1 *�******** Infiltration/Filtration Statistics-------------------- Total Runoff Volume (ac-ft): 86.06 Total Runoff Infiltrated (ac-ft): 86.06, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% t3 *******"***Compliance Point Results *******'"***** Scenario Predeveloped Compliance Subbasin: Subbasin 1 Scenario Postdeveloped Compliance Link: New Infilt Trench Lnk1 *** Point of Compliance Flow Frequency Data*** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr(Years) Discharge (cfs) Tr(Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 3.457E-05 2-Year 2.656E-06 5-Year 3.504E-05 5-Year 5.494E-06 10-Year 9.381 E-05 10-Year 7.723E-06 25-Year 3.632E-04 25-Year 1.145E-05 50-Year 8.479E-04 50-Year 1.326E-05 100-Year 9.605E-04 100-Year 1.476E-05 200-Year 1.842E-03 200-Year 1.680E-05 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance According to Dept. of Ecology Criteria*"** Excursion at Predeveloped '/ZQ2 (Must be Less Than 0%): 0.0% PASS Maximum Excursion from '/ZQ2 to Q2 (Must be Less Than 0%): 0.0% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 0.0% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS --------------------------------------------------------`--------------------------------------- POND MEETS ALL DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- l'� �u�`i�-c2�-rso�t -�-az�.►-�-+ s�z�� r-a,e. 'PA r2�C�r b �1 R�c�, MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: 11/13/2013 3:46 PM Input File Name: Yelm Apartments Covered Parking Trench.fld Project Name: Yelm Apartments Analysis Title: Covered Parking Infiltration Trench Comments: PRECIPITATION INPUT Computational Time Step (Minutes): 60 Extended Precipitation Timeseries Selected Climatic Region Number: 14 Full Period of Record Available used for Routing Precipitation Station : 96004405 Puget East 44 in 5min 10/01/1939-10/01/2097 Evaporation Station : 961044 Puget East 44 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default *'`****"""" Default HSPF Parameters Used (Not Modified by User) ''*****"******** "***"*"**""********'`**WATERSHED DEFINITION *********************** ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ----------Subbasin : Subbasin 1 ---------- -------Area(Acres)-------- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.055 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 0.000 Impervious 0.000 ---------------------------------------------- Subbasin Total 0.055 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ----------Subbasin : Subbasin 1 ---------- -------Area(Acres) -------- Till Forest 0.000 Till Pasture 0.000 Till Grass 0.000 Outwash Forest 0.000 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland o.000 � .rJ Green Roof 0.000 User 0.000 Impervious 0.055 ---------------------------------------------- Subbasin Total 0.055 �***�**********�*�******* LINK DATA***«�**********�*************** ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ***�********************* LINK DATA******************.�*********** ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: New Infilt Trench Lnk1 Link Type: Infiltration Trench Downstream Link: None Trench Type � rench at T e of Embankment Trench Length (ft) 20.00 Trench Width (ft) 3.00 Trench Depth (ft) 3.00 Trench Bottom E►ev (ft) : 100.00 Trench Rockfill Porosity (%) : 30.00 Constant Infiltration Option Used Infiltration Rate(in/hr): 6.00 '`********"********"***FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 **'"****'*"*Water Quality Facility Data*****"*"***** ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 *******"** Link: New Infilt Trench Lnk1 ""******"� Infiltration/Filtration Statistics-------------------- Total Runoff Volume (ac-ft): 27.20 Total Runoff Infiltrated (ac-ft): 27.20, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00°/a Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% ICO *****"****"Compliance Point Results************* Scenario Predeveloped Compliance Subbasin: Subbasin 1 Scenario Postdeveloped Compliance Link: New Infilt Trench Lnk1 *** Point of Compliance Flow Frequency Data*** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr(Years) Discharge (cfs) Tr(Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 1.093E-05 2-Year 3.748E-06 5-Year 1.108E-05 5-Year 6.267E-06 10-Year 2.965E-05 10-Year 8.140E-06 25-Year 1.148E-04 25-Year 1.119E-05 50-Year 2.680E-04 50-Year 1.308E-05 100-Year 3.036E-04 100-Year 1.323E-05 200-Year 5.824E-04 200-Year 4.626E-03 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **"` Flow Duration Performance According to Dept. of Ecology Criteria **** Excursion at Predeveloped '/ZQ2 (Must be Less Than 0%): -98.8% PASS Maximum Excursion from '/ZQ2 to Q2 (Must be Less Than 0%): -99999.0% PASS Maximum Excursion from Q2 to Q50 (Must be'less than 10%): -80.0% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): �0.0% PASS µ . � �� POND MEETS ALL DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- �� CB #6 (FLOW SPLITTER STRUCTURE) Worksheet for Circular Channel Project Description Worksheet FLOW SPLITTEF Flow Element Circular Channel Method Manning's Formu Solve For Channel Depth Input Data Mannings Coeffic).013 Slope 0.57 % Diameter 12 in / Discharge 0.04 cfs $--..r Q�r�,.�E 'F�,(�=T�( '(J'C��( �rj yuZ�,j,� �.oW1��1�1(�rJ �AO�7 u W1�7�"C�IJ(� �bC�iZ.P�M Results Depth 0.0� 8 ft � Flow Area 3.1 e-2 ft2 Wetted Perime 0.58 ft Top Width 0.55 ft Criticai Depth 0.08 ft Percent Full 8.3 % Critical Slope 0.70 % Velocity 1.22 ft/s Velocity Head 0.02 ft Specific Energ� 0.11 ft Froude Numbe 0.91 Maximum Disc 2.89 cfs Discharge Full 2.69 cfs Slope Full 1.14e-4 % Flow Type 3ubcritical Project Engineer:Jeff Cederholm untitled.fm2 Larson&Associates FlowMaster v6.1 [614k] 11/22/13 02:14:24 PM O Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA (203)755-1666 Page 1 of 1 �a 12" Storm Pipe @ 0.50%(min.) (100YR Storm - 15 min. time step) Worksheet for Circular Channel Project Description Worksheet 12"STORM PIPE P Flow Element Circular Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coeffic).013 Slope 0.50 % Diameter 12 in Discharge 0.44 cfs Results Depth 0.28 ft Flow Area � 0.2 ftz Wetted Perime 1.12 ft Top Width 0.90 ft Critical Depth 0.27 ft Percent Full 28.3 % Critical Slope 0.56 % Velocity 2.41 ft/s Velocity Head 0.09 ft Specific Energ� 0.37 ft Froude Numbe 0.94 Maximum Disc 2.71 cfs Discharge Full 2.52 cfs Slope Full 0.02 % Flow Type 3ubcritical _ _ _..., __ Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr(Years) Discharge(cfs) Tr(Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 3.363E-04 2-Year 0.162 5-Year 3.471 E-04 5-Year 0.211 10-Year 3.493E-04 10-Year 0.237 25-Year 3.584E-04 25-Year 0.298 50-Year 4.694E-04 50-Year 0.380 100-Year 7.475E-04 100-Year 0.439 �'' "'TY�3� 200-Year 9.446E-04 200-Year .a'455" [Od�� ToRWI �5��• �7 F�R. C.o►.av�`�{A►.1c.E, . ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ,�� Project Engineer:Jeff Cederholm untitled.fm2 Larson 8�Associates FlowMaster v6.1 [614k] 11/22/13 04:39:22 PM O Haestad Methods, inc. 37 Brookside Road Waterbury, CT 06708 USA (203)755-1666 Page 1 of 1 �`i �pER.ATION AND MAINTENANCE PLAN LARSON & ASSOCIATES LAND SUI2VEYORS & ENGINEERS, INC. 4401 S. 66TH STREET TACOMA, WA. 98409 Zo ATTACHEMENT "A" Description of River Run Apartments Storm Draina�e Svstem. All roof runoff will be collected and infiltrated directly into the ground by individual building infiltration trenches, since it is considered "clean" per Department of Ecology standards. Stormwater runoff from all disturbed pervious and impervious on-site surfaces, including all driveways, sidewalks,parking areas, park area and landscape islands will be collected via catch basins and routed by a tightlined conveyance system, sized for the 25-year/24 hour developed storm event, to and through an"Aqua Swirl" basin for treatment of stormwater prior to release to a propertly sized infiltration trench for release to groundwater. The infiltration trench systems have been sized to meet volume requirements from the MGS FLOOD continuous runoff model. Since 100% on-site retention is being proposed, it is not necessary to analyze a downstream course. MAINTENANCE RESPONSIBILITY 1.) Responsible party for maintenance of the storm drainage system: Mt. Terrace Builders Contact: Tony Trunk 6524 Cromwell Beach Drive N.W. Gig Harbor, WA. 98335 Ph: (253) 310-5078 The estimated annual cost for maintenance of the storm drainage system as identified in Attachment"A" is $1000.00 per year. 2.l MAINTENANCE PROGRAM COVER SHEET FOR CITY OF YELM Inspection Period: Number of Sheets Attached: Date Inspected: Name of Inspector: Inspector's Signature: INSTRUCTIONS FOR USE OF MAINTENANCE CHECKLISTS The following pages contain maintenance needs for most of the components that are part of your drainage system, as well as for some components that you may not have. Let the City know if there are any components that are missing from these pages. Ignore the requirements that do not apply to your system. You should plan to complete a checklist for all system components on the following schedule: (1) Monthly from November through April (2) Once in late summer (preferable September) (3) After any major storm (use 1-inch in 24 hours as a guideline), items marked "S" only. Using photocopies of these pages, check off the problems you looked for each time you did an inspection. Add comments on problems found and actions taken. Keep these "checked" sheets in your files, as they will be used to write your annual report. Some items do not need to be looked at every time an inspection is done. Use the suggested frequency at the left of each item as a guideline for your inspection. ZZ No. 2—Infiltration Maintenance Defect Conditions When Maintenance Is Results Expected When Component Needed Maintenance Is Performed General Trash &Debris See"Detention Ponds" (No. 1). See"Detention Ponds" (No. 1). Poisonous/Noxious See"Detention Ponds"(No. 1). See"Detention Ponds" Vegetation (No. 1). Contaminants and See"Detention Ponds"(No. 1). See"Detention Ponds" Pollution (No. 1). Rodent Holes See"Detention Ponds"(No. 1). See"Detention Ponds" (No. 1) Storage Area Sediment Water ponding in infiltration pond after Sediment is removed rainfall ceases and appropriate time and/or facility is cleaned allowed for infiltration. so that infiltration system works according to (A percolation test pit or test of facility design. indicates facility is only working at 90%of its designed capabilities. If two inches or more sediment is present, remove). Filter Bags(if Filled with Sediment and debris fill bag more than 1/2 Filter bag is replaced or applicable) Sediment and full. system is redesigned. Debris Rock Filters Sediment and By visual inspection, little or no water flows Gravel in rock filter is Debris through filter during heavy rain storms. replaced. Side Slopes of Erosion See"Detention Ponds"(No. 1). See"Detention Ponds" Pond (No. 1). Emergency Tree Growth See"Detention Ponds"(No. 1). See"Detention Ponds" Overflow Spillway (No. 1). and Berms over 4 feet in height. Piping See"Detention Ponds"(No. 1). See"Detention Ponds" (No. 1). Emergency Rock Missing See"Detention Ponds"(No. 1). See"Detention Ponds" OverFlow Spillway (No. 1). Erosion See"Detention Ponds"(No. 1). See"Detention Ponds" (No. 1). Pre-settling Facility or sump 6"or designed sediment trap depth of Sediment is removed. Ponds and Vaults filled with Sediment sediment. and/or debris February 2005 Vo/ume V—Runoff Treatment BMPs 4-33 Z3 No. 5—Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash& Trash or debris which is located immediately No Trash or debris located Debris in front of the catch basin opening or is immediately in front of blocking inletting capacity of the basin by catch basin or on grate more than 10%. opening. Trash or debris(in the basin)that exceeds 60 No trash or debris in the percent of the sump depth as measured from catch basin. the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free blocking more than 1/3 of its height. of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present within or dangerous gases(e.g., methane). the catch basin. Sediment Sediment(in the basin)that exceeds 60 No sediment in the catch percent of the sump depth as measured from basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Top slab has holes larger than 2 square Top slab is free of holes Damage to inches or cracks wider than 1/4 inch and cracks. Frame and/or Top Slab (Intent is to make sure no material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on separation of more than 3/4 inch of the frame the riser rings or top slab from the top slab. Frame not securely and firmly attached. attached Fractures or Maintenance person judges that structure is Basin replaced or repaired Cracks in unsound. to design standards. Basin Walls/ Bottom Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inleUoutlet pipe or any evidence of soil particles entering catch basin through cracks. SettlemenU If failure of basin has created a safety, Basin replaced or repaired Misalignment function, or design problem. to design standards. Vegetation Vegetation growing across and blocking more No vegetation blocking than 10%of the basin opening. opening to basin. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present. six inches apart. 4-36 Volume V—Runoff Treatment BMPs February 2005 2�f No. 5—Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed Contamination See"Detention Ponds"(No. 1). No pollution present. and Poliution Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is Cover Place Any open catch basin requires maintenance. ciosed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. Bolts proper tools. Not Working into frame have less than 1/2 inch of thread. Cover Difficult One maintenance person cannot remove lid Cover can be removed by to Remove after applying normal lifting pressure. one maintenance person. (Intent is keep cover from sealing off access to maintenance.) Ladder Ladder Rungs Ladder is unsafe due to missing rungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Trash and debris that is blocking more than Grate free of trash and Debris 20%of grate surface inletting capacity. debris. Damaged or Grate missing or broken member(s)of the Grate is in place and Missing. grate. meets design standards. No. 6—Debris Barriers (e.g., Trash Racks) Maintenance Defect Condition When Maintenance is Results Expected When Components Needed Maintenance is Pertormed General Trash and Trash or debris that is plugging more Barrier cleared to design flow Debris than 20%of the openings in the barrier. capacity. Metal Damaged/ Bars are bent out of shape more than 3 Bars in place with no bends more Missing inches. than 3/4 inch. Bars. Bars are missing or entire barrier Bars in place according to design. missing. Bars are loose and rust is causing 50% Barrier replaced or repaired to deterioration to any part of barrier. design standards. InIeUOutlet Debris barrier missing or not attached to Barrier firmly attached to pipe Pipe pipe February 2005 Vo/ume V—Runoff Treatment BMPs 4-37 �� No. 18-Catchbasin Inserts Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed General Sediment When sediment forms a cap over the No sediment cap on the insert Accumulation insert media of the insert and/or unit. media and its unit. Trash and Trash and debris accumulates on insert Trash and debris removed Debris unit creating a blockage/restriction. from insert unit. Runoff freely Accumulation flows into catch basin. Media lnsert Not Effluent water from media insert has a Effluent water from media Removing Oil visible sheen. insert is free of oils and has no visible sheen. Media lnsert Catch basin insert is saturated with water Remove and replace media Water Saturated and no longer has the capacity to insert absorb. Media lnsert-Oil Media oil saturated due to petroleum spill Remove and replace media Saturated that drains into catch basin. insert. Media lnsert Use Media has been used beyond the typical Remove and replace media at Beyond Normal average life of inedia insert product. regular intervals, depending on Product Life insert product. 4-50 Volume V—Runoff Treatment BMPs February 2005 � � �TClRM�1VA`f"ER TREATMEN�" SC3LUTIC3R�� Aqua-SwirITM Stormwater Treatment System Inspection and Maintenance Manual AquaShield,T"'Inc. 2705 Kanasita Drive, Chattanooga,TN 37343 Phone: (423)870-8888 Fax: (423) 826-2112 Email: info@aquashieldinc.com Z*7 Table of Contents Introduction / Operation / Maintenance • Introduction to AquaShieldT'" Stormwater Treatment Systems • Operation of the Aqua-SwirITM Stormwater Treatment System • Inspection & Maintenance of the Aqua-SwirITM System • Appendix Inspection & Maintenance Data Sheet 2705 Kanasita Drive, Chattanooga, Tennessee 37343 Phone (888) 344-9044, Fax (423) 870-2112 www.aquashieldinc.com 2� AquaShieldT"', Inc .� Stormwater Treatment Solutions The highest priority of AquaShieldTM, Inc. (AquaShieldTM) is to protect waterways by providing stormwater treatment solutions to businesses across the world. These solutions have a reliable foundation based on over 20 years of water treatment experience. Local regulators, engineers, and contractors have praised the AquaShieldT'" systems for their simple design and ease of installation. All the systems are fabricated from durable, lightweight materials, and contractors prefer the quick and simple installation of our structures that saves them money. The AquaShieldT'" line of patented stormwater treatment products provide for high levels of stormwater treatment: � The Aqua-Swir/""Stormwate� TreatmentSystem is a hydrodynamic separator, which provides a highly effective means for the removal of TSS (fine to coarse sediment), floating debris and free-oil. • The Aqua-Fi/terT"'StormwaterFi/tration System is an treatment train stormwater filtration system capable of gross contaminant removal, and the removal of fine sediments, waterborne hydrocarbons, heavy metals (i.e. zinc) and nutrients such as phosphorous and nitrogen. s- - w `� flV�� 3�° � �� f , �.� ��5��s �Nj�. Vl 'Y"� �3 ��ik,�� `6r,��/r ,P y'j '. ��i�• Gfsl�Yti �Mfu:�� y��I �4��. �I`lil;+ a,, �..+.w��.";�w...». ..-«�:�� Aqua-Swirl'""Stormwater Aqua-Filter'"' Stormwater Treatment System Filtration System �� A ua-SwirITM Stormw q ater Treatment � Syste m The patented Aqua-SwirlT'"Stormwater Treatment System is a hydrodynamic separator, which provides a highly effective means for the removal of sediment, free oil, and floating debris. Independent university laboratory performance evaluations have shown that the Aqua-SwirlT'"achieves a TSS removal of 91% calculated on a net annual basis. The Aqua-Swirlr"; with a conveyance flow diversion system, allows simple installation by connecting "directly"to the existing storm conveyance pipe. This connection provides full treatment of the °first flush,"while the peak design storm is diverted and channeled through the main conveyance pipe. �� ti ��; .� ,,� ,�F �,,,::. , ... �,;u � �. �� a,�.., :,� , ��, � , �..� � ; � �a �� v �_ �.,.;� � E ' � � � � ��` �¢^e�� : fi � �..t,� y �,� � �� : �� .�� °� ; ' � � , �' y; � }� °� � ;;�-,.�,€ r��r�� " � �.��-€��.,. �:; ,;,,,„� �,, ��. �' ��:»„ �� a�� N_f,,,,�' °"�i,p,. ,,.. .� .. . , :�p.y;r,.. .:� �.,m 3 ,,rfi;; :..;:.9 1 i'% � �...� ,��. .. . .. ... �- � ...._. : . . � . � :��,. � � Aqua-SwirITM -� Stormwater Treatment System The patented Aqua-SwirlT'" Stormwater Treatment System %._,,'k.�F provides a highly effective means for �� ;'- the removal of sediment, floating debris, and free oil. Swirl technology, or vortex separation, is a proven form of treatment utilized in the stormwater industry to accelerate gravitationa) separation. Independent university laboratory performance evaluations have shown the Aqua-Swir1T'" achieves a TSS (Total Suspended Solids) removal of 91% calculated on a net annual basis. See the "Performance ��'e,,. _��* and Testing"Section for more �� "��`�"�� details. Each Aqua-SwirlT'" is constructed of lightweight and durable materials, eliminating the need for heavy lifting equipment during installation. Inspection and maintenance are made easy, with oversized risers that allow for both examination and cleanout without entering the chamber. �� -� _System Operation The Aqua-SwirlT'", with a conveyance flow diversion system, provides full treatment for the most contaminated "first flush", while the cleaner peak storm flow is diverted and channeled through the main conveyance pipe. Many regulatory agencies are in the process of establishing "water quality treatment flow rates"for specific areas based on the initial migration of pollutants into the storm drainage system. 31 The treatment operation begins � �� "�'�„°a'��'r,��'�""` '„"�°a��, � ��` "' r y��!�IIP�i��I�I�IW� �-., I p�l� ,, � � ` when stormwater enters the � � ; ';�'' � � .�� § Aqua-SwirITM through a � " �� x `� : tangential inlet pipe that '�� ' �`g �F � N ,�� ^� �'S� produces a circular (or vortex) ��` � � '�4��" �� . flow pattern that causes � � f�� >� ��,�� , , contaminates to settle to the f�� :� s �. base of the unit. Since ` � ��F ��`""� � � �. stormwater flow is intermittent ' _ ;,�r by nature, the Aqua-SwirITM `` . � �� retains water between storm �; �� events providing both ��dynamic �' ''�� and quiescent" settling of solids. �� y` � The dynamic settling occurs ��'� ��., p �� during each storm event while � Floatable debris in the Aqua-SwirlT"' the quiescent settling takes place between successive storms. A combination of gravitational and hydrodynamic drag forces encourages the solids to drop out of the flow and migrate to the center of the chamber where velocities are the lowest, as shown from extensive CFD modeling. See "Performance and Testing"for more details. A large percentage of - settleable solids in t,z-�9s�.,� � � �� ,� �, stormwater are re orted to be small ' �� p v� � �� , :. and have low settling � ,��; '��% �� velocities. Therefore, � � X� �� r �� .. �� ' the volume of water � � �° �� . ;��" �� retained in the Aqua- �� ,�k,�� _ � SwirITM provides the � � � � �` �� uiescent settlin that ` ' � q 9 �. � ��. ;��, ' increases performance. '° � '" � , � � ,° r� x�,. Furthermore, due to = finer sediment adhering � � � �� onto larger particles �� ' (less than 200 microns), ' � �sz� � ;r the larger particles ��►��,�;�� settle, rather than � �' ° staying suspended in ��°�" ��°�ti��: ��F��. .� ' the water. ,. r, ,,, ,�. , .._� 32. The treated flow then exits the Aqua-SwiriT'" behind the arched outer bafFie. The top of the baffle is sealed across the treatment channel, thereby eliminating floatable pollutants from escaping the system. A vent pipe is extended up the riser to expose the backside of the bafFle to atmospheric conditions, preventing a siphon from forming at the bottom of the baffle. As recommended by the Center for Watershed Protection and several municipalities, the Aqua-SwirITM can also operate in an ofFline configuration providing full treatment of the '�first flush." However, this orientation requires the installation of additional manhole structures to diverge the flow to the Aqua- Swir1T"" for treatment and conveyance back to the existing main conveyance storm drainage system. �� .� Custom Applications � � The Aqua-SwirITM system can be ,��A, � `�fi,: °"'� ; modified to fit a variety of purposes � ;�.; � in the field, and the angles for inlet � �� and outlet lines can be modified to t ��,,, ; fit most applications. The photo on g � °� � ` �.� _ � the left demonstrates the flexibility � ,�i�, � s' ��"� `� ' "��q � of Aqua-SwirITM installations. Two ��. �'��'� A ua-Swirlr'" units were laced side . � �� q P � �� `�� b side in order to treat a hi h � g # ,.. � Y �� volume of water while occupying a �- ��:. � � , ��°' � small amount of space. This � configuration is an example of the �;�� ` many ways AquaShieldT"' can use '' „�,W�,�,,�,a�� ; � " �� ' ,� � our roducts to ada t to a varie of y,,,�.,,<..ti,�,,.. „ �v,M,� ,,,,, �,,,�w,..�_. ,�„� P P tY Custom designed AS-9 Twin,Aqua-Swirl�" applications. �- Retrofit Applications The Aqua-SwirITM system is designed so that it can easily be used for retrofit applications. With the invert of the inlet and outlet pipe at the same elevation, the Aqua-SwirITM can easily be connected directly to the existing storm conveyance drainage system. Furthermore, because of the lightweight nature and small footprint of the Aqua-SwirlT'", existing infrastructure utilities (i.e., wires, poles, trees) would be unaffected by installation. 33� � ' AquaShieldTM Product =� System Maintenance The long-term performance of the stormwater treatment �i s,,...d,. structures (including ° p �� 9 manufactured systems, ;� , .,�,,; , . � ponds, swales, etc.), and the � � �� '�,� r� � - �-a, xe � ,- effective protection of �F ;� _ � .�, , receiving waters, depends on � �� "� ,� w a consistent maintenance � ��„ �� ''��,�'k ��;;, m`,i�" ��. �, �-�� plan. Inspection and "_' "�' �' maintenance functions are � ' simple and easy for the AquaShieldT'" Stormwater ' ��, ., Treatment Systems allowing � YN ��,� �, � 1� all inspections to be �� _;�� Q � �� performed from the surface. An AquaShieldTM field representative will be available as needed to assist local maintenance personnel in the field. Please contact us for a copy of a product-specific��Inspection and Maintenance Manual". It is important that a routine inspection and maintenance program be established for each unit based on (1) the volume or load of the contaminants of concern, (2) the frequency of releases of contaminants at the facility or location, and (3) the nature of the area being drained. In order to ensure that our systems are being ��°� maintained properly, "" �� , AquaShieldTM offers a � _ ' ' � � ��; .� maintenance solution ��`��`�� `� �`� ` � � � ,� � � �� ' . ...:......��,Y t � to all of our customers. '4 �� a ,�,�� , ,� tv,,�. We will arrange to � t��, ��9� , _� ��' have maintenance �� ° '� � � �,.;� „ � �' �� , . perFormed. �� '�� `` �� ,� � �„ '�� ; ,,�,� � t � B� �� z y�,'i:, . ��'�33.. 4t e, ^1., tu ik G8 � � -..- Inspection All AquaShieldTM products can be inspected from the surface, eliminating the need to enter the systems to determine when cleanout should be performed. In most cases, AquaShieldT'" recommends a quarterly inspection of the Stormwater Treatment Systems for the first year of operation to develop an appropriate schedule of maintenance. Based on experience of the system's first year in operation, we recommend that the inspection schedule be revised to reflect the site-specific conditions encountered. Typically, the inspection schedule for subsequent years is reduced to semi-annual inspection. �� TM �,.- Aqua-Swirl Ma�ntenance The Aqua-SwirITM has been designed to minimize and simplify the inspection and maintenance process. The system can be inspected and maintained completely from the surface, thereby eliminating the need for confined space entry. Furthermore, the entire structure (specifically, the floor) is accessible for visual inspection from the surface. There are no areas of the structure that are blocked from visual inspection or periodic cleaning. Inspection of any free-floating oil and floatable debris can be directly observed and maintained through the manhole access provided directly over the swirl chamber. Aqua-SwirITM Inspection Procedure s °� ��,:.; �w -�� X �% To inspect the Aqua-SwirlT'", a hook is needed to remove ' ° � '' �. . ;;, the manhole cover. AquaShieldT'" provides a customized manhole cover with our logo to make it easy for � �"� maintenance crews to locate the system in the field. We f also provide a permanent metal information plate attached - inside the access riser, which provides our contact � � information, the Aqua-SwirlT"' model size, and serial � ;�.. number. � „�.�,,,n,,.�,.�,.��,,q�,,yr�,.,�_,,,._�. . �r � � Sedimentinspection using a stadia rod 35 The only tools needed to inspect the Aqua- SwirITM system are a flashlight and a measuring device such as a stadia rod or pole. Given the tremendous accessibility provided, floating oil and debris can be observed directly from the surface. Sediment depths can easily be determined by lowering a measuring device to the top of the sediment pile and to the surface of the water. When the sediment pile is within 30 �:. to 36 inches of the water surface, the system ` should be maintained. � s� �� , ' �.�� E�. � � � It should be noted that in order to avoid � � � `��£ underestimating the volume of sediment in the chamber, the measuring device must be 5 �� "� � carefully lowered to the top of the sediment �"'� � pile. The finer sediment at the top of the pile, typically offers less resistance to the measuring device than the larger particles. Aqua-SwirlT"" Cleanout Procedure Clean out of the Aqua-SwirlT"' is simple. Free-floating oil � ' � W and floatable debris can be observed and removed directly � ° ' through the 30-inch service access provided. y ` � � � � N�� A vacuum truck can be used to remove the accumulated � �� r� sediment and debris. It is important to note that the entire �� :-��' � �'` � w `� _ � �� sediment storage area can be reached with a vacuum �� hose from the surface (reaching all the sides). � � ��° � � �'�� .�..,,..,. . �.�._:� .��, �.�,»�� Disposal of the material is typically treated in the same Vacuum truck cleans the fashion as catch basin cleanouts. AquaShieldTM Aqua-Swirl�M recommends that all materials removed be handled and disposed of in accordance with local and state requirements. Inspection Data Sheets are provided in the Appendix of this Manual. 3� APPENDIX 3�7 Aqua-SwirlT"' Inspection and Maintenance Manual for BMP Owners (Note: Attach certifications for local regulatory aufhority including any applicable fees.) ' Si#e and Owner Information Site Name: Change in ownership since last inspection Y N Owner Name: Owner Address: Owner Phone Number: Emergency Phone Number: Location: Date: Time: Inspector Name: 'Maintenance item�s lnspection Floatable Debris and Oil 1.Remove manhole lid to expose liquid surface of Aqua-SwirlT"' 2.Remove floatable debris with basket or net if any present. 3.if oil is present,measure its depth. Clean liquids from system if 1/2"or more oil is present(see"Cleaning"Figure 5). Note: Water in an Aqua-SwiriT""can appear black like oil due to the dark body of the surrounding structure. Oil appears darker than water in the system and is usually accompanied by debris(e.g.Styrofoam,etc.)with obvious signs of oil stains. The depth of oil can be measured with an oil/water interface probe,a stadia rod with water phylic paste, a coliwasa,or by simply collecting a representative sample with a jar attached to a rod. Sediment Accumulation Make measurements as follows(see Figures 1 and 2): 1. Lower measuring device(i.e.stadia rod)into Aqua-SwirlT""throught service access provided. (See Figure 2) 2. Record distance to top fo sediment pile(in): 3. Record distance to top of water(in): ,�,�,F„ k z G 4. Calculate distance to sediment minus distance to water(in): �� n� 5. Schedule cleanin rf value in ste 4 is 30"or less. See Fi ure 3. �� 9� P � 9 ) � �� t i��'. �y�,.T�' � .._� : �- 39' � ,� Figure 1 Figure 2 Aqua-SwirlT"'I and M Manual Page 1 � :lnspection(continued) Diversion Structures If a diversion structure is present on the site,this should be inspected for the following items. 1. Inspect weir or other structure for structural decay or damage. Weirs are more susceptible to damage than off-set piping and shouid be checked to confirm that they are not crumbling,in the case of concrete or brick weirs,or decaying if a steel weir was used. 2.Inspect diversion structure and by-pass piping for signs of structural damage or blockage from debris or sediment accumulation. 3.Measure elevations on diversion weir or piping to ensure it is consistent with site plan design. 4.Inspect downstream structure in diversion system for signs of blockage or structural failure. Cieaning �, Schedule cleaning with local vactor company or AquaShieldT"''s Maintenance Department to remove sediments,oils,and other floatable pollutants with a vactor trailer. The captured sediment generally does not require any special treatment or handling for disposal. AquaShield recommends that all materials removed during the maintenance process be handled and disposed of in accordance with local and state requirements. .�.� � � �' �� : �5, �� z ` i� ' � .�� a-��. � �a��,�x�"«*: � ,�: �� 3 �;��,, ��"�x� � � �� k. �Y��'�,� �'`:: Figure 3 - Maintenance Schedule During Construction _ Inspect the Aqua-SwirlT""every three months and clean the system as needed. The Aqua-SwirlT"" should be inspected and cleaned at the end of construction regardless of whether it has reached its sediment or oil storage capacity. First Year Post-Construction Inspect the Aqua-SwirlT^"every three months and clean the system as needed. Inspect and clean the system once annually regardless of whether it has reached its sediment or floatable pollutant storage capacity. Second and Subsequent Years Post-Construction If the Aqua-SwirITM did not reach full sediment or floatable pollutant capacity in the First Year Post-Construction,the system can be inspected and cleaned once annually. If the Aqua-SwirlT"'reached full sediment or floatable pollutant capacity in less than 12 months in the First Year Post-Construction,the system shouid be inspected once every six months and cleaned as needed.The Aqua-SwirlT"' should be cleaned annually regardless of whether it reaches its sediment or floatable pollutant capacity. Bypass Structures Bypass structures should be inspected whenever the Aqua-SwirlT""is inspected and maintained as needed. Aqua-SwirlT""i and M Manual Page 2 3�i � ' Maintenance Company lnformation Company Name: Street Address: City,State,Zip: Contact: �,.�° �� O�ce Phone: �-- .a�. ; ' � � � 5 < � � ` S Mobile Phone: � �` z �� ;��.;'.:~. Pager: ;�k� �: , . ,,,,x'�. Acti�ity Log , Date of cleaning: (Next inspection should be 3 months from this date for the first year). Time of cleaning: Date of next inspection: Floatable debris present(Y/N)? Oil present(Y/N)? Oil depth(inches): Structural Conditions and Comments Any structural damage? Y N Where? Any evidence of structural wear? Y N Where? Odors present? Y N Describe: Any plugging? Y N Describe: Aqua-SwirlT""1 and M Manual Page 3 yo NOTES Additional Comments and/or Actions to Be Taken Time Frame NOTES: 1.Attach site plan showing Aqua-SwiriT'" location. 2.Attach detail drawing showing Aqua-SwirlT"" dimensions and model number. 3. If a diversion structure is used,attach details showing basic design and elevations. Aqua-SwirlT""I and M Manual Page 4 yl Aqua-Swirl T"' ' TABULAR MAINTENANCE SCHEDULE Date Construction Started: Date Construction Ended: During Construction Month ACtivity 1 2 3 4 5 6 7 8 9 10 11 12 Inspecland Clean as X X X X Needed Inspect Bypass Structures (if applicable)and Maintain X X X X As Needed Clean System' X* *The Aqua-SwirlT""should be cleaned once a year regardless of whether it has reached full pollutant storage capacity. In addition,the system should be cleaned at the end of construction regardless of whether it has reach full pollutant storage capacity. 'First Year Post-Construction Month Activity 1 2 3 4 5 6 7 8 9 10 11 12 Inspectand Clean as X X X X Needed Inspect Bypass Structures (if applicable)and Maintain X X X X As Needed Clean System' X* *The Aqua-SwirlT""should be cleaned once a year regardless of whether it has reached full pollutant storage capacity. Second and Subsequent Years Post-CQnstruction Month Activity 1 2 3 4 5 6 7 8 9 10 11 12 Inspect and Clean as Xe Needed` Inspect Bypass Structures (if applicable)and Maintain X" As Needed Clean System* X* *If the Aqua-SwirlT""did not reach full sediment or floatable pollutant capacity in the First Year Post-Construction,the system can be inspected and cleaned once annually. If the Aqua-SwirlT^' reached full sediment or floatable pollutant capacity in less than 12 months in the First Year Post-Construction,the system should be inspected once every six months(more frequently if past history warrants)and cleaned as needed.The Aqua-SwirlT"" should be cleaned annually regardless of whether it reaches its sediment or floatable pollutant capacity. Aqua-SwirlT"'1 and M Manual Page 5 yZ ATTACHMENT "B" INSTRUCTIONS FOR THE OWNER/S OF "RIVER RUN APARTMENTS" POLLUTION SOURCE CONTROLS The attached material includes information on pollution source controls. Pollution source controls are actions taken by a person or person representing a business to reduce the amount of pollution reaching surface and ground waters. Pollution source controls also called"best management practices" (BMP's) include: Altering the activity (e.g., substitute not-toxic products or recycle) Enclosing or covering the activity. Segregating the activity (e.g. diverting surface water runoff away from an area that is contaminated.) Pollution source controls are needed because of the contamination found in surface water runoff from commercial areas and the effect of this contamination on aquatic life and human health. Research on urban runoff in the Puget Sound area and elsewhere has found oil and grease, nutrients, organic substances, toxic metals, bacteria, viruses, and sediments at unacceptable levels. Effects of contaminate runoff include closure of shellfish harvesting areas and swimming areas, pollution of welis, mortality of young fish and other aquatic organisms, tumors on fish, and impairment of fish reproduction. The RIVER RtJN APARTMENTS project contains impervious surfaces that will collect contaminates from automobiles & garbage,. These materials are conveyed to the storm drainage systems and will enter into the surface water, if not treated properly. Attachment"B" contains a number of BMP's for various uses within the development site. The owner shall give a copy of the BMP's suitable to this or her respective activity. If a certain activity is not contained in Attachment"B",please contact Larson and Associates at 253-474- 3404 for a specific BMP activity type. �13 REQUIRED ACTIONS OF OWNER The following actions shall be taken by all owners to ensure that pollution generated on the Norwood Property is minimized. 1) Warning signs (e.g. "Dump no waste—drains to Stream") shall be stenciled or embossed adjacent to all catch basin inlets. They shall be repainted once a year or more as necessary. The planning and Land Services Dept. of Pierce County can be contacted regarding availability of stencils. 2) Paved roadways shall be swept twice a year. It is recommended that newer high- velocity vacuum sweeper be used. 3) The storm drainage system shall be maintained per Attachment "A" 4) No activities shall be conducted on the property that is likely to result in a short-term high concentration discharge of pollution to the storm system. Such activities shall include, but are not limited to car washes, vehicle maintenance, and cleaning of equipment and or vehicles, unless the project has been properly permitted for such uses and the BMP's for such uses have been received by the owner. 5) Automobile fluids, chemicals etc. shall be disposed of legally and properly. 6) All garbage shall be contained in appropriate containers. �� 4.3 BMPs TO CONSIDER FOR ALL ACTIVITIES This is a summary of items that each business/homeowner should consider. As stated before, most of these are common sense, housekeeping types of solutions, but if each business/homeowner would take some action on each of these,the improvement in water quality would be substantial. 1. Avoid the activity or reduce its occurrence If you can, avoid the activity or do it less frequently. If there a substitute process or a different material you can use to get the job done? Can you do a larger run of a process at one time,thus reducing the number of times per week or month it needs to be repeated? For instance,raw materials could be delivered close to the time of use instead of being stockpiled and exposed to the weather. Perhaps you could avoid one solvent-washing step altogether. The Department of Ecology or the Tacoma-Pierce County Health Department can provide pollution prevention assistance. 2. Move the activity indoors Sometimes it is fairly easy to move an activity indoors out of the weather. The benefits of this are twofold;you prevent runoff contamination, and you provide for easier, more controlled cleanup if a spill occurs. An example would be unloading and storing barrels of chemicals inside a garage area instead of doing it outside. Please be aware that moving storage areas indoors may require installation of fire suppression equipment or other building modifications as required by the Uniform Building Code,the Uniform Fire Code, or local ordinances. 3. Use less material Don't buy or use more material than you really need. This not only helps keep potential disposal, storage and pollution problems to a minimum, but will probably save you money,too. 4. Use the least toxic materials available Investigate the use of materials that are less toxic than what you use now. Perhaps a causic-type detergent or a solvent could be replaced with a more environmentally friendly product. Such a change might allow you to discharge process water to the sanitary sewer instead of paying for expensive disposal. Remember that even if you do switch to a biodegradable product, nothing but uncontaminated water is allowed to enter the storm drain system. 5. Create and maintain vegetated areas near activity locations Vegetation of various kinds can help filter pollutants out of stormwater, so it is advisable to route stormwater through vegetated areas located near your activity. For instance, many parking lots contain grassy islands,typically formed in a"hump". By creating those islands as depressions instead of humps, they can be used to treat runoff from the parking lot or roo£ Also, don't forget the erosion control benefits of vegetation at your site. �� 6. Locate activities as far as possible from surface drainage paths Activities located as far as possible from known drainage paths,ditches, streams, and drains will be less likely to pollute, since it will take longer for material to reach the drainage feature. This gives you more time to react in the event of a spill, or if it is a"housekeeping" issue may protect the local waters long enough for you to clean up the area around the activity. Don't forget that groundwater issues are always prominent,no matter where the activity is located so the actions taken on your site on a day-to-day basis are always important,even in dry weather. 7. Keep storm drain systems clean Pollutants can concentrate over time in storm drainage structures such as catch basins, ditches and storm drains. When a large storm event occurs, it can mobilize these pollutants and carry them to receiving waters. Develop and implement maintenance practices, inspections, and schedules for treatment devices (e.g., detention ponds,oil/water separators,vegetated swales,etc.). Requirements for cleaning catch basins will be discussed later in the specific BMP 5.9. 8. Reduce, reuse and recycle as much as possible Always look for ways to recycle instead of just disposing. This can save money as well as keep both hazardous and non-hazardous materials out of the landfills. You can learn more about other businesses that have made process changes allowing recycling of chemicals by calling the DOE at 1-800- RECYCLE and requesting publication#9245 and 90-22. Another unique recycling opportunity for businesses is available through the"matchmaker", helping one company's waste become another company's asset. For instance,waste peach pits from a cannery become potpourri ingredients to anothers business. Call IMEX at 206-625-623 to list your potentially usable solid or chemcial waste in their publication. 9. Be an advocate for stormwater pollution prevention Help friends,partners and business associates find ways to reduce stormwater pollution in their activities. Most people want clean water, and do not pollute intentionally. Share your ideas and the BMPs in this manual to get them thinking about how their everyday activities affect water quality. 10. Report Violators Allowing anyone to pollute our waters is wrong. We all must do our part to protect water, fish,wildlife and our own health, by employing proper BMPs, and reporting those who are causing pollution. y� STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5.10 BMPS FOR SMALL PARCELS A Small Parcel Stormwater Management Plan must be developed which satisfies the Small Parcel Minimum Requirements found in Volume II, Chapter II-2. These in turn may be satisfied by employing a suitable selection from the following list of BMPs. BMP ES.10 PLANNED CLEARING AND GRADING Plan and implementation proper clearing and grading of the site. It is most important only to clear the areas needed,thus keeping exposed areas to a minimum. Phase clearing so that only those areas that are actively being worked are uncovered. Note: Clearin�? limits should be flag�ed in the lot or area prior to initiating clearing, BMP ES.20 EXCAVATING BASEMENT SOIL Located excavated basement soil a reasonable distance behind the curb, such as in the backyard or side yard area. This will increase the distance eroded soil must travel to reach the storm sewer system. Soil piles should be covered until the soil is either used or removed. Piles should be situated so that sediment does not run into the street or adjoining yards. BMP ES.30 BACKFILLING Backfill basement walls as soon as possible and rou�h grade the lot. This will eliminate large soil mounds which are highly erodible and prepares the lot for temporary cover which will further reduce erosion potential. BMP ES.40 REMOVAL OF EXCESS SOIL Remove excess soil from the site as soon as possible after backfilling. This will eliminate any sediment loss from surplus fill. BMP ES.50 MANAGEMENT OF SOIL BANKS If a lot has a soil bank higher than the curb, a trench or berm should be installed moving the bank several feet behind the curb. This will reduce the occurrence of gully and hill erosion while providing a storage and settling area for stormwater. BMP ES.60 CONSTRUCTION ROAD ACCESS Apply gravel or crushed rock to the driveway area and restrict truck traffic to this one route. Driveway paving can be installed directly over the gravel. This measure will eliminate soil from adhering to tires and stops soil from washing into the street. This measure requires periodic inspection and maintenance including washing,top-dressing with additional stone, reworking and compaction. (For further details see BMP E2.10, Chapter II-5.7.1). 4? BMP ES.70 SOIL STABILIZATION Stabilized denuded areas of the site by mulching, seeding, planting, or sodding. For further details on standards and specifications, see BMPs No. E1.10,E1.15, E1.35, E1.40 in Chapter II-5. BMP ES.80 STREET CLEANING Provide for periodic street cleaning to remove any sediment that may have been tracked out. Sediment should be removed by shoveling or sweeping and carefully removed to a suitable disposal area where it will not be re-eroded. II-5.11 References (1) Goldman, Steven J., Erosion and Sediment Control Handbook, McGraw-Hill, 1986. (2) Horner,Richard R.,Juno Guedry and Michael H. Kortenhof,Highway Construction Site Erosion and Pollution Control Manual, Washington State Department of Transportation with the United States Department of Transportation Federal Highway Administration, WA-RD 200.2,January, 1990. (3) Metro, Summarv of Preliminary Data Analysis—BMP Survey of Sin�le Family Residential Construction Sites, January, 1984. (4) Brandy,Nile C., The Nature and Properties of Soils, Eight Edition, MacMillan, 1974. �$ BMPs for Dust Description of Pollutant Sources: Dust can cause air and water pollution Control at problems particularly at demolition sites and in arid areas where reduced Disturbed Land rainfall exposes soil particles to transport by air. Areas and Unpaved Pollutant Control Approach: Minimize dust generation and apply Roadways and environmentally friendly and government approved dust suppressant Parking Lots chemicals, if necessary. Applicable Operational BMPs: • Sprinkle or wet down soil or dust with water as long as it does not result in a wastewater discharge. • Use only local and/or state government approved dust suppressant chemicals such as those listed in Ecology Publication#96-433, "Techniques for Dust Prevention and Suppression." • Avoid excessive and repeated applications of dust suppressant chemicals. Time the application of dust suppressants to avoid or minimize their wash-off by rainfall or human activity such as irrigation. • Apply stormwater containment to prevent the conveyance of stormwater TSS into storm drains or receiving waters. • The use of motor oil for dust control is prohibited. Care should be taken when using lignin derivatives and other high BOD chemicals in excavations or areas easily accessible to surface water or ground water. • Consult with the Ecology Regional Office in your area on discharge permit requirements if the dust suppression process results in a wastewater discharge to the ground, ground water, storm drain, or surface water. Recommended Additional Operational BMPs for Roadways and Other Trafficked Areas: • Consider limiting use of off-road recreational vehicles on dust generating land. • Consider paving unpaved permanent roads and other trafficked areas at municipal, commercial, and industrial areas. • Consider paving or stabilizing shoulders of paved roads with gravel, vegetation, or local government approved chemicals. • Encourage use of alternate paved routes, if available. • Vacuum or wet sweep fine dirt and skid control materials from paved roads soon after winter weather ends or when needed. • Consider using traction sand that is pre-washed to reduce dust emissions. 2-96 Vo/ume /V- Source Control BMPs February 2005 `t9 Additional Recommended Operational BMPs for Dust Generating Areas: • Prepare a dust control plan. Helpful references include: Control of Open Fugitive Dust Sources (EPA-450/3-88-088), and Fugitive Dust Background Document and Technical Information Document for Best Available Control Measures (EPA-450/2-92-004) • Limit exposure of soil (dust source) as much as feasible. • Stabilize dust-generating soil by growing and maintaining vegetation, mulching, topsoiling, and/or applying stone, sand, or gravel. • Apply windbreaks in the soil such as trees, board fences, tarp curtains, bales of hay, etc. • Cover dust-generating piles with wind-impervious fabric, or equivalent material. February 2005 Volume IV- Source Control BMPs 2-17 5a BMPs for Description of Pollutant Sources: Landscaping can include grading, soil Landscaping transfer, vegetation removal, pesticide and fertilizer applications, and and Lawn/ watering. Stormwater contaminants include toxic organic compounds, Vegetation heavy metals, oils,total suspended solids, coliform bacteria, fertilizers, and Management pesticides. Lawn and vegetation management can include control of objectionable weeds, insects, mold, bacteria and other pests with chemical pesticides and is conducted commercially at commercial, industrial, and residential sites. Examples include weed control on golf course lawns, access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs; rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential lawn/plant care. Toxic pesticides such as pentachlorophenol, carbamates, and organometallics can be released to the environment by leaching and dripping from treated parts, container leaks, product misuse, and outside storage of pesticide contaminated materials and equipment. Poor management of the vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater contamination. Pollutant Control Approach: Control of fertilizer and pesticide applications, soil erosion, and site debris to prevent contamination of stormwater. Develop and implement an Integrated Pest Management Plan(IPM) and use pesticides only as a last resort. If pesticides/herbicides are used they must be carefully applied in accordance with label instructions on U.S. Environmental Protection Agency (EPA) registered materials. Maintain appropriate vegetation, with proper fertilizer application where practicable, to control erosion and the discharge of stormwater pollutants. Where practicable grow plant species appropriate for the site, or adjust the soil properties of the subject site to grow desired plant species. Applicable Operational BMPs for Landscaping: • Install engineered soil/landscape systems to improve the infiltration and regulation of stormwater in landscaped areas. • Do not dispose of collected vegetation into waterways or storm drainage systems. Recommended Additional Operational BMPs for Landscaping: � Conduct mulch-mowing whenever practicable • Dispose of grass clippings, leaves, sticks, or other collected vegetation, by composting, if feasible. February 2005 Vo/ume IV- Source Control BMPs 2-23 5t • Use mulch or other erosion control measures when soils are exposed for more than one week during the dry season or two days during the rainy season. • If oil or other chemicals are handled, store and maintain appropriate oil and chemical spill cleanup materials in readily accessible locations. Ensure that employees are familiar with proper spill cleanup procedures. • Till fertilizers into the soil rather than dumping or broadcasting onto the surface. Determine the proper fertilizer application for the types of soil and vegetation encountered. • Till a topsoil mix or composted organic material into the soil to create a well-mixed transition layer that encourages deeper root systems and drought-resistant plants. • Use manual and/or mechanical methods of vegetation removal rather than applying herbicides, where practical. Applicable Operational BMPs for the Use of Pesticides: • Develop and implement an IPM (See section on IPM at end of BMP) and use pesticides only as a last resort. • Implement a pesticide-use plan and include at a minimum: a list of selected pesticides and their specific uses; brands, formulations, application methods and quantities to be used; equipment use and maintenance procedures; safety, storage, and disposal methods; and monitoring, record keeping, and public notice procedures. All procedures shall conform to the requirements of Chapter 17.21 RCW and Chapter 16-228 WAC (Appendix IV-D R.7). • Choose the least toxic pesticide available that is capable of reducing ' the infestation to acceptable levels. The pesticide should readily degrade in the environment and/or have properties that strongly bind it to the soil. Any pest control used should be conducted at the life stage when the pest is most vulnerable. For example, if it is necessary to use a Bacillus thurin�iens is application to control tent caterpillars, it must be applied before the caterpillars cocoon or it will be ineffective. Any method used should be site-specific and not used wholesale over a wide area. • Apply the pesticide according to label directions. Under no conditions shall pesticides be applied in quantities that exceed manufacturer's instructions. • Mix the pesticides and clean the application equipment in an area where accidental spills will not enter surface or ground waters, and will not contaminate the soil. 2-24 Volume IV- Source Control BMPs February 2005 52 • Store pesticides in enclosed areas or in covered impervious containment. Ensure that pesticide contaminated stormwater or spills/leaks of pesticides are not discharged to starm drains. Do not hose down the paved areas to a storm drain or conveyance ditch. Store and maintain appropriate spill cleanup materials in a location known to all near the storage area. • Clean up any spilled pesticides and ensure that the pesticide contaminated waste materials are kept in designated covered and contained areas. • The pesticide application equipment must be capable of immediate shutoff in the event of an emergency. • Do not spray pesticides within 100 feet of open waters including wetlands, ponds, and streams, sloughs and any drainage ditch or channel that leads to open water except when approved by Ecology or the local jurisdiction. All sensitive areas including wells, creeks and wetlands must be flagged prior to spraying. • As required by the local government or by Ecology, complete public posting of the area to be sprayed prior to the application. • Spray applications should only be conducted during weather conditions as specified in the label direction and applicable local and state regulations. Do not apply during rain or immediately before expected rain. Recommended Additional Operational BMPs for the use of pesticides: • Consider alternatives to the use of pesticides such as covering or harvesting weeds, substitute vegetative growth, and manual weed control/moss removal. • Consider the use of soil amendments, such as compost,that are known to control some common diseases in plants, such as Pythium root rot, ashy stem blight, and parasitic nematodes. The following are three possible mechanisms for disease control by compost addition(USEPA Publication 530-F-9-044): 1. Successful competition for nutrients by antibiotic production; 2. Successful predation against pathogens by beneficial microorganism; and 3. Activation of disease-resistant genes in plants by composts. Installing an amended soil/landscape system can preserve both the plant system and the soil system more effectively. This type of approach provides a soil/landscape system with adequate depth,permeability, and organic matter to sustain itself and continue working as an effective stormwater infiltration system and a sustainable nutrient cycle. February 2005 Vo/ume /V- Source Control BMPs 2-25 �� • Once a pesticide is applied, its effectiveness should be evaluated for possible improvement. Records should be kept showing the applicability and inapplicability of the pesticides considered. • An annual evaluation procedure should be developed including a review of the effectiveness of pesticide applications, impact on buffers and sensitive areas (including potable wells), public concerns, and recent toxicological information on pesticides used/proposed for use. If individual or public potable wells are located in the proximity of commercial pesticide applications contact the regional Ecology hydrogeologist to determine if additional pesticide application control measures are necessary. • Rinseate from equipment cleaning and/or triple-rinsing of pesticide containers should be used as product or recycled into product. • The application equipment used should be capable of immediate shutoff in the event of an emergency. For more information, contact the WSU Extension Home-Assist Program, (253) 445-4556, or Bio-Integral Resource Center (BIRC), P.O. Box 7414, Berkeley, CA.94707, or the Washington Department of Ecology to obtain "Hazardous Waste Pesticides" (Publication #89-41); and/or EPA to obtain a publication entitled "Suspended, Canceled and Restricted Pesticides" which lists all restricted pesticides and the specific uses that are allowed. Valuable information from these sources may also be available on the internet. Applicable Operational BMPs for Vegetation Management: • Use at least an eight-inch "topsoil" layer with at least 8 percent organic matter to provide a sufficient vegetation-growing medium. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can substantially improve the permeability of the soil, the disease and drought resistance of the vegetation, and reduce fertilizer demand. This reduces the demand for fertilizers, herbicides, and pesticides. Organic matter is the least water-soluble form of nutrients that can be added to the soil. Composted organic matter generally releases only between 2 and 10 percent of its total nitrogen annually, and this release corresponds closely to the plant growth cycle. If natural plant debris and mulch are returned to the soil, this system can continue recycling nutrients indefinitely. • Select the appropriate turfgrass mixture for your climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endophytic fungi found naturally in their tissues repel or kill common leaf and stem-eating lawn insects. They do not, however, repel root-feeding lawn pests such as Crane Fly larvae, and are toxic to ruminants such as cattle and sheep. The fungus causes no known 2-26 Volume IV- Source Control BMPs February 2005 54 adverse effects to the host plant or to humans. Endophytic grasses are commercially available and can be used in areas such as parks or golf courses where grazing does not occur. The local Cooperative Extension office can offer advice on which types of grass are best suited to the area and soil type. • Use the following seeding and planting BMPs, or equivalent BMPs to obtain information on grass mixtures, temporary and permanent seeding procedures, maintenance of a recently planted area, and fertilizer application rates: Temporary Seeding, Mulching and Matting, Clear Plastic Covering, Permanent Seeding and Planting, and Sodding as described in Volume II). • Selection of desired plant species can be made by adjusting the soil properties of the subject site. For example, a constructed wetland can be designed to resist the invasion of reed canary grass by layering specific strata of organic matters (e.g., compost forest product residuals) and creating a mildly acidic pH and carbon-rich soil medium. Consult a soil restoration specialist for site-specific conditions. • Aerate lawns regularly in areas of heavy use where the soil tends to become compacted. Aeration should be conducted while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than 3/4-inch deep. • Mowing is a stress-creating activity for turfgrass. When grass is mowed too short its productivity is decreased and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses, more disease prone and more reliant on outside means such as pesticides, fertilizers and irrigation to remain healthy. Set the mowing height at the highest acceptable level and mow at times and intervals designed to minimize stress on the turf. Generally mowing only 1/3 of the grass blade height will prevent stressing the turf. Irrigation: • The depth from which a plant normally extracts water depends on the rooting depth of the plant. Appropriately irrigated lawn grasses normally root in the top 6 to 12 inches of soil; lawns irrigated on a daily basis often root only in the top 1 inch of soil. Improper irrigation can encourage pest problems, leach nutrients, and make a lawn completely dependent on artificial watering. The amount of water applied depends on the normal rooting depth of the turfgrass species used, the available water holding capacity of the soil, and the efficiency of the irrigation system. Consult with the local water utility, Conservation District, or Cooperative Extension office to help determine optimum irrigation practices. February 2005 Vo/ume IV- Source Control BMPs 2-27 �'S Fertilizer Management: • Turfgrass is most responsive to nitrogen fertilization, followed by potassium and phosphorus. Fertilization needs vary by site depending on plant, soil and climatic conditions. Evaluation of soil nutrient levels through regular testing ensures the best possible efficiency and economy of fertilization. For details on soils testing, contact the local Conservation District or Cooperative Extension Service. • Fertilizers should be applied in amounts appropriate for the target vegetation and at the time of year that minimizes losses to surface and ground waters. Do not fertilize during a drought or when the soil is dry. Alternatively, do not apply fertilizers within three days prior to predicted rainfall. The longer the period between fertilizer application and either rainfall or irrigation, the less fertilizer runoff occurs. • Use slow release fertilizers such as methylene urea, IDBU, or resin coated fertilizers when appropriate, generally in the spring. Use of slow release fertilizers is especially important in areas with sandy or gravelly soils. � Time the fertilizer application to periods of maximum plant uptake. Generally fall and spring applications are recommended, although WSU turf specialists recommend four fertilizer applications per year. • Properly trained persons should apply all fertilizers. At commercial and industrial facilities fertilizers should not be applied to grass swales, filter strips, or buffer areas that drain to sensitive water bodies unless approved by the local jurisdiction. Integrated Pest Management An IPM program might consist of the following steps: Step 1: Correctly identify problem pests and understand their life cycle Step 2: Establish tolerance thresholds for pests. Step 3: Monitor to detect and prevent pest problems. Step 4: Modify the maintenance program to promote healthy plants and discourage pests. Step 5: Use cultural, physical, mechanical, or biological controls first if pests exceed the tolerance thresholds. Step 6: Evaluate and record the effectiveness of the control and modify maintenance practices to support lawn or landscape recovery and prevent recurrence. For an elaboration of these steps refer to Appendix IV-F. 2-28 Volume /V- Source Control BMPs February 2005 �G.► BMPS fOr Description of Pollutant Sources: Facilities include roadside catch Maintenance of basins on arterials and within residential areas, conveyance systems, Stormwater detention facilities such as ponds and vaults, oil and water separators, Drainage and biofilters, settling basins, infiltration systems, and all other types of Treatment stormwater treatment systems presented in Volume V. Roadside catch Systems basins can remove from 5 to 15 percent of the pollutants present in stormwater. When catch basins are about 60 percent full of sediment, they cease removing sediments. Oil and grease, hydrocarbons, debris, heavy metals, sediments and contaminated water are found in catch basins, oil and water separators, settling basins, etc. Pollutant Control Approach: Provide maintenance and cleaning of debris, sediments, and oil from stormwater collection, conveyance, and treatment systems to obtain proper operation. Applicable Operational BMPs: Maintain stormwater treatment facilities according to the O & M procedures presented in Section 4.6 of Volume V in addition to the following BMPs: • Inspect and clean treatment BMPs, conveyance systems, and catch basins as needed, and determine whether improvements in O &M are needed. • Promptly repair any deterioration threatening the structural integrity of the facilities. These include replacement of clean-out gates, catch basin lids, and rock in emergency spillways. • Ensure that storm sewer capacities are not exceeded and that heavy sediment discharges to the sewer system are prevented. • Regularly remove debris and sludge from BMPs used far peak-rate control, treatment, etc. and discharge to a sanitary sewer if approved by the sewer authority, or truck to a local or state government approved disposal site. • Clean catch basins when the depth of deposits reaches 60 percent of the sump depth as measured from the bottom of basin to the invert of the lowest pipe into or out of the basin. However, in no case should there be less than six inches clearance from the debris surface to the invert of the lowest pipe. Some catch basins (for example, WSDOT Type 1 L basins) may have as little as 12 inches sediment storage below the invert. These catch basins will need more frequent inspection and cleaning to prevent scouring. Where these catch basins are part of a stormwater collection and treatment system, the system owner/operator may choose to concentrate maintenance efforts on downstream control devices as part of a systems approach. 2-40 Volume /V- Source Control BMPs February 2005 5� • Clean woody debris in a catch basin as frequently as needed to ensure proper operation of the catchbasin. • Post warning signs; "Dump No Waste - Drains to Ground Water," "Streams," "Lakes," or emboss on or adjacent to all storm drain inlets where practical. • Disposal of sediments and liquids from the catch basins must comply with"Recommendations for Management of Street Wastes" described in Appendix IV-G of this volume. Additional Applicable BMPs: Select additional applicable BMPs from this chapter depending on the pollutant sources and activities conducted at the facility. Those BMPs include: • BMPs for Soil Erosion and Sediment Control at Industrial Sites • BMPs for Storage of Liquid, Food Waste, or Dangerous Waste Containers • BMPs for Spills of Oil and Hazardous Substances • BMPs for Illicit Connections to Storm Drains • BMPs for Urban Streets. February 2005 Volume /V- Source Control BMPs 2-41 �8 BMPs for Description of Pollutant Sources: Public and commercial parking lots Parking and such as retail store, fleet vehicle (including rent-a-car lots and car Storage of dealerships), equipment sale and rental parking lots, and parking lot Vehicles and driveways, can be sources of toxic hydrocarbons and other organic Equipment compounds, oils and greases, metals, and suspended solids caused by the parked vehicles. Pollutant Control Approach: If the parking lot is a high-use site as defined below, provide appropriate oil removal equipment for the contaminated stormwater runoff. Applicable Operational BMPs: • If washing of a parking lot is conducted, discharge the washwater to a sanitary sewer, if allowed by the local sewer authority, or other approved wastewater treatment system, or collect it for off-site disposal. • Do not hose down the area to a storm drain or to a receiving water. Sweep parking lots, storage areas, and driveways, regularly to collect dirt, waste, and debris. Applicable Treatment BMPs: An oil removal system such as an API or CP oil and water separator, catch basin filter, or equivalent BMP, approved by the local jurisdiction, is applicable for parking lots meeting the threshold vehicle traffic intensity level of a high-use site. Vehicle High-Use Sites Establishments subject to a vehicle high-use intensity have been determined to be significant sources of oil contamination of stormwater. Examples of potential high use areas include customer parking lots at fast food stores, grocery stores,taverns, restaurants, large shopping malls, discount warehouse stores, quick-lube shops, and banks. If the PGIS for a high-use site exceeds 5,000 square feet in a threshold discharge area, and oil control BMP from the Oil Control Menu is necessary. A high-use site at a commercial or industrial establishment has one of the following characteristics: (Gaus/King County, 1994) • Is subject to an expected average daily vehicle traffic (ADT) count equal to or greater than 100 vehicles per 1,000 square feet of gross building area: or • Is subject to storage of a fleet of 25 or more diesel vehicles that are over 10 tons gross weight(trucks, buses, trains, heavy equipment, etc.). 2-48 Volume IV- Source ControlBMPs February 2005 �9 BMPs for Roof/ Description of Pollutant Sources: Stormwater runoff from roofs and Building Drains sides of manufacturing and commercial buildings can be sources of at Manufacturing pollutants caused by leaching of roofing materials, building vents, and and Commercial other air emission sources. Vapors and entrained liquid and solid Buildings droplets/particles have been identified as potential pollutants in roof/building runoff. Metals, solvents, acidic/alkaline pH, BOD, and organics, are some of the pollutant constituents identified. Pollutant Control Approach: Evaluate the potential sources of stormwater pollutants and apply source control BMPs where feasible. Applicable Operational Source Control BMPs: • If leachates and/or emissions from buildings are suspected sources of stormwater pollutants, then sample and analyze the stormwater draining from the building. • If a roof/building stormwater pollutant source is identified, implement appropriate source control measures such as air pollution control equipment, selection of materials, operational changes, material recycle, process changes, etc. February 2005 Volume /V- Source ControlBMPs 2-51 �o BMPs for Spills Description of Pollutant Sources: Owners or operators of facilities of Oil and engaged in drilling, producing, gathering, storing, processing,transferring, Hazardous distributing, refining or consuming oil and/or oil products are required by Substances Federal Law to have a Spill Prevention and Control Plan if the storage capacity of the facility, which is not buried, is 1,320 gallons or more of oil, or any single container with a capacity in excess of 660 gallons and which, due to their location, could reasonably be expected to discharge oil in harmful quantities, as defined in 40 CFR Part 110, into or upon the navigable waters of the United States or adjoining shorelines {40 CFR 112.1 (b)}. Onshore and offshore facilities, which, due to their location, could not reasonably be expected to discharge oil into or upon the navigable waters of the United States or adjoining shorelines are exempt from these regulations {40 CFR 112.1(1)(i)}. Owners of businesses that produce Dangerous Wastes are also required by State Law to have a spill control plan. These businesses should refer to Appendix IV-D R.6. The federal definition of oil is oil of any kind or any form, including,but not limited to petroleum, fuel oil, sludge, oil refuse, and oil mixed with wastes other than dredged spoil. Pollutant Control Approach: Maintain, update, and implement an oil spill prevention/cleanup plan. Applicable Operational BMPs: The businesses and public agencies identified in Appendix IV-A that are required to prepare and implement an Emergency Spill Cleanup Plan shall implement the following: • Prepare an Emergency Spill Control Plan(SCP), which includes: - A description of the facility including the owner's name and address; - The nature of the activity at the facility; - The general types of chemicals used or stored at the facility; - A site plan showing the location of storage areas for chemicals, the locations of storm drains, the areas draining to them, and the location and description of any devices to stop spills from leaving the site such as positive control valves; - Cleanup procedures; - Notification procedures to be used in the event of a spill, such as notifying key personnel. Agencies such as Ecology, local fire department, Washington State Patrol, and the local Sewer Authority, shall be notified; - The name of the designated person with overall spill cleanup and notification responsibility; February 2005 Vo/ume /V- Source ControlBMPs 2-53 �( • Train key personnel in the implementation of the Emergency SCP. Prepare a summary of the plan and post it at appropriate points in the building, identifying the spill cleanup coordinators, location of cleanup kits, and phone numbers of regulatory agencies to be contacted in the event of a spill; • Update the SCP regularly; • Immediately notify Ecology and the local Sewer Authority if a spill may reach sanitary or storm sewers, ground water, or surface water, in accordance with federal and Ecology spill reporting requirements; • Immediately clean up spills. Do not use emulsifiers for cleanup unless an appropriate disposal method for the resulting oily wastewater is implemented. Absorbent material shall not be washed down a floor drain or storm sewer; and, • Locate emergency spill containment and cleanup kit(s) in high potential spill areas. The contents of the kit shall be appropriate for the type and quantities of chemical liquids stored at the facility. Recommended Additional Operational BMP: Spill kits should include appropriately lined drums, absorbent pads, and granular or powdered materials for neutralizing acids or alkaline liquids where applicable. In fueling areas: absorbent should be packaged in small bags for easy use and small drums should be available for storage of absorbent and/or used absorbent. Spill kits should be deployed in a manner that allows rapid access and use by employees. 2-54 Vo/ume /V- Source ControlBMPs February 2005 C�2 BMPs for Description of Pollutant Sources: Solid raw materials, by-products, or Storage or products such as gravel, sand, salts, topsoil, compost, logs, sawdust, wood Transfer chips, lumber and other building materials, concrete, and metal products (Outside) of sometimes are typically stored outside in large piles, stacks, etc. at Solid Raw commercial or industrial establishments. Contact of outside bulk materials Materials, with stormwater can cause leachate, and erosion of the stored materials. By-Products, or Contaminants include TSS, BOD, organics, and dissolved salts (sodium, Finished calcium, and magnesium chloride, etc). Products Pollutant Control Approach: Provide impervious containment with berms, dikes, etc. andlor cover to prevent run-on and discharge of leachate pollutant(s) and TSS. Applicable Operational BMP: Do not hose down the contained stockpile area to a storm drain or a conveyance to a storm drain or to a receiving water. Applicable Structural Source Control BMP Options: Choose one or more of the source control BMP options listed below for stockpiles greater than 5 cubic yards of erodible or water soluble materials such as soil, road deicing salts, compost, unwashed sand and gravel, sawdust, etc. Also included are outside storage areas for solid materials such as logs, bark, lumber, metal products, etc. • Store in a building or paved and bermed covered area as shown in Figure 2.13, or; �y�,�� . ;. � �/� ,«,:t;z�:.,n �S�,y,�� mr*? ��,�k'i ,<lo;" w �.�(�- 9-#`' �,1N�r� � °' �3, � J53 � f'Yy��` � ?{��` �� `�'^��'$� J��/�� Ft � � /�� :�d� ��k � s ��"�'�, ,� ,� �� i . r �,:.' ;�.. �,� �.- �.. 'S . . �y�� '� � :. � ' � �' Figure 2.13—Covered Storage Area for Bulk Solids(include berm if needed) • Place temporary plastic sheeting (polyethylene, polypropylene, hypalon, or equivalent) over the material as illustrated (see Figure 2.14), or; 2-60 Vo/ume /V- Source Contro/BMPs February 2005 � Figure 2.14—Material Covered with Plastic Sheeting • Pave the area and install a stormwater drainage system. Place curbs or berms along the perimeter of the area to prevent the run-on of unconta- minated stormwater and to collect and convey runoff to treatment. Slope the paved area in a manner that minimizes the contact between stormwater(e.g., pooling) and leachable materials in compost, logs, bark, wood chips, etc. • For large stockpiles that cannot be covered, implement containment practices at the perimeter of the site and at any catch basins as needed to prevent erosion and discharge of the stockpiled material offsite or to a storm drain. Ensure that contaminated stormwater is not discharged directly to catch basins without conveying through a treatment BMP. Applicable Treatment BMP: Convey contaminated stormwater from the stockpile area to a wet pond, wet vault, settling basin, media filter, or other appropriate treatment system depending on the contamination. Recommended Additional Operational BMPs: • Maintain drainage areas in and around storage of solid materials with a minimum slope of 1.5 percent to prevent pooling and minimize leachate formation. Areas should be sloped to drain stormwater to the perimeter where it can be collected, or to internal drainage "alleyways"where material is not stockpiled. • Sweep paved storage areas regularly for collection and disposal of loose solid materials. • If and when feasible, collect and recycle water-soluble materials (leachates) to the stockpile. • Stock cleanup materials, such as brooms, dustpans, and vacuum sweepers near the storage area. February 2005 Volume /V- Source Contro!BMPs 2-61 � � �.ri a . �.��y�.;,: ^�� \ //"� mawu n..�:�� .. � Y .,...c';;s., �es., uw.s.ar.ua.:.�e'�:.nmrtt�wv ::v: .�.rs•m'c' , .nv.:.i u�i, w.'ur+'.,....w¢<vw� .�wv�ra..<.:: ;. ..za.. . . .0 on s ��-w.dw..:::.:s LARSON AND ASSOCIATES LAND SURVEYORS & ENGINEERS, INC. 4401 SOUTH 66TH STREET TACOMA, WA 98409 !05 V�C��T`r IM�Pi�1 of 1 �� , �� http://www.geodata.org/output/cadastral maps55516442839.png 8/29/2013 Thurston Geodata Center- Parcel Search , Page 1 of 3 �v'�� -�.J�'nf�iNUTA'�''Zot.� ��n � ��§ � � Data for Parcel No. 21724410200 Zoom Map to Parcel Gaogle Earth (need to have Google Earth installed on you system) Google Maps Virtuai Earth Please make sure to READ our DATA DISCLA.IMF,R prior to utilizing our website for research View Assessor's Data for Parcel Owner(s): OUT OF BOUNDS PROPERTIES LLC Address: 6524 CROMWELL BEACH DR NW City: GIG HARBOR State: WA, 98335 Parcel No.: 21724410200 Site Address: 304 LONGMIRE RD NW Site City: YELM Site Zip: 98597 Sectic,n: S24171 E Abbreviated Legal: 24-17-1E 1A NE SE COM NW COR SOLBERG ADD N 52-4-0 W 200F POB S 37 Usecode: 91 Tax Code Area: 170 Taxable: Yes Annual Tax: View Property Taxes for Parcel Property Type: LND Total Acres: 1 � Land Value: View Assessor's Data for Parcel Building Value: View Assessor's Data for Parcel Total Value: View Assessor's Data for Parcel Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT �4� - http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410200 8/29/2013 Thurston Geodata Center- Parcel Search Page 2 of 3 Flood of 1999: Unknown Winter Flooding of 1996: Unknown High Groundwater Flood Hazards: Unknown Zoning: R-14, Commissioner District: Sandra Romero - District 2 Historic Site: Yes-Contact Cami Petersen at 360-754-3355 ext.6348 Permitting Jurisdiction: YELM Jurisdiction of Influence: Same as Permitting Jurisdiction Stormwater Rate: No No Shooting Zone: No Animal Control: Contact Animal Control (360-458-3244). Weed Containment Zone: No Steep Slopes Unknown Ground Water Sensitive Areas: No DNR Natural Heritage Data: Unknown Critical Buffers: No In 100 ft buffer of Shoreline Management No Areas: Waterbody&Wetland Buffers: No FEMA Panel No.: 0353 Wellhead Protection Area: No Area of Groundwater Concern: No Elevated Nitrates: No Soil Type: Spanaway gravelly sandy loam, 0 to 3% slopes; Spanaway gravelly sandy loam, 3 to 15% slop�s Hydric Soil: Unknown Watershed: NISQUALLY RIVER Water Service Area: YELM, CITY OF School Attendance District: YELM Elementary School: SOUTHWORTH Middle School: MILL POND AND YELM High School: YELM School Taxing District: View Assessor's Data for Parcel Fire Response District: SE THURSTON FIRE AND EMS Unconsalidated Fire Response District: YELM Fire Taxing District: View Assessor's Data for Parcel Medic Response District: Medic 2 Residential Outdoor Burning: Residential Outdoor Burning is banned within �Dg http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410200 8/29/2013 Thurston Geodata Center- Parcel Search Page 3 of 3 the city limits and urban growth areas. Planning Region: 2 Census Tract: 012411 Radio or Cell Tower: No Airport Zone: No Contamination: Unknown �9 - http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410200 8/29/2013 GEOTECHNICAL ENGINEERING STUDY For YELM APARTMENTS PARCEL #21724410200 304 LONGMIRE STREET, YELM, 98597 THURSTON COUNTY, WASHINGTON Prepared For MOUNTAIN TERRACE BUILDERS, LLC. 14730 STATE ROUTE 507 SE,YELM,WA 98597 Prepared By Pacific Geo Engineering Geotechnicel Engineering, Consulting 8F Inspection P.O. BOX 1419, ISSAQUAH, WASHINGTON 98027 PGE PROJECT NUMBER 13-420 September 23,2013 '7b �'��`fc �+�� `��►��,� Q��►��►►��►�r��.��,, c��z��►�► � septernber 23,2Q13 Mountain Terra+ce B�ild�rs,L.L� 1413(�S�te Rc�ut�5fl'7 SE 'Yel�n,WA 9$5�7 It�. G�otech�ic�1 Engxneering�k�dy Yelz� Apart�n�nts 3�4 La�s�mir�Stre�t Yelm,�Vs�shingttsn 9859'1 PGE F"rc�ject l�ta, 13-4�0 Ref.: Site Plan of'Yetm Apar�anents, prepared by I.,arson&Assac�ates. [�ar I�1�.7'ru�k: Pacific G�c� E��eering, LL� (PGE} h�s cor�pleted the g�t�ch�i��l engirteerin�; stvdy fc�r th� sut�ject SftE IpC��E',E� ��Ilk� R�lDl+f��t'F3S iti Y��1X1, T'k�urstan Caunty, l�Jashin�ton. This rep��t includes the res�lts of oc�r sub�urface explaration and engineerin�e�r�lc�ation, and �rrQUides rec�n�mendations far the gec�tech�ical aspects of the d�sign and deve�apment ofthe proj�cct. tNe trust the infe�rmation presenteci in this report is suf�ici�nit for y�ur currt;nt tteeds. We appreGiate the a�sp�rtanity t«� pravzde t�� eot�chnical services at this phass� of the prc�ject and laok fi�rward to coz�tinued. particip�tit�n durin� the desigt� and canstrt�ction phase af this project. Shc�u�d ya�z �ave ar�y question� or �c�racerns, which h�ve not been��dressed, c�r if we may be af additiona! assi�ta�ace, please da not hesit�te to�a1� us at 425-21$-9316 or�25-643-261 b. Resp�cctfully�€�brrtitteci, � , � a,. �: �7t�.+��:�,u�.-- ��i WL �� '�! � , � � �a�t�itartu 1'vlc�war,�4�SSCE,I'.E, ` � ;��c1fiC Ge�'�n��r�� '�y .r � ��:��»_� '� �� a �� `��,f�"t�:'�� ,��.,,.,,,�,.,�.��,,.�.�., '�� ,`��; �t P.t�. �a� 141.9. Is�aquah. �1VA. 98t}�7. �"�el� 425-543-26i�. ('F��} 4��-54�µ0436. TABLE OF CONTENTS Page No. 1.0 INTRODUC TION.............................................................................................................................................. 1 2.0 PROPOSED DEVELOPMENT....................................................................................................................... 1 3.0 SCOPE OF SERVICES..................................................................................................................................... 2 3.1 Field Investigation............................................................................................................................... 2 3.2 Laboratory Testing............................................................................................................................... 3 33 Engineering Evaluation....................................................................................................................... 3 4.0 SURFACE AND SUBSURFACE FEATURES.............................................................................................. 4 4.1 Site Location......................................................................................................................................... 4 4.2 Site Descriptions................................................................................................................................... 4 43 Regional Geology ................................................................................................................................ 4 4.4 Visual Soil Descriptions....................................................................................................................... 4 4.5 Groundwater Conditions....................................................................................................................... 5 5.0 CONCLUSIONS AND RECOMMENDATIONS.......................................................................................... 5 5.1 General................................................................................................................................................. 5 5.2 Site Preparation.................................................................................................................................... 6 5.2.1 Clearing and Grubbing......................................................................................................... 6 5.2.2 Subgrade Prepararion............................................................................................................ 6 5.2.3 Reuse of On-Site Soils.......................................................................................................... 7 5.2.4 Construction Season......................................................................................:...................... 8 5.2.5 Structural Fills...................................................................................................................... 8 5.2.6 Fill Placement&Compaction Requirements....................................................................... 9 5.2.7 Temporary Excavation Slopes ............................................................................................ 9 5.2.8 Permanent Cut and Fill Slopes ............................................................................................ 11 5.2.9 Construction Dewatering ..................................................................................................... 12 5.2.10 Construction Monitoring...................................................................................................... 12 53 Foundation Recommendations............................................................................................................ 12 5.4 Floor Slabs........................................................................................................................................... 14 5.5 Site Drainage........................................................................................................................................ 15 5.6 Utility Support and Bacicfill....:........................................................................................................... 16 5.7 PavementThickness............................................................................................................................ 17 5.8 Geologic Hazards................................................................................................................................ 18 5.8.1 Erosion Hazard..................................................................................................................... 18 5.8.2 Seismic Hazard..................................................................................................................... 18 5.8.3 Landslide Hazard.................................................................................................................. 19 5.9 Infiltration Potential Evaluation.......................................................................................................... 19 6.0 REPORT LIMITATIONS................................................................................................................................ 19 7.0 ADDITIONAL SERVICES.............................................................................................................................. 21 8.0 GEOTECHNICAL SPECIAL INSPECTIONS............................................................................................. 21 LIST OF FIGURES LIST OF APPENDICES Figure 1 Vicinity Map Appendix A Soil Test Pit Log Figure 2 Site&Exploration Plan ''�, 1 P��PaciFc Geo Engineering ..�.a..b,.�...M.�..n.,..� Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 1 1.0 INTRODUCTION This report presents the findings of our subsurface exploration and geotechnical engineering evaluation for a proposed development, to be located at 304 Longmire Street, Yelm, Washington. The general location of the site is shown on the Vicinity Map, Figure 1. The work was performed in general accordance with our proposal No. 13-06-390, dated July 09, 2013, which was authorized by the client on the same day. 2.0 PROPOSED DEVELOPMENT The development plan calls for constructing two apartment buildings, associated driveways and roadways, and shallow underground infiltration systems. Based on our experience with similar projects, we anticipate that the buildings will be single- or double-story wood-framed structures with loading carried primarily by a system of bearing walls.We expect bearing wall loads will be in the range of 2 to 3 kips per lineal foot, isolated column loads in the range of 30 to 40 kips, and slab-on-grade floor loads of 150 pounds per square foot (ps�. We further expect that the first floor levels of the buildings will be constructed at grade or framed over a crawl space area. Final grading plan is not prepared yet for the subject development. However, we assume that minor amount of cuts and fills are likely to take place across the proposed building pad areas of the subject tracts to achieve the final grades in this site. We understand some sort of storm water management system will be built in this site to manage the stormwater runoff and the rooftop water of the proposed development. The proposed development will include several asphalt-paved driveways. We anticipate vehicle traffic will primarily consist of passenger cars and occasional waste management trucks.The current topography of the site are shown on the Site and Soil Exploration Plan,Figure 2. The conclusions and recommendations contained in this report are based upon our understanding of the above design features of the development. We recommend that PGE should be allowed to review the final grades and the actual features after the final construction plans are prepared so that the conclusions and recommendations contained in this report may be re-evaluated and modified, if necessary. n3 PGEPacIFc Geo Enginee�ing ...�.�,.�..e�.�,.�,..A,..� Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 2 3.0 SCOPE OF SERVICES The purpose of this study was to evaluate the geotechnical aspects of the proposed development, and to identify and address the geotechnical issues that may impact the proposed site development. The scope of this geotechnical study included field explorations, laboratory testing, geologic literature review, and engineering evaluation of the field and laboratory data. This study also included interpretation of this information to generate pertinent geotechnical recommendations and conclusions that may be used for the design and construction of the development. The scope of our work did not include any wetland study, or any environmental analysis or evaluation to find the presence of any hazardous or toxic materials in the soil, surface water, groundwater, or air in or around this site. 3.1 Field Investigation We explored the subsurface conditions in the subject site on August 06, 2013. A total of nine (9) test pits planned by Larson and Associates were excavated during our explorations to depths of about 11 feet below the existing grades, and were backfilled with loosely compacted excavated soils. Several field percolation tests were performed in test pit TP-1,TP-2, and TP-7 at 4 feet below the current grades. The test pits were completed using a backhoe provided by the client. The specific number and the locations of the test pits were selected and plotted on the site plan, referenced above in item 2, prepared by Larson and Associates. This plan is reproduced in the Site and Soil Exploration Plan by PGE in Figure 2. An engineering geologist from our firm observed the excavations, continually logged the subsurface conditions in each test pit, collected representative bulk samples from different soil layers, and observed pertinent site features. Samples were designated according to the test pit number and depth, stored in watertight plastic containers, and later on transported to our laboratory for further visual examination. Results of the field investigation are presented on the test pit log,which is presented on Page A-1 of Appendix A. The final log is modified based on the interpretation of our field logs and visual examination of the samples in the laboratory. Due to the similar nature of soils encountered in the test pits throughout the site,only one test pit log is prepared representing the soils encountered in all test pits. 7� p�EPacifc Geo Engineering ...�.a,�,.,o�...N..�..�...�... Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 3 3.2 Laboratory Testing The bulk samples were visually classified in the field and laboratory, and later on supplemented by grain size analyses and moisture content tests to evaluate the general physical properties and engineering characteristics of the soils encountered. Two (2) Percent Passing #200 Sieve tests were performed on two (2) selected samples in accordance with the ASTM D-1140 procedure, the results of which are presented in the test pit log in Appendix A. 3.3 Engineering Evaluation The results from the field and laboratory tests were evaluated and engineering analyses were performed to provide pertinent information and recommendations on the following geotechnical aspects of the proposed site development: • Soil and groundwater conditions of the site. • Earthwork including site preparation, clearing and grubbing, excavation, placement and compaction of structural fills, and subgrade preparation. • Structural fills and use of the on-site soils as structural fill. • Dry weather construction. • Temporary and permanent excavation slopes. • Temporary construction dewatering. � • Site drainage including permanent subsurface drainage systems and temporary groundwater control measures, if necessary. • Foundation types and allowable bearing capacity for supporting the proposed residences. • Settlement due to the recommended bearing capacity and observed soil conditions. • Frictional and passive values for the resistance of lateral forces. • Subgrade preparation for slab-on-grade. • Seismic design considerations, including the site coefficient per IBC 2003. • Pavement thickness recommendations. • Geologic hazards: erosion, seismic, and landslide. • Infiltration rates of native soils in the proposed storm tract area. • Geotechnical special inspection requirements. � PGEPacitic Geo Engineering ...�,�,a....��,..n...�.. Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 4 4.0 SURFACE AND SUBSURFACE FEATURES 4.1 Site Locations The subject site is located at 304 Longmire Street in Yelm, Thurston County, Washington,which is shown on the Vicinity Map,Figure 1. 4.2 Site Descriptions The site has an access near its southwestern corner from the intersection of Berry Valley Dr. and Longmire St. SE. In general, the site is almost a level ground with minor downward slope from its northern edge to the southern edge, with the elevations range from 342 to 348. The topography is shown on the Site&Exploration Plan,Figure 2. 4.3 Regional Geology The site is in the Puget Sound Lowland, a north-south trending structural and topographic depression lying between Olympic Mountains on the west and Cascade Mountains on the east. The lowland depression experienced successive glaciation and nonglaciation activities over the time of Pleistocene period. During the most recent Fraser glaciation, which advanced from and retreated to British Columbia between 13,000 and 20,000 years ago, the lowland depression was buried under about 3,000 feet of continental glacial ice. During the successive glacial and nonglacial intervals, the lowland depression, which is underlain by Tertiary volcanic and sedimentary bedrock, was filled up above the bedrocks to the present-day land surface with Quaternary sediments, which consisted of Pleistocene glacial and nonglacial sediments. The glacial deposits include concrete-like lodgement till, lacustrine silt, fine sand and clay, advance and recessional outwash composed of sand or sand and gravel, and some glaciomarine materials. The nonglacial deposits include largely fluvial sand and gravel, overback silt and clay deposits, and peat attesting to the sluggish stream environments that were apparently widespread during nonglacial times. 4.4 Visual Soil Descriptions In general, the site is underlain by approximately 24 inches thick brown silty sandy soils containing abundant gravels and cobbles, and roots and organics. This soils are underlain by a soil deposit consisted of primarily gravels, cobbles, and boulders with some sands and trace silts upto the bottom of the exploration depths. In general,the soils are in loose consistencies in the upper 4 feet depth, and in medium dense consistencies below that depth. The soils have good permeability characteristics. '?Co /'f�cPaciFc Geo Engineering — �...'.�.,�r�n�a�.r+�,4oe,..rN..z...w.,, Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 5 4.5 Groundwater Conditions No groundwater or seepage, or any sign of mottling was noticed in the test pits within their exploration depths. It is to be noted that seasonal fluctuations in the groundwater elevations and the presence of perched water in the upper permeable loams may be expected in the amount of rainfall, surface runoff, and other factors not apparent at the time of our exploration. Typically, the groundwater levels rise higher and the seepage flow rates increase during the wet winter months in the Puget Sound area. The possibility of groundwater level fluctuations and the presence of perched water.and seepage through excavations must be considered when designing and developing the proposed development in this site. The preceding discussion on the subsurface conditions of the site is intended as a general review to highlight the major subsurface stratification features and material characteristics. For more complete and specific information at individual test pit locations, please review the Test Pit Log (Page A-1) included in Appendix A. This log include soil descriptions, stratification, and location of the samples and laboratory test data. It should be noted that the stratification lines shown on the log represent the approximate boundaries between various soil strata; actual transitions may be more gradual or more severe. The subsurface conditions depicted in the log are for the test pit locations indicated only, and it should not necessarily be expected that these conditions are representative at other locations of the site. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 General Based on this study, there are no geotechnical considerations that would preclude the proposed development as planned,therefore,the subject site is considered suitable for the proposed development. The proposed structures, e.g., buildings, slab-on-grades, driveways, pavements, and any other structures may be supported on the native soils, provided the final subgrades for such structures are to be prepared as per the recommendations provided in this section and in its following sections. We recommend that the building footings, floor slabs if slab-on-grade type is chosen, the driveways and the pavements, and any other structures must be placed on the firm, unyielding soils, either consisted of native soils, existing fills, or newly placed structural fills. The final grade preparation and the final grades to support any structures must be monitored and approved, respectively, by the geotechnical special inspector during the construction phases of the project. Based on the findings of our subsurface explorations the native soils encountered in this site within the shallow depths of approximately 4 feet below the existing grades are found in general,in loose �� P�!�Pacifc Geo Engineering V .oe.a,�.�,�.....«�.a.,r,..,..n...�,.�, Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 6 consistencies. If these soils have to support new structures, e.g., foundations, floor slabs, retaining walls, driveways, pavements, new structural fills, and any other structures then these soils must be adequately proofrolled with a big vibratory roller to increase these sand deposits' compactions and their bearing capacity values. In addition to the regular proofrolling effort we believe that extra compaction effort will be needed to compact the upper loose soil deposits and to transmit the compaction effort to greater depths. It should be noted that the proofrolling and the resulting compactions of the soil deposits should be achieved to its firm and unyielding conditions, and to a minimum of 95% compaction of the native sand's Modified Proctor dry density value to develop a stable and firm final subgrades. The soil deposits encountered in the test pits are found of good permeability characteristics, therefore, are considered to be conducive for installing infiltration system. The remainder of this section (5.0) presents specific engineering recommendations on the pertinent geotechnical aspects that are anticipated for the design and construction of the proposed development. These recommendations should be incorporated into the final design and drawings, and construction specifications. 5.2 Site Preparation Preparation of the site should involve clearing, stripping, subgrade proofrolling, cutting, filling, excavations, dewatering, and drainage installations. The following paragraphs provide specific recommendations on these issues. 5.2.1 Clearing and Grubbing Initial site preparation for construction of new buildings, driveways, pavements, and any other structures should include stripping of vegetation and topsoil from the site. Based on the topsoil thickness encountered at our test pit locations, we anticipate topsoil stripping depths of about 12 to 18 inches, however, thicker layers of topsoil may be present in unexplored portions of the site. It should be realized that if the stripping operation takes place during wet winter months, it is typical a greater stripping depth might be necessary; therefore, stripping is best performed during dry weather period. Stripped vegetation debris should be removed from the site. Stripped organic topsoils will not be suitable for use as structural fill but may be used for future landscaping purposes. 5.2.2 Subgrade Preparation After the site clearing and site stripping, cut and fill operations can be initiated to establish desired driveways and building grades. Any exposed subgrades that are intended to provide direct �� Pacifc 6eo Engineering �.ee.a.d,.ews.nrr,a.,..rew.z...vua Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 7 support for new construction and/or require new fills should be adequately proofrolled to evaluate their condition. Proofrolling should be done with a loaded dump truck or front-end loader under the supervision of a geotechnical engineer, and/or must be probed with a T-probe by the geotechnical engineer to identify the presence of any isolated soft and yielding areas and to verify that stable subgrades are achieved to support the buildings, driveways, and the new fills. As mentioned earlier in Section 5.1, in addition to the regular proofrolling an extra compaction effort will be required during the proofrolling of the native sand deposit to enhance their bearing capacity values. It should be noted that the proofrolling and the resulting compactions of the sand deposits should be achieved to its firm and unyielding conditions, and to a minimum of 95% compaction of the native sand's Modified Proctor dry density value to develop a stable and firm final subgrades. The loosely backfilled soils in the areas of exploratory test pits should be overexcavated completely to the firm native soils and backfilled with adequately compacted new structural fills to the final grades. Tree stumps and large root balls should be removed completely and backfilled with new structural fills to the desired subgrade levels. 5.2.3 Reuse of On-Site Soils The ability to use on-site soils obtained from the site excavations as structural fills depends on the gradation, moisture content of the soils, and the prevailing weather conditions exist during the grading activities. As the fines content(that portion passing the U.S.No. 200 sieve)of a soil increases, it becomes increasingly sensitive to small changes in moisture content, and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines by weight cannot be consistently compacted to the recommend degree when the moisture content is more than about 2 percent above or below the optimum. The native sand encountered in the test pit locations has percentages passing #200 sieve ranges from 0.7% to 1.3%. Based on these very low fines content the native soils are considered suitable for reusing them as new structural fills during the any weather period, dry or wet. However, it should be noted that the native soils are primarily consisted of gravels, cobbles, and boulders, which may pose some problem during their compaction to achieve 95%of the soils'dry density value determined from the laboratory testing method. Care should be taken during the laying of the native soils to avoid clustering of excessive gravels, cobbles, and builders in any one location, which otherwise would pose problem during the compaction. The top 12 inches of compacted structural fill layer should have a maximum 2 to 3-inch particle diameter and all underlying fill a maximum 4 to 6-inch diameter unless specifically approved by the geotechnical engineer. An experienced geotechnical inspector should be monitoring the fill placement and the compaction to avoid the above issues during the fill operations. '�°� PGEP�ciFc Geo Engineering o.�,��.�..� Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 8 In the event that whether the structural fill materials are to be imported to the site, or if on-site soils are to be reused as structural fill, we recommend that the potential structural fill materials be verified and approved by the project geotechnical engineer prior to their use. However, it should be noted that the native soils are primarily consisted of gravels, cobbles, and boulders, which may pose problem during the compactions of this soils to 95% of the soils' dry density value to be determined based on the laboratory testing method. 5.2.4 Construction Season Due to the low fines content in the native soils, the proposed site development activities can takes place in any weather period, dry or wet. However, construction in wet weather season may contribute some minor erosion related problems in this site. This may particularly happen, when uncontrolled surface runoff is allowed to flow over unprotected excavation areas during the wet winter months. 5.2.5 Structural Fills Structural fill is defined as non-organic soil, free of deleterious materials, and well-graded and free-draining granular material, with a maximum of 5 percent passing the No. 200 sieve by weight, and not exceeding 6 inches for any individual particle. A typical gradation for structural fill is presented in the following table. Structural Fill U.S. Standard Sieve Size Percent Passing by Dry Weight 3 inch 100 3/ inch 50—100 No. 4 25—65 No. 10 10—50 No. 40 0—20 No. 200 5 Maximum* *Based on the 3/ inch fraction. Other materials may be suitable for use as structural fill provided they are approved by the project geotechnical engineer. Such materials typically used include clean, well-graded sand and gravel (pit-run); clean sand; various mixtures of gravel; crushed rock; controlled-density-fill (CDF); and lean- mix concrete (LMC). Recycled asphalt, concrete, and glass, which are derived from pulverizing the � ��CPacific Geo Engineering L..m,��.,.-.�.�a.r.»a..z...�.. Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 9 parent materials are also potentially useful as structural fill in certain applications. These materials must be thoroughly crushed to a size deemed appropriate by the geotechnical engineer (usually less than 2 inches). The top 12 inches of compacted structural fill should have a maximum 2 to 3-inch particle diameter and all underlying fill a maximum 4 to 6-inch diameter unless specifically approved by the geotechnical engineer. 5.2.6 Fill Placement and Compaction Requirements Generally, quarry spalls, controlled density fills (CDF), lean mix concrete (LMC) do not require special placement and compaction procedures. In contrast, clean sand, crushed rock, soil mixtures and recycled materials should be placed under special placement and compaction procedures and specifications described here. Such structural fills under structural elements should be placed in uniform loose lifts not exceeding 12 inches in thickness for heavy compactors and 4 inches for hand held compaction equipment. Each lift should be compacted to a minimum of 95 percent of the soil's laboratory maximum dry density as determined by ASTM Test Designation D-1557 (Modified Proctor) method, or to the applicable minimum City or County standard, whichever is the more conservative. The fill should be moisture conditioned such that its final moisture content at the time of compaction should be at or near (typically within about 2 percent) of its optimum moisture content, as determined by the ASTM method. If the fill materials are on the wet side of optimum, they can be dried by periodic windrowing and aeration or by intermixing lime or cement powder to absorb excess moisture. In-place density tests should be performed to verify compaction and moisture content of the fills and base materials. Each lift of fill or base material should be tested and approved by the soils engineer prior to placement of subsequent lifts. As a guideline, it is recommended that field density tests be performed at a frequency of not less than 1 test per 2,000 square feet of surface area per lift in the building and pavement areas. If field density tests indicate that the last lift of compacted fills has not been achieved the required percent of compaction or the surface is pumping and weaving under loading, then the fill should be scarified, moisture-conditioned to near optimum moisture content,re-compacted, and re-tested prior to placing additional lifts. 5.2.7 Temporary Excavation Slopes The owner and the contractor should be aware that in no case should the excavation slopes be greater than the limits specified in local, state, and federal safety regulations, particularly, the Occupational Safety and Health Administration (OSHA) regulations in the "Construction Standards for Excavations, 29 CFR,part 1926, Subpart P, dated October 31, 1989"of the Federal Register,Volume 54, 8i PGEPaciFc Geo Engineerfng .�.a,�,.�..+�.�.�,,..s...�.A Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 10 the United States Department of Labor. As mentioned above, we also recommend that the owner and the contractor should follow the local and state regulations such as WSDOT section 2-09.3(3)B,Washington Industrial Safety and Health Act (WISHA), Chapter 49.17RCW, and Washington Administrative Code (WAC) Chapter 296-115, Part N. These documents are to better insure the safety of construction worker entering trenches or excavation. It is mandated by these regulations that excavations, whether they are for utility trenches or footings, be constructed in accordance with the guidelines provided in the above documents. We understand that these regulations are being strictly enforced and, if they are not closely followed,both the owner and the contractor could be liable for substantial penalties. Stability of temporary excavations is a function of many factors including the presence of and abundance of groundwater and seepage, the type and density of the various soil strata, the depth of excavation, surcharge loadings adjacent to the excavation, and the length of time and weather conditions while the excavation remains open. It is exceedingly difficult under these unknown and variable circumstances to pre-establish a safe and maintenance-free temporary excavation slope angle at this time of the study. We therefore, strongly recommend that all temporary, as well as permanent, cuts and excavations in excess of 4 feet be examined by a geotechnical engineer during the actual construction to verify that the recommended slope inclinations in this section are appropriate for the actual soil and groundwater seepage conditions exposed in the cuts. If the conditions observed during the actual construction are different than anticipated during this study then,the proper inclination of the excavation and cut slopes or requirements of temporary shoring should be determined depending on the condition of the excavations and the slopes. As a general rule, all temporary soil cuts greater than 4 feet in height associated with site regarding or excavations should be adequately sloped back or properly shored to prevent sloughing and collapse. As for the estimation purposes, in our opinion, for temporary excavations equal to the exploration depths, the side slopes should be laid back at a minimum slope inclination of 3:1 (Horizontal:Vertical) for the native loose to medium dense soil deposits. The recommended inclinations assumes that the ground surface behind the cut slopes is level, that surface loads from equipment and materials are kept a sufficient distance away from the top of the slope. If these assumptions are not valid, we should be contacted for additional recommendations. Flatter slopes may be required if soils are loose or caving and/or water, are encountered along the slope faces. If such conditions occur and the excavation cannot stand by itself, or the excavation slope cannot be flattened because of the space limitations between the excavation line and the boundary of the property, temporary shoring may be considered. The shoring will assist in preventing slopes from failure and provide protection to field personnel during excavation. Because of the diversity available of shoring stems and construction techniques, the design of temporary shoring is most appropriately left up �Z- P/'��PaciFc Geo Engineering V ..�.d�.�.r.,.�,m,.�,..�....d.M Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 11 to the contractor engaged to complete the installation. We can assist in designing the shoring system by providing with detailed shoring design parameters including earth-retaining parameters, if required. Where sloped embankments are used, the top of the slopes should be barricaded to prevent vehicles and storage loads within 10 feet of the top of the slopes. Greater setbacks may be necessary when considering heavy vehicles, such as concrete trucks and cranes. If the temporary construction embankments are to be maintained during the rainy season, berms are suggested along the top of the slopes to prevent runoff water from entering the excavation and eroding the slope faces. All temporary slopes should be protected from surface water runoff. The above information is provided solely for the benefit of the owner and other design consultants, and under no circumstances should not be construed to imply that PGE assumes responsibility for construction site safety or the contractor's activities; such responsibility is not being implied and should not be inferred. Therefore, the contractor is solely responsible for designing and constructing stable, temporary excavations and should shore, slope, or bench the sides of the excavations as required to maintain stability of both the excavation sides and bottom. The contractor's "responsible person", as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor's safety procedures. We expect that the excavation can be completed using conventional equipments such as bulldozers or backhoes. 5.2.8 Permanent Cut and Fill Slopes For permanent cut slopes the side slopes should be laid back at a minimum slope inclination of 3:1. Where the above slopes are not feasible, protective facings and/or retaining structures should be considered. Temporary erosion protection described later on in Section 5.8.1 of this report should be used until permanent protection is established. Cut slopes should be re-vegetated as soon as practical to reduce the surface erosion and sloughing. We recommend that any permanent fill slope be constructed no steeper than 2H:1V. To achieve uniform compaction, we recommend that fill slopes be overbuilt slightly and subsequently cut back to expose well compacted fill. We recommend that a permanent berm, swale, or curb be constructed along the top edge of all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as soon as feasible, to further protect the slopes from runoff water erosion. Alternatively,permanent slopes could be armored with quarry spalls or a geosynthetic mat. �3 j'y/'!CPaciFc Geo Enginee�ing rf vG...�,�....,.,a.�...N..n...e.,a, Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 12 5.2.9 Construction Dewatering If the regional groundwater levels rise above the planned excavation base during the winter and spring months, the contractor should be prepared to dewater the excavations especially the underground utility trenches. If localized (perched) groundwater or minor seepage is encountered, we anticipate that internal collection ditches directing water inflow to sumpholes and then removal of water by conventional filtered sump pumps will be adequate to temporarily dewater the excavations and to maintain a relatively dry working area for construction purposes. The dewatering must remain in operation to maintain a dry working condition throughout the construction period in the trenches. If severe water conditions encountered, more specialized dewatering techniques, such as vacuum wells, well points, etc., may be needed. However, these more extensive dewatering techniques can lead to settlement of the ground surface in the surrounding vicinity when the groundwater is drawn down. If such dewatering techniques are contemplated a geotechnical engineer should be consulted for specific design and construction recommendations for the excavation areas. 5.2.10 Construction Monitoring Problems associated with earthwork and construction can be avoided or corrected during the progress of the construction if proper inspection and testing services are provided. It is recommended that site preparation activities including but not limited to stripping, clearing, cut and filling, final subgrade preparation for foundation, floor slab, and pavement be monitored by a special geotechnical inspector. PGE can assist the owner before construction begins to develop an appropriate monitoring and testing plan to aid in accomplishing a fast and cost-effective construction process. A list of items to be inspected as a geotechnical special inspection services are recommend later on in Section 8.0 of this report. 5.3 Foundations Recommendations Spread Footin� Based on the subsurface conditions encountered in our test pits, it is our opinion that the proposed buildings can be supported on conventional shallow strip and spread footings. The footings � PGEPacifPc Geo Engineering ..�,�...,.�..n...�.. Geotechnical Engineering Study • Yelm Apartments Project No. 13-420 September 23,2013 Page 13 should be supported on the firm native soils or on new structural fills placed above the properly proofrolled native subgrades as described earlier in Section 5.1 and 5.2 of this report. The new structural fills may be consisted of well-graded sands and gravels, such as `Ballast' per WSDOT Standard Specifications 9-039(1), or uniformly graded crushed rock, such as `Crushed Surfacing Base Course' per WSDOT Standard Specifications 9-03.9(3), structural fills described earlier in Structural Fill Table of Section 5.2.5. If the construction takes place during dry summer period and if the optimum moisture content of these soils is maintained during the compaction the on-site silty soil could also be used as building pad materials. All bearing pad soils should be compacted to at least 95 percent of the Modified Proctor maximum dry density value (ASTM:D-1557). Controlled density fills (CDF) and lean mix concrete (LMC) should be used for higher bearing pressure (more than 2500 ps fl footing in order to maintain adequate bearing capacities. The footing bearing pads if constructed with new structural fills need to be extended beyond the actual outer edges of the footings. This is because footing stresses are transferred outward as well as downward into the bearing pad soils. All footing bearing pads should extend horizontally outward from the edge of the footing a distance equal to the bearing pad thickness (1H:1V). For bearing pads composed of controlled density fills (CDF)or lean mix concrete(LMC)the horizontal distance should be at least half of the fill depth. For the design of shallow footing foundation supported on the above-described native soils or properly compacted structural fill we recommend using a maximum net allowable bearing capacity of 1500 pounds per square foot (ps�. For short-term loads, such as wind and seismic, a 1/3 increase in this allowable capacity can be used. We recommend that continuous footings have a minimum width of 12, 15, and 18 inches for 1-, 2-, and 3-strory residential structures as presented in the Table 1805.4.2 of 2003 International Building Code (IBC). We recommend a minimum width of 24 inches for the individual column footings. Based on our settlement potential evaluation in this site, we anticipate that properly designed and constructed foundations supported on the recommended materials should experience total and differential settlements of less than 1 inch and 1/2 inch, respectively. Most of these settlements are expected to occur immediately following the building loads are applied. The predicted settlement values may be expected larger if soft, loose, organic soil is encountered, or if the foundation subgrade is disturbed and becomes soft during construction. The settlement evaluation was done without the aid of any laboratory consolidation test data,and on the basis of our experience with similar types of structures and subsoil conditions. Lateral foundation loads can be resisted by friction between the foundation base and the supporting soil, and by passive earth pressure acting on the face of the embedded portion of the g� j'��Pacific Geo Engineering r" ...e.�,.�..w�a.,,.,.�,,..m,..a... Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 14 foundation. We recommend using a coefficient of friction of 0.4 to calculate friction between the concrete, and the native soils or the structural fills. For passive earth pressure, the available resistance may be determined using an equivalent fluid pressure of 300 pcf, which includes a factor of safety of 1.5. This value assumes the foundations are cast "neat" against the undisturbed native soils or structural fills placed and compacted as recommended in Section 5.2 of this report. We recommend to disregard the upper 12 inches of soil while computing the passive resistance value because this depth can be affected by weather or disturbed by future grading activity. To achieve the adequate passive resistance from the embedded soils as well as for frost and erosion protection, we recommend that all exterior footings must be embedded at least 18 inches below the final adjacent outside grades consisted of either the undisturbed native soils or structural fills placed and compacted as recommended in Section 5.1 and 5.2 of this report. The interior footings may be embedded only 12 inches below the surrounding slab surface level. Variations in the quality and strength of these potential bearing soils can occur with depth and distance between the test pits. Therefore, careful evaluation of the appropriate bearing materials is recommended at the time of construction to verify their suitability to support the above recommended bearing pressure. We recommend that a PGE representative examine the bearing materials prior to placing forms or rebar. 5.4 Floor Slabs If slab-on-grade option is chosen for the buildings then the slab-on-grade floors should bear on the properly prepared subgrades as discussed earlier in Section 5.1 and 5.2. All soil-supported slab-on- grade floors should bear on firm,unyielding native soils or on suitable properly compacted structural fill. After subgrade preparation is completed, the slab should be provided with a capillary break to retard the upward wicking of ground moisture beneath the floor slab. The capillary break would consist of a minimum of 6-inch thick clean, free-draining sand or pea gravel. The structural fill requirements specified in Structural Fill Table of Section 5.2.5 could be used as capillary break materials except that there should be no more than 2 percent of fines passing the no. 200 sieve. Alternatively, `Gravel Backfill for Drains' per WSDOT Standard Specifications 9-03.12(4) can be used as capillary break materials. Where moisture by vapor transmission is undesirable, we recommend the use of a vapor barrier such as a layer of durable plastic sheeting (such as Crossstuff, Moistop, or Visqueen) between the capillary break and the floor slab to prevent the upward migration of ground moisture vapors through the slab. During the casting of the slab, care should be taken to avoid puncturing the vapor barrier. At owner's or architecture's discretion, the membrane may be covered with 2 inches of clean, moist sand as a `curing course' to guard against damage during construction and to facilitate uniform curing of the overlying concrete slab. The addition of 2 inches of sand over the vapor barrier is a non-structural recommendation. Based on the subgrade preparation as described in Section 5.1 and 5.2 of this report, a modulus of � P/_'��PaciFc Geo Engineering �.7 ...e.a,.d,.+o+....�,..�.,..�...s...�..,, Geotechnical Engineering Study , Yelm Aparhnents Project No. 13-420 September 23,2013 Page 15 subgrade reaction value of about 150 pounds per cubic inch(pci)can be used to estimate slab deflections, which could arise due to elastic compression of the subgrades. 5.5 Site Drainage Surface Draina�e The final site grades must be such that surface runoff will flow by gravity away from the structures, and should be directed to suitable collection points. We recommend providing a minimum drainage gradient of about 3% for a minimum distance of about 10 feet from the building perimeter. A combination of using positive site surface drainage and capping of the building surroundings by concrete, asphalt, or low permeability silty soils will help minimize or preclude surface water infiltration around the perimeter of the buildings and beneath the floor slabs. Driveways should be graded to direct runoff to catch basins and or other collection facilities. Collected water should be directed to the on-site drainage facilities by means of properly sized smooth walled PVC pipe. Interceptor ditches or trenches or low earthen berms should be installed along the upgrade perimeters of the site to prevent surface water runoff from precipitation or other sources entering the site. Surface water collection facilities should be designed by a professional civil engineer. Footin�Excavation Drain Water must not be allowed to pond in the foundation excavations or on prepared subgrades either during or after construction. If due to the seasonal fluctuations, groundwater seepage is encountered within footing depths, we recommend that the bottom of excavation should be sloped toward one corner to facilitate removal of any collected rainwater, groundwater, or surface runoff, and then direct the water to ditches, and to collect it in prepared sump pits from which the water can be pumped and discharged into an approved storm drainage system. Footin�D� Footing drains should be used where (1) crawl spaces or basements will be below a structure, (2) a slab below the outside grade, and (3) the outside grade does not slope downward from a building. The drains must be laid with a gradient sufficient to promote positive flow to a controlled point of approved discharge. The foundation drains should be tightlined separately from the roof drains to this discharge point. Footing drains should consist of at least 4-inch diameter perforated PVC pipe. The pipe should be placed in a free-draining sand and gravel backfill. Either the pipe or the pipe and free-draining backfill should be wrapped in a non-woven geotextile filter fabric to limit the ingress of fines. Cleanouts should be provided. In the flatter areas of the site the drains should be located on the outside of the spread �d''7 P/"!��Pacific Geo Engineering V ..�„d,�..�.�,�,,..n,..� Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 16 footings. In sloped areas of the site, the footing drains should be installed at the inner base of the lower perimeter footings and at the outer base of the upper and the side perimeter footings. Downspout or Roof Drain These should be installed once the building roof is in place. They should discharge in tightlines to a positive, permanent drain system. Under no circumstances connect these tightlines to the perimeter footing drains. 5.6 Utility Support and Backfill Based on the soils encountered at the site within the exploration depths, the majority of the soils appear to be adequate for supporting utility lines; however, softer soils may be encountered at isolated locations, where, it should be removed to a depth that will provide adequate support for the utility. A major concern with utility lines is generally related to the settlement of trench backfill along utility alignments and pavements. Therefore, it is important that each section of utility be adequately supported on proper bedding material and properly backfilled. It is recommend that utility trenching, installation, and backfilling conform to all applicable Federal, State, and local regulations such as WISHA and OSHA for open excavations. Utility bedding should be placed in accordance with manufacturer's recommendations and local ordinances. Bedding material for rigid and flexible pipe should conform to Sections 9-03.15 and 9-03.16, respectively, of the 1994 WSDOT/APWA (American Public Works Association) Standard Specifications for Road, Bridge, and Municipal Construction. For site utilities located within the Pierce County right-of-ways, bedding and backfill should be completed in accordance with the Pierce County specifications. As a minimum, 5/8 inch pea gravel or clean sand may be used for bedding and backfill materials. The bedding materials should be hand tamped to ensure support is provided around the pipe haunches. Trench backfill should be carefully placed and hand tamped to about 12 inches above the crown of the pipe before any heavy compaction equipment is brought into use. The remainder of the trench backfill should be placed in lifts having a loose thickness of less than 12 inches and compacted to 90 percent of the maximum dry density per ASTM Test Designation D-1557 (Modified Proctor) except for the uppermost foot of backfill which should be compacted to 95 percent of the maximum dry density per ASTM Test Designation D-1557 (Modified Proctor). The utility trenches should not be left open for extended periods to prevent water entry and softening of the subgrade. Should soft soils be encountered at the bottom of the trench, it should be overexcavated and replaced with select fills. As an alternative to undercutting, a Geotextile fabric or crushed rock may be used to stabilize the trench subgrade. Where water is encountered in the trench �a P�!�Pacifc Geo Engineering V ...�,e,w�..e�.a.,�.�,...s...d,.,. Geotechnical Engineering Study Yelm Apartments Project No. 13-420 September 23,2013 Page 17 excavations, it should be removed prior to fill placement. Alternatively, quarry spalls or pea gravel could be used below the water level if allowed in the project specifications. 5.7 Pavement Thickness A properly prepared subgrade is very important for the life and performance of the driveway pavements. Therefore, we recommend that all driveway and pavement areas be prepared as described in Section 5.1 and 5.2 of this report. Subgrades should either be comprised of adequately proofrolled competent undisturbed native soils, or be comprised of a minimum of one foot of granular structural fill that is compacted adequately. The structural fill should be compacted to 95 percent of the maximum dry density as determined by Modified Proctor (ASTM Test Designation D-1557). It is possible that some localized areas of yielding and weak subgrade may still exist after this process. If such conditions occur, crushed rock or other qualified materials as addressed in Section 5.2.5 may be used to stabilize these localized areas. We assumed that the traffic would mostly consist of passenger cars and occasional waste management trucks, which is typical for a residential community. Two types of pavement sections may be considered for such traffic,the minimum thicknesses of which are as follows: • 2 inches of Asphalt Concrete (AC) over 2 inches of Crushed Surface Top Course (CSTC) over a 6 inches of Granular Subbase, or • 2 inches of Asphalt Concrete(AC)over 3 inches of Asphalt Treated Base(ATB)material. The 1998 Standard Specifications for Washington State Department of Transportation(WSDOT) and American Public Works Association (APWA) should be applicable to our recommendations that aggregate for AC should meet the Class-B grading requirements as specified in 9-03.8(6). For the Crushed Surfacing Top Course(CSTC), we recommend using imported, clean, crushed rock per WSDOT Standard Specifications 9-03.9(3). For the sub base course, we recommend using imported, clean, well- graded sand and gravel, such as Ballast or Gravel Borrow per WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively. For the asphalt treated base course (ATB) the aggregate should be consistent with WSDOT Standard Specifications 9-03.6(2). Long-term performance of the pavement will depend on its surface drainage. A poorly-drained pavement section will deteriorate faster due to the infiltration of surface water into the subgrade soils, thereby reducing their supporting capability. Therefore, we recommend using a minimum surfacing drainage gradient of about 1% to minimize this problem and to enhance the pavement performance. Also, regular maintenance of the pavement must be considered. � /'�f!�Pacifc Geo Engineering /"y ...�,�,�.....�.�..s...�, Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 18 5.8 Geologic Hazards 5.8.1 Erosion Hazard Uncontrolled surface water with runoff over unprotected site surfaces during construction activities is considered the single most important factor that impacts the erosion potential of a site. The erosion process may be accelerated significantly when factors such as soils with high fines, sloped surface, and wet weather combines together. Taking into consideration of the fines content(0.7 to 1.3%)in the near surface sands, the project site may have some minor or no impact due to erosion during the wet winter months. The erosion hazard can be mitigated if the mass grading activities and the earthwork can be completed within the dry summer period. Also, measurements such as the control of surface water must be maintained during construction, and a temporary erosion and sedimentary control (TESC) plan, as a part of the Best Management Practices (BMP) must be developed and implemented as well. The TESC plan should include the use of geotextile barriers (silt fences) along any down-slope, straw bales to de- energize downward flow, controlled surface grading, limited work areas, equipment washing, storm drain inlet protection, and sediment traps. Also, vegetation clearing must be kept very limited in this site to reduce the exposed surface areas. A permanent erosion control plan is to be implemented following the completion of the construction. Permanent erosion control measurements such as establishment of landscaping, control of downspouts and surface drains, control of sheet flow over the final slope grades, prevention of discharging water over the final slopes and at the toe of the slope are to be implemented following the completion of the construction. 5.8.2 Seismic Hazard Structural design of the buildings at the project site should follow 2003 International Building Code (IBC) standards. Based on our evaluations of the subsurface conditions and review of Table 1615.1.1 of IBC,we interpret the underlying bearing soils to correspond to `C',which refers to very dense soils. According to the IBC standards, the mapped spectral response accelerations SS= 1.5 and S1 = 0.5, and corresponding site co-efficient values Fa = 1.0 and F„ = 13, respectively, should be used for the design of the buildings. As part of the seismic evaluation of the site, the liquefaction potential of the site was also evaluated. Liquefaction is a phenomenon, which takes place due to the reduction or complete loss of soil strength due to increased pore water pressure during a major earthquake event. Liquefaction primarily affects geologically recent deposits of fine-grained sands that are below the groundwater table. Based on the soil and groundwater conditions, it is our opinion that the on-site soils are not prone to liquefaction, ga A��`Pacific Geo Engineering �.�. G ...e.a,.,.,..a..�,..�.�..�,,..�,..� Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 19 therefore, potential for widespread liquefaction and its associated hazards over the site during a seismic event is none. Therefore, subsurface conditions do not warrant additional mitigation techniques relating to seismic hazards. 5.8.3 Landslide Hazard Evaluation The subject site is a relatively level ground with some minor undulations, therefore, landslide hazard is not expected in this site. 5.9 Infiltration PotenHal Evaluation The native soils encountered in the subject site are considered good permeable soils, therefore should be considered conducive for installing the proposed infiltration storm tract. The infiltration potential of the native sands in the proposed storm tract area was evaluated by performing several field percolation tests in test pit TP-1, TP-2, and TP-7 at 4 feet depths below the existing grades following the EPA Falling Head Permeability Test method described in Pierce County Stormwater Design Manual. The average permeability value found from these tests is 12 inches/hr. A factor of safety value of 2 must be used to determine the design infiltration rate. It should be noted that the operational verification testing of the permeability of the native soils must be done in the proposed storm tract area during the construction of the pond. 6.0 REPORT LIMITATIONS The conclusions and recommendations presented in this report are based on a site reconnaissance, a subsurface exploration program, review of pertinent subsurface information, the preliminary design information provided by Larson and Associates, and our understanding of the project. The study was performed using a mutually agreed-upon scope of work. It should be noted that PGE cannot take the responsibility regarding the accuracy of the test pit locations plotted on the attached Site and Soil Exploration Plan prepared by the other consultant. If any of the information considered during this study is not correct or if there are any revisions to the plans for this project, PGE should be notified immediately of such information and the revisions so that necessary amendment of our geotechnical recommendations can be made. If such information and revisions are not notified to PGE, no responsibility should be implied on PGE for the impact of such information and the revisions on the project. �� PGEPaciFc Geo Engineering .i.mae�,�w,..+�a.a.�,�u,..aw.+..� Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 20 Variations in subsurface conditions may exist between the locations of the explorations and the actual conditions underlying the site. The nature and the extent of the subsurface variations may not be evident until construction occurs. If any subsurface conditions are encountered at the site that are different from those described in this report, we should be notified immediately to review the applicability of our recommendations if there are any changes in the project scope. This report may be used only by the client and for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both off and on-site), or others factors including advances in our understanding of applied science, may change over time and could materially affect our findings. Therefore, this report should not be relied upon after 24 months from its issuance. PGE should be notified if the project is delayed by more than 24 months from the date of this report so that we may review to determine that the conclusions and recommendations of this report remain applicable to the changed conditions. The scope of our work does not include services related to construction safety precautions. Our recommendations are not intended to direct the contractors'method,techniques, sequences or procedures, except as specifically described in our report for consideration in design. Additionally, the scope of our work specifically excludes the assessment of environmental characteristics, particularly those involving hazardous substances. This report including its evaluation, conclusions, specifications, recommendations, or professional advice has been prepared for planning and design purposes for specific application to the proposed project in accordance with the generally accepted standards of local practice at the time this report was written.No warranty, express or implied, is made. This report is the property of our client Mountain Terrace Builders, LLC, and has been prepared for the exclusive use of our client and its authorized representatives for the specific application to the proposed development at the subject site in Yelm,Washington. It is the client's responsibility to see that all parties to this project, including the designer, contractor, subcontractors, etc., are made aware of this report in its entirety. The use of information contained in this report for bidding purposes should be done at the contractor's option and risk. Any party other than the client who wishes to use this report shall notify PGE of such intended use and for permission to copy this report. Based on the intended use of the report, PGE may require that additional work be performed and that and updated report be reissued. Noncompliance with any of these requirements will release PGE from any liability resulting from the use this report. � P/'��PaciFc Geo Engineering V .i..e.a.,xs�ra,oru.ao.aN...w.m..en... Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 21 7.0 ADDITIONAL SERVICES As the geotechnical engineer of record for the proposed development,PGE can perform a review of the project plans and,specifications to verify that the geotechnical recommendations of this report have been properly interpreted and incorporated into the project design and specifications. PGE can also provide geotechnical consultation, material testing, and construction monitoring services during the construction phase of the project. These services are important for the project to confirm that the earthwork and the general site development are in compliance with the general intent of design concepts, specifications, and the geotechnical recommendations presented in this report. Also, participation of PGE during the design and the construction phases will help PGE engineers to make on-site engineering decisions in the event that any variations in subsurface conditions are encountered or any revisions in design and plan are made. 8.0 GEOTECHNICAL SPEICAL INSPECTIONS Pacific Geo Engineering (PGE) recommends that the following geotechnical special inspection services to be performed during the construction of the proposed development. According to PGE, the following items should be considered as a minimum but not limited to. • A professional geotechnical engineer should be retained to provide geotechnical consultation, material testing, and construction monitoring services during the construction of the project. • A pre-construction meeting should be held on-site to discuss the geotechnical aspects of the development and the special inspection services to be performed during the construction. • The site preparation activities including but not limited to stripping, cut and filling, final subgrade preparation for foundation, floor slab, and pavement be monitored by a geotechnical engineer or his representative under the engineer's supervision. • A list of the possible items that require special geotechnical inspection and approval by the geotechnical engineer is as follows: 1. Stripping of topsoils. 2. Removal of unsuitable soils. 3. Proofrolling of any exposed subgrades that are intended to provide direct support for new construction and/or require new fills. 4. Any structural fills to be used in this site, and structural fills placement and its compaction. 5. The temporary or permanent excavation inclinations and excavation stability. 6. The footing bearing materials, bearing capacity value, and the embedment depth of the footings prior to placing forms and rebars. 93 /'��!�►�Pacifc Geo Enginee�ing /"y ..�.a,�,.�.�..�,�.�,..�.,..a.,.�.,. Geotechnical Engineering Study Yelm Aparhnents Project No. 13-420 September 23,2013 Page 22 7. Subgrade preparation for soil supported slab-on-grade floors. 8. Subgrade preparation for driveways and pavements. 9. The compaction of the CSBC, CSTC,and the asphalt layers in driveways and pavements. 10. The backfilling and its compaction, and drainage behind the retaining walls. 11. The installation of drainage systems such as footing excavation drain and footing drain,and daylighting of such drains and downspout or roof drains. 12. Bedding and the backfilling materials, and backfilling of utility lines. 13. The verification of the presence of the intended infiltrative soils at the bottom of the infiltration pond and the verification tests of the design infiltration rates of the infiltrative soils,and the installation of the infiltration systems. 14. Buffer distances from the vegetation clearing limit and the vegetation clearing limit. 15. The installation and functioning of the temporary and permanent erosion and sedimentation control plan. 16. The development consideration and construction limitations mentioned in this report. 17. Any other items specified in the approved project plans prepared by other consultants relevant to the geotechnical aspect of the project. � Ol ,` �� M �C C � W O � � �" � k w V 4 � � ' � � � � H � rn ,� ' z °�' ° � w :� � � v H � °. 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Content% 0— 12" Top soils: Brn., Silty Sandy gravelly Soils w/ roots and organics,Sl.Moist,Loose 12"—24" GP Brn., Silty Sandy Soils w/ abundant Gravels & TP-1 1.3 Cobbles, some roots and organics, Sl. Moist, S-1 @ 1.S Loose 24"—11' GP Gray Sand w/ trace Silt, & abundant Gravels, TP-1 0.7 Cobbles,Boulders,Sl.Moist,Med.Dense S-2 @ 4' Note: Test pit was terminated at approximately 11 feet below the existing ground surfaces. No groundwater or seepage was encountered within the exploration depth. No signs of mottling were noticed within the exploration depth. Slight caving was noticed within the upper 24"depth,and severe caving in the remaining depth. Field percolation tests were performed @ 4'below ground surfaces in Test Pit 1,2,and 7. Percolation rates,K�12"hr. !� G�t'Y o� `�wv� FACILITY SUMMARY FORM Complete one (1) for each facility on the project site including flow control and water quality treatment facilities (BMPs) such as, but not limited to: detention ponds, vaults, or tanks; infiltration ponds, trenches, swales, or vaults; bioretention facilities (rain gardens, bioretention swales/slopes); biofiltration BMPs (filter strip, biofiltration swale); oil/water separators; wet ponds; constructed wetlands; dispersion areas & flow spreaders; StormFiltersT"'I & other proprietary devices; sand filters; etc. Attach 8 1/2 x 11 sketch showing location of facility. Applicant may prepare one copy of pages 1 to 4 for the project and then attach multiple copies of pages 5 &6 for each separate facility. Facility Name or ldentifier(e.g.,Pond A): ��I t=�L-_(LF�TT�� TfL�;SG}� Total Number of Facilities Associated with Project: � � ) (For which a Faciliry Summary Form is being prepared) Name of Road or Street to Access Facility: tic��-1��-2� �T, Name of Nearest Major Cross Street: Wu��T-'��/�j'F�R`C uQI.VC`'� p�-. Hearings Examiner Case Number: Z��3�32� L'Z'C`t Ot' `��M Tlr�rrstvn-E�e�nat�Project No./Bldg Permit No.: _ Parcel Number(s): ZI�ZL(�-{ 1 OZbC� „ �� ; ,�h� .�j g � ��,* �� e �i ��" � ��'e �aj x ,� �p�� . + .��.a»�,'�;�.:.�.. ` ' �! .,«f'. � ��:c - . -�.:��, .. ... ...,_. „ .�.. � cn,,, �-. , w,��.-�°..�' �;, 8„a.�. � � e To be completed by Utility Staff: Utility Facility Number Project Number(num) Parcel Number Status,(num, lch) (0,Known; 1,Public;2 Unknown;3,Unassigned) Basin and Subbasin: (num,6ch) (2ch for basin, 2ch for subbasin, 2ch future) ,:, .�'..�� . �y x4 x�'a�.��, �. ? w�� ;2 '��x "�_;��"F'y,P��%� „��.< N k :�' .�, r p :�. .�"�..�,. � ,�,..�!�:,, i,Y � ,�F�' . , ...�.fL'. �„ /��Fa.ti" ..,, r,�`gi,., .,,.'V�� Y''��Vi/n,�r .9,/! r' � Part 1 -Proiect Name and Proponent Project lvame: fZ=�/r=oZ ��1 �t�i�C,1M.��'S Project Owner: �T• �CZ��C� �lJ.�l�-��Z.� Project Contact: T6�-►`C �1��•�11� Thurston County Facility Summary Form Page 1 of 6 ! / Address: �sZ.�{ GR-o�M.W�LV ��-1 �CLLV� 1-Jl� �S6 �2�2�U.��,��3��j Phone: ZS 3- 31 a - SDT7 f3 Project Proponent: (if different) SAV�� Address: Phone: Project Engineer: �TZf�4-1 1 S. VJ1Z1�I�'C►b 1--1 � I��. Firm: ��JOb-� � f 1S�%�S r �C,• Phone: Zs3-�f7'-�-3�U'� Part 2-Proiect Location Section 2-4 Township �� Range � � Names and Addresses of Adjacent Property Owners: (attach add'1 sheet if required) �g� �rTP�� Part 3-Tvpe of Permit AAUlication Type of permit(e.g.,Building,Plat,etc.): S�TE- ��VE l�i�IM.��'1��-'�l��s�� Other Permits(circle) WDFW HPA COE 404 COE Wetlands DOE Dam Safety FEMA Floodplain Shoreline Mgmt Rockery/Retaining Wall Encroachment Grading NPDES Construction Storm NPDES Industrial Forest Practices/Clearing Other Page 2 of 6 Thurston County Facility Summary Form 1oa Other Agencies (Federal, State, Local, etc.) that have had or will review this Drainage and Erosion Control Plan: Part 4-Proposed Proiect Description What stream/lake/saltwater basin is this project in (e.g., Salmon,Green Cove,Woodland): Project Area,acres(total area of all parcels) `,`Y"��, Project Area Disturbed,acres(total of all areas disturbed by project) � ��y�� (Include all area cleared, graded, etc. as part of this project) Onsite Impervious Surfaces: (excluding offsite public/private street frontage). Existing Impervious Surface,acres: �l� Replaced Impervious Surface,acres: �! Q Existing Impervious Converted to Landscape,acres: �/Q New Impervious Surface, acres: ��D°1Z� Total Impervious,acres(existing,new,and replaced): ��D�'C� Zoning: �"�� Onsite: Residential Subdivision: Number of Lots: �r� Lot size(average),acres: Building Permit/Commercial Plat: Building(s)Footprint,acres: ��1''� Concrete Paving,acres: D�y3S Gravel Surface,acres: Nl-� Lattice Block or Porous Paving,acres: �� New Public Roads(including gravel shoulder), acres: �/�1 New Private Roads(including gravel shoulder),acres: u/� Thurston County Facility Summary Form Page 3 of 6 (b� Frontage Improvements(including gravel shoulder),acres: d�� Existing road frontage to center of right-of-way,acres: �• � +(� Part 5-Pre-Developed Proiect Site Characteristics Stream through site,y/n: � Name• �"�I A DNR Type: u�� Type of feature this facility discharges to(i.e.,lake,stream,intermittent stream,pothole, roadside ditch,sheet flow to adjacent private property,etc: C7�?au.�tDW.�T'�Q� Swales,Ravines,y/n: � Steep slopes,(steeper than 15%)y/n: � Erosion hazard,y/n: N (soil types classified "highly erodible"by NRCS soil survey) 100 yr. Floodplain,y/n: � Lakes or Wetlands,y/n: ^' Seeps/Springs,y/n: �'-� High Groundwater Table,y/n: T" (depth to seasonal high groundwater table Zess than S feet) Wellhead Protection or Aquifer Sensitive Area,y/n: � Other: Page 4 of 6 Thurston County Facility Summary Form SOZ Part 6-Facilitv Description Facility Type: �1-��1.-T12.�►1'LA� �"�h-�� Facility Description: Total Area Tributary to Facility Including Offsite(acres): 0�T�✓ Total Onsite Area Tributary to Facility(acres): G• 3�J Design Impervious Area Tributary to Facility(acres): d•�35 Design Landscaped Area Tributary to Facility(acres): �ffl Design Native Vegetation Area Tributary to Facility(acres): �-A Design Total Tributary Area to Facility(acres): d��35 Water Quality Design Volume: Water Quality Design Flow: b•0� 100 Year return interval,24-hr Design Flow: Part 7-Release to Groundwater(if applicable) Design Infiltration Rate �4 in/hr r � Average Annuai Infiltration per WWHM ��T�L Q-�� vb�� S �� = J�2 ��,^� Designed for 100% Infiltration Y/N: _�_ Designed for Infiltration Treatment Y/N: N Part 8-Release to Surface Water(if applicable) Dischar e Structure: check all that a ply) �� g ( P Single orifice Elev. Dia. Multiple orifice Elev. Dia. lev.2 Dia. Elev.3 Dia. Weir Elev. Type Thurston County Facility Summary Form Page 5 of 6 (63 Overflow Weir Elev. Dia/Width: Spillway Elev. Max Elev. Pump(s) ModeUType: R ing: Other Discharge to surface water: �� Return Period Pre Developed: Post Dev o ed: 2 year: 5 year: 10 year: 25 year: 50 year: 100 year: Pond Information: Design Max surface water elev tion: ft(msl) Design Maximum pond dep : ft Pond Volume at Max de gn water level: cubic feet Overflow water eleva on: ft(msl) Sediment storage v lume: ft(depth below outlet) Page 6 of 6 Thurston County Facility Summary Form �b�{ Thurston Geodata Center - Parcel Search Page 1 of 3 ` � � �� .��":��,� . .�: �; ��.�+�.-� `�;� �� Data for Parcel No. 34250000800 Zoom Map to Parcel Google Ear�h �need to have Google Earth installed an you system} Gc�ogle Maps Virtu�l Earth 4'(��se t��a(��.: ;.��.€=i� t�� Z�:.11.) i��r l?.l`lYr1 .1►[`�C.`1..�I��1�:1? ��r•it:ji°tf� �rtili��r�4,�: ��r ��-�l;��it� t��r t•ese��.C� View Assessor's Data #or Parcel Owner(s): GORE ELIZABETH S Address: PO BOX 4027 City: TENINO State: WA, 98589-4027 Parcel No.: 34250000800 Site Address: 15346 TO 15348 BERRY VALLEY DR SE Site City: YELM Site Zip: 98597 Section: S24171 E Abbreviated Legal: BERRY VALLEY ESTATES LOT 8 Usecode: 12 Tax Code Area: 170 Taxable: Yes Annual Tax: View Property Taxes for Parcel Property Type: MUL Total Acres: 0.18 Land Value: View Assessor's Data for Parcei Building Value: View Assessor's Data for Parcei Total Value: View Assessor's Data for Parcel Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT Flood of 1999: Unknown l b'� http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=34250000800 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 �- � '.�.-��`�'i�+�?� : � ��. �E.�� :.v�.: A�� Data for Parcel No. 34250000200 Zoom Map ta Parcel Google Earth (need to have �oogle Earth installed on you system) Google Maps Virtuaf Earth 1'[4a�:�•;: t��t�!�� b�°�.: t<� 1�.��:-11) �}c��• I.)r�"[ :� ()I`�C.'I,:�.�i�-1}�:fZ ��:�,� tt} i�t3li�i4�<�; �>��r ��-�:��ti: ic�r t'i:S's',t'ti"t�l View Assessor's Data fior Parcel Owner(s): GORE ELIZABETH S Address: PO BOX 4027 City: TENINO State: WA, 98589-4027 Parcel No.: 34250000200 Site Address: 9909 TO 9911 LONGMIRE ST SE Site City: YELM Site Zip: 98597 Section: S24171 E Abbreviated Legal: BERRY VALLEY ESTATES LOT 2 Usecode: 12 Tax Code Area: 170 Taxable: Yes Annual Tax: View Property Taxes for Parcel Property Type: MUL Total Acres: 0.19 Land Value: View Assessar's Dat�for Parce! Building Value: View Assessor's Data for Parcel Total Value: View Assessor"s Data for Parcei Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT Flood of 1999: Unknown i�� http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=34250000200 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 �� Data for Parcel No. 34250000100 Zaom Map to Parcel Google Earth (need to have Gaogle Earth instailed on you system) Google Maps Virtual Earth C'1<;�s� ��;� ��°� tt� ��>:-�1.:) ��?r I:)��.�'F� I�I��"1,.-lI?0-1��-[Z ��°i�}3� ts> ��ti'E€r��>: ��t�� i�,-��it�:: 1'��r r°c:s€;��ru� View Assessor's Data for Parce! Owner(s): GORE ELIZABETH S Address: PO BOX 4027 City: TENINO State: WA, 98589-4027 Parcel No.: 34250000100 Site Address: 9901 TO 9903 LONGMIRE ST SE Site City: YELM Site Zip: 98597 Section: S24171 E Abbreviated Legal: BERRY VALLEY ESTATES LOT 1 Usecode: 12 Tax Code Area: 170 Taxable: Yes Annual Tax: View Property Taxes far r^arce! Property Type: MUL Total Acres: 0.33 Land Value: View Assessor's Data for Pareel Building Value: View Assessor's [�ata for Parcel Total Value: View Assessor's Data for Parcel Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT Flood of 1999: Unknown �0�1 http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=34250000100 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 ��.�`��. .:; �� .�� :.: � �..��x�� Data for Parcel No. 21724440200 Zonm Map to Parcel Google Earth {need to have Gaogle Earth installed on you system} Google Maps Virtual Earth I'1�;�5� ��t�� 5��°� tt� (��:<"�1.) t��[�:'� 6�r1 [:)l��;l:;111�-1�:?I� �,�.ii�s° tf, titi[ari�� r ��;��it� P��r �-�s�G��•cl� � View Assessc�r's Data for Parcel Owner(s): BROOKDALE GOLF LLC Address: 1802 BROOKDALE RD E City: TACOMA State: WA, 98445 Parcel No.: 21724440200 Site Address: 15425 MOSMAN AVE SW Site City: YELM Site Zip: 98597 Section: S24171 E Section 24 Township 17 Range 1 E Quarter SE BLA- 1142 PTN TR B Document 11/489 FOR TAX Abbreviated Legal: PURPOSES ONLY (OTHER PTN 21725110400 NOT IN OPEN SPACE OPEN SPACE) EX PTN PER ROW AFN 3975434 Usecode: 94 Tax Code Area: 170 Taxable: Yes Annual Tax: View Praperty Taxes for Parcei Property Type: GLF Total Acres: 75.75 Land Value: View Assessor's Data for Parcel Building Value: View Assessor's Data for Parcel Total Value: View Assessar's €�ata for Parcei Current Use: Y Exemptions: None �0� http://www.geodata.org/website/cadastral/resultsparcel.asp?parcel=21724440200 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 � ��,��"`�►�.�.�� '':. �� -� . �� Data for Parcel No. 21724410302 Zaam Map to Parcel GoogEe Earth (need to have Googie Earth installed on you system) Gc�ogle Maps Virtuai Earth �'1c:t�� t?�t�� r� tct ��:,-�I) ��u��l);�."1 .1 ()I`�('I_.�(�-1��Z ��r°ii>�• ti> ��til�:�in� c��ir ��:l��it�: ['�}r �°�°:�::��•i:�� View Assessor's Data for Parcel Owner(s): ORCHARD APARTMENTS LLC Address: 4210 36TH AVE NE City: OLYMPIA State: WA, 98516 Parcel No.: 21724410302 Site Address: 501 MCKENZIE AVE SW Site City: YELM Site Zip: 98597 Section: S24171 E Abbreviated Legal: 24-17-1 E NE-SE COM NLY COR B6 SOLBERGS 1 ST N53-30F30-W 50F TO POB Usecode: 13 Tax Code Area: 170 Taxable: Yes Annual Tax: View Praperty Taxes far Parcel Property Type: APT Total Acres: 1.15 Land Value: View Assessor's Data for Parcel Building Value: View Assessor's Data for Farcel Total Value: View Assessar's Data for Parcel Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT IawO http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410302 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 �� a�"'+f� ��.�, �� Data for Parcel No. 21724410600 Zoom Map tn Parcel Google Earth (need to have Gaogle Earth installed on yt�u system) Google Maps Virtual Earth �'1�$�5�r��E�k�. s��°� t�� Zt-:�'��) c?u�-I:).-�C:� .I��`�C'l,.�l?�-t1:I� �-sric��• tf> trii:lir.lr��,,� c��ar t.�-�:1��:ite 4��r �i:sc;z��c�� View Assessor's Data for Parcel Owner(s): ROBERTSON JEFFREY D & KATHRYN M Address: 1143 W ROANOKE ST City: CENTRALIA State: WA, 98531 Parcel No.: 21724410600 Site Address: 307 SOLBERG ST NW Site City: YELM Site Zip: 98597 _ Section: S24171 E Section 24 Township 17 Range 1 E Quarter NE SE Abbreviated Legal: SS-8037 LT 1 Document 025/409 And for appraisal purposes only SS-8037 LT 2 Usecode: 13 Tax Code Area: 170 Taxable: Yes Annual Tax: View Praperty Taxes for Parcel Property Type: APT Total Acres: 0.78 Land Value: View Assessor's Data for Parcel Building Value: View Assessor's Data for Parcel Total Value: View Assessor's Data for Parce! Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT ��L http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410600 11/27/2013 Thurston Geodata Center - Parcel Search Page 1 of 3 �� , �' �:� ��.� ��- �. ,_; ' Data for Parcel No. 21724410600 Zoom Map ta Parcel Google Earth (need to have Google Earth installed on you system) Google Maps Virtua! Earth l'1�:a�:��: �7�a1�� t�t°�: t�� }:.-�1:) f}�r I),� � :"� I)I�t.'�..-�E��l�:�� °i��$• t�� s€ili:�� c��zr ��.l�sitc. f't�r �•�s��•�;�� View Assessor's Data for ParceR Owner(s): ROBERTSON JEFFREY D & KATHRYN M Address: 1143 W ROANOKE ST City: CENTRALIA State: WA, 98531 Parcel No.: 21724410600 Site Address: 307 SOLBERG ST NW Site City: YELM Site Zip: 98597 Section: S24171 E Section 24 Township 17 Range 1 E Quarter NE SE Abbreviated Legal: SS-8037 LT 1 Document 025/409 And for appraisal purposes only SS-8037 LT 2 Usecode: 13 Tax Code Area: 170 Taxable: Yes Annual Tax: View Property Taxes for Parcef Property Type: APT Total Acres: 0.78 Land Value: View Assessar's Data for Parcel Building Value: View Assessor's Data for Parcef Total Value: View Assessor's Data far Parcel Current Use: N Exemptions: None Wetlands: Unknown Floodzone: OUT 111 http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410600 11/27/2013 r/x llw 1�'o vtof-o tai w - � � ,. `" �°"°.,,�." �1�P�I�N'1 133 HS 2d3/�O� �� ow HQ � � z �'�"� 'I' 0 U a O w � �� ` OW � ��J�i5�1� ��'��fi � ¢�� ¢� � N� � �=!iEl��3E.�: �� . ��. � ��3��yFF� #�i I}}• •I* �� gT€�,NoS�; �Ji�� I � { i 1 ; � e� � �� , , , � � ��, " � .�'.i �� ---�--'� �'`. � � I �P 8 j. �� ` � ��k 3 I � � ' n I k � �.< � ��u �€ � � u! x I �� `,�� ' � ��a � �� I " I � ' � � �� $� � � � , ta: � 3�.. ;.a : 4 O �Y� g��y6��y■� � � � � �•,�� ..,�.V �. 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