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20130320 Prelim Storm Drainage Report 08302013 � � S I Larson 8z Associates Land Surveyors&Engineers,Inc. 4401 South 66th Street Tacoma,WA 98409 $° v 3 � y„ �- � �- � � , ,; �- ;: � �� /k e,d � E �Et y b � �� 4 €" � `i, ' . : � ! � } � / � � � E � � �• ��' S 5, b d [� ��r...r.... w.n..... r.,.,e ...... ,... .::.,..� �„i.., r.�... .... ... .«�. ...,..,. . ..� -......,,�.. ; ...rs..,., C ,s�i� � .,.,.<,i...... . ...:..,, e. ..n...,r 't .n....< .. CONCEPTUAL STORM DRAINAGE REPORT PROPONENT: Mt. Terrace Builders Contact: Tony Trunk 6524 Cromwell Beach Drive N.W. Gig Harbor, WA. 98335 Ph: (253) 310-5078 �•��3 MID, i �� oFBw�s �� , j � � O .� �� ,� � I : � z: � $ �� . �: .�. i � �,� �;5�y��GISTER��4't�,� _' II� WIONAL E� �� _ _- - _. . _ _ _ \��\\V�� PREPARED BY: Larson & Associates Land Surveyors and Engineers, Inc. 4401 South 66t'' Street Tacoma, WA 98409 (253) 474-3404 August 29, 2013 f t s E �.�..�,. . `..i� .F�.�� ...,- .,� '# ... �., �. � �.�s�� '�� PROJECT ENGINEER'S CERTIFICATION.........................................................................................................1 DRAINAGE REPORT SECTION 1-PROJECT OVERVIEW.............................................................................................................................2 SECTION 2-EXISTING CONDITIONS SUMMARY........................................................................................................3 SECTION 3-OFF-SITE ANALYSIS REPORT.................................................................................................................3 SECTION 4-PERMANENT STORMWATER CONTROL PLAN......................................................................................3-4 SECTION S-CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN.........................................................4-E SECTION 6-SPECIAL REPORTS AND STUDIES...........................................................................................................6 SECTION7-OTHER PERMITS...................................................................................................................................6 SECTION H-OPERATION AND MAINTENANCE MANUAL............................................................................................C SECTION9-BOND QUANTITIES ...............................................................................................................................6 INFILTRATION FACILITY SIZING UTILIZING MGS FLOOD MODELING.........................................7-16 APPENDIX.......................................................................................................................................................... 17-37 VICIriITYMAP ................................................................................................................................................ 18 SITEINFORMATION................................................................................................................................... 19-21 AQUA SWIRL MAINTENANCE&I]vSPECTION MANUAL ..................................................................22-37 � r , m �•� �. �.....:� u.,..,.n� „.��e�:��,..�� a: �, �. �W�� , g,fbj:,� �� ...,��+,�i..��,�� ..� y I hereby state that this Conceptual Storm Drainage Report for Yelm 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. � Grant J. Mi �e on, P.E. '��,1 �• S.MIDjj �1 � �� e � �� . .. � . � , • T� w_.,� ', , � 4'. c�, s o j�. �" .� 2 �Y / � � `�� / .� � : . � . r .�• . w ,, S�GIS R�91 -� SI�NAL�*?1 • I,�\\\\��, f 1 � � ¢ _<. ,....,��..,A._ ,_ ."..� _„ �.��„ ...,,.,,. � ,�,,,..:uE .. . 4 ' ,> . . . ,„„ . ,..,. .� �....�,.�,� � �•...,..�.. ...„�,. S��IQI� � —PR4JE�T C}�E1�.�IE� The"Yelm Apartments"proj�ct is located in the NEl/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 0�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#1: Preparation of Stormwater Site Plan(This document satisfies this requirei�nent) Minimum Requirement#2: Construction Stormwater Pollution Prevention(SWPPP) (This separate document w�ll be completed at Final Engineering stage) Minimum Requirement#3: Source Control of Pollution (This information will be provided at Final Engineernng stage) Minimum Requirement#4: Preservation of Natural Drainage Systems and Outfalls (See Sectio�4 of this_report which discusses how we meet this rec�i.��re�x��t) _ Minimum Requirement#5: Un-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 (This will be completed/addressed at Final Engineering Stage) All of these requirements will therefore be addressed throughout this report and on the attached Conceptual Site Plan. '1.. r , SE�TI�I� �-E�ISTING CQNDITICIN� SUIYIMARY 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. SE��l� �►—QFF-SITE ANA.LYSTS REFC)RT 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. SE��`�QN 4—�ERMANENT STQRMWATER CUNTRC}L FLAN � SUB-SECTION 1 —EXISTING SITE HYDROLOGY As previously discussed, the site is located east of the intersection of Longmire St. SE ° and Berry va��;r�:. T'�e proje�t a�•��i� iurrently vacant l�id a��i siu��rr�n� 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. T'he 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—DEVEY.OPED 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 3 � + 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. 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 runoff. We are in the process of performing additional soil testing onsite to validate infiltration rates but our design has been conducted based off a design rate of 20 in/hr which was determined from previous soil investigations conducted onsite. 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). SUB-SECTION 6—CONVEYANCE SYSTEM ANALYSIS AND DESIGN The conveyance system will be sized to accommodate the 25-year/24 hour developed storm event. These calculations will be submitted with the final engineering documents. SE�`T`IE}N �—G(.�k�TSTR.UGTIa►N STQRMV�ATER PQLLUTTQN PREVENTION FLAN 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. � f � 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. SE�Tkf�N �—Sg�CIAL REPU�2.TS AND STiT1�IES 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. ��TI�I� �—f.?T�IER PERIYII'�"S 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 �E�`TIQkI� S—QFERATIQN Ai�TD MAINTEN.AN�E MANUAL This will be completed/address at the Final Engineering Stage. SECTI�N 9—BE�ND QUANTITTES WQRT�SHEET Not applicable at this time. �o , , INFILTF:ATIUl�T FACILITY SIZING �,ARS�N AND ASSOCIATES, INC. LAND SURVEYORS & ENGINEERS 4401 SOUTH 66TH STREET TACOMA, WA 98409 ; � , , '�►S�l.'S'�A"t'S�� '��h1 �'-v=Z��-!(7 F'dF� Ru►-toF'F � �a�i-r��8 '� K KT.�1� t..o-t— A r��5 e S i MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: OS/29/2013 12:55 PM Input File Name: Yelm Apartments Infiltration Trench.fld 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 Fo�ect 0.000 Till Pasture 0.000 ! Till Grass 0.000 Outwash Forest 0.420 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 0.000 Impervious 0.000 ---------------------------------------------- Subbasin Total 0.420 ----------------------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 �r,,,,., o.,,,f n nnn � , User 0.000 ' Impervious 0.420 ---------------------------------------------- Subbasin Total 0.420 ************************* 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 : Trench at Toe of Embankment Trench Length (ft) : 40.00 Trench Width (ft) : 4.00 Trench Depth (ft) : 4.00 Trench Bottom Elev(ft) : 100.00 Trench Rockfill Porosity(%) : 30.00 Constant Infiltration Option Used Infiltration Rate(in/hr): 20.00 ****************'`*****FLOOD FREQUENCY AND LIURATION 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): 185.49 Total Runoff Infiltrated (ac-ft): 185.49, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% c� � . ***********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 8.241 E-05 2-Year 3.735E-06 5-Year 8.413E-05 5-Year 7.033E-06 10-Year 8.457E-05 10-Year 9.072E-06 25-Year 1.959E-04 25-Year 1.316E-05 50-Year 3.886E-04 50-Year 1.646E-05 100-Year 6.011 E-04 100-Year 1.822E-05 200-Year 1.082E-03 200-Year 0.046 *" Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance According to IDept. of Ecology Criteria**** Excursion at Predeveloped %ZQ2 (Must be Less Than 0°/a): -100.0% 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): -87.3% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS ------------------------------------------------------------------------------------------------- POND MEETS ALL DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- 1� �11F'L�•'C�t.pR'Z�►.1 �^.�-tC� �Z�►..Sd fir�t�. A'Pp►tl-T++�l$y.tT ''� ' ' B�t—VS�� MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: 08/29/20131:13 PM Input File Name: Yelm Apartments BLDG. trench.fld Project Name: Yelm Apartments Analysis Title: Building Infiltration Trench (both buildings to trench) Comments: PRECIPITA1fION 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)-------- Til! F�rest 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 �� r=r�� o��F n nnn � 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 Infilt Trench Lnk1 Link Type: Infiitration Trench Downstream Link: None Trench Type : Trench at Toe of Embankment Trench Length (ft) : 20.00 Trench W idth (ft) : 4.00 Trench Depth (ft) : 4.00 Trench Bottom Elev(ft) : 100.00 Trench Rockfill Porosity(°/a) : 30.00 Constant Infiltration Option Used Infiltration Rate(in/hr): 20.00 ******"**"*******'"***'`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°/a Total Runoff Filtered (ac-ft): 0.00, 0.00% Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% (2 � , ***********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 2.278E-06 5-Year 3.504E-05 5-Year 4.940E-06 10-Year 9.381 E-05 10-Year 6.379E-06 25-Year 3.632E-04 25-Year 1.021 E-05 50-Year 8.479E-04 50-Year 1.283E-05 100-Year 9.605E-04 100-Year 1.330E-05 200-Year 1.842E-03 200-Year 1.760E-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 '/�Q2 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°/a PASS ------------------------------------------------------------------------------------------------- POND MEETS ALL DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- 1'� ��y�-tti2.F�T�Go4.1 �JG-� Ss1-Z►-1C7 �ot�- C�vE�ZL�►p' ' ' �A2.�C,.�- S"�t�.v�G't'Lx2�. MGS FLOOD PROJECT REPORT Program Version: MGSFIood 4.12 Program License Number: 200810005 Run Date: 08/29/2013 12:56 PM Input File Name: Yelm Apartments Covered Parking Trench.fld Project Name: Yelm Apartments Analysis Title: Covered Parking Infiltration Trench Comments: PRECIPITA�'ION INPUT Computational Time Step(Minutes): 60 Extended Precipitation Timeseries Selected Climatic Region Number: 14 Full Period of Record Available used for Routing � Rrecipitation 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)-------- Til9 Ferest Q.QQO _ , Till Pasture 0.000 Till Grass 0.000 Oufinrash Forest 0.045 Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 0.000 Impervious 0.000 ---------------------------------------------- Subbasin Total 0.045 ----------------------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 r_.,,,,,, o..,,f n nnn � User � 0.000 Impervious 0.045 ---------------------------------------------- Subbasin Total 0.045 *************************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 : Trench at Toe of Embankment Trench Length (ft) : 15.00 Trench W idth (ft) : 3.00 Trench Depth (ft) : 3.00 Trench Bottom Elev(ft) : 100.00 Trench Rockfill Porosity(%) : 30.00 Constant Infiltration Option Used Infiltration Rate(in/hr): 20.00 "******"*****'`'`****"**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 Infi�t Trench Lnk1 "`**""**"** Infiltration/Filtration Statistics-------------------- Total Runoff Volume(ac-ft): 22.26 Total Runoff Infiltrated (ac-ft): 22.26, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% �� *********'"*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 8.940E-06 2-Year 1.509E-07 5-Year 9.063E-06 5-Year 1.509E-07 10-Year 2.426E-05 10-Year 1.509E-07 25-Year 9.392E-05 25-Year 1.509E-07 50-Year 2.193E-04 50-Year 1.919E-07 100-Year 2.484E-04 100-Year 2.986E-07 200-Year 4.765E-04 200-Year 1.950E-06 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance According to Dept. of Ecology Criteria**** Excursion at Predeveloped '/2Q2(Must be Less Than 0%): 0.0% PASS Maximum Excursion from 'hQ2 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 ------------------------------------------------------------------------------------------------- ICo i ' � � � � , � � �.:.. �,,,,.,. �: � � � � � � � � � � � � „ �° � ,,. t. � � � �, �H �,�.: � � � � � � �:, ,.� ,� � � � � � " � �'� _ � � � L x � � � ,�;, �. _ fl ....,,H.....:�. ,,.. .,, .� ,.w.:.:;,,..,rr> e.,,,...., ... - . ' . , _ „ .�.,,,,:;.,_.... , , , ,,,,:. ;,: . .,,.,;:,;, '� ,:.�.. . i ,�._". . . . i .. � . . � . . . ' . . � � � � � - � . . . . . i � LARSON AND ASSOCIATES " LAND SURVEYORS & ENGINEERS, INC. i � 4401 SOUTH 66TH STREET , ' TACOMA, WA 98409 � i �� , ��T„Y ��1 of 1 � � � � �° �� : ��.� � „ v. �x�F` �e,..�rcrvA�s�� s��. �� `b�g��(�J�y��br, i� �� a 1{,, ' ... _ `� �..�,�. � h�s� � �� °�� ,� ', �g �,aia � . �� M�, ,�` .: : ��a. _.��`�d`�` � � Il��,�. �qg ��P� 4 �� .� , �v � � � �Y � , ��g, ,��...z��i�� .y��'��''v,,3w�.. o,°" '�,�,yS' . � �! .� `e°_a � `�� a�i O�t?�< d'�c .D-. S?�,, w,ys ,� ��s ,p� . ga .i�f '3t � �^��h�A�yM1+a y�'� ��d � �n�y�i,p �6 6 . � '+m�1 �3� � f '+OP y'1� � yA�CT+� r �`r � 9' j q� " � a '�o � ` � � � �s� ,�`� �' . �z�'� ss� a ��,�� -��y � ��„� � �� ``� r�` .. FZ;��`. r��' .�,'��@ � ,��`,�r��ti:� ��"r��. �'�i. . ew'.�.,�m, asp' � +'� �.'�li� �(�"�. ^� �.'� < 'y. - Jy � N t: � . �s�Fg:,,'�(q. x�... _ . �`�aq, �LF .�0. �"�* "`��'� . � a��af �ti�� ' � � �+�'` �m�e�e�y ",� - � �� „ � o, . � � �� ;� � r F � 1 � � �� _ �i4 4,�_ 4h,�. � . �� ,"r �b �,, " ", y`' ,� � � � �� `'� �� '�� 3'0' ��►' �� j �a,�``�� , . ..P�; ' "��iw�� '.��',�. '�..� ��,`f^Pa � �e '°� �o� � �� S' � �. "� � U � f3�� y��'�" �� . r'� � ��,#"`�c. ;�T„�?,� � : ''Np^��,�,��y`� �� . . �s° �. : t.ssa i� . '�y�,� �, ' "�� r�'� �, ��'vk�� ,d��'�k �� t�, �� " � � ;- �a.,a��., g.��,,� g� ,��"��'p� � , ^ � o ',, T dE � �,�� ti,� � �� .: � 5 � . , ' ' _. _._ - �� asr��.� � i �{ � �9��e �!j";°F' �oe > . � � :��oHCa�iugs�s��.�`�,,�.� _� �r, � a�. �� t � ,m_ �-�.,� ' ... _ . , ,� , " � �� . _ �,f 2r� � 3� .,, �� 3N . ��,;, � "�� 4 a "4. , � �. � �_ ":"a3��yq2 .. . � iI� ,�+yt: � � �p,.e ��* y��rbc� �� *g �.33fi � � ��,w�' ��.. "P� ��,�' �+ S ' r � '�� . .. _ .. .,— . . .�� .»,.. ... �. �" . Y._ <_._. ��....�... :_-. . . _ . , .... , .. .� . �� V http://www.geodata.org/output/cadastral maps55516442839.png 8/29/2013 , Thurston Geodata Center- Parcel Search . Page 1 of 3 � �v'�� -1-�J�'a�i1MAT�O� �� W� �� f�� , ,E � . ��r.. Data for Parcel No. 21724410200 Zoom Map ta Parcel Google Earth (need to have Googie Earth installed on you system) Google Maps Virtua{ Earth Please make sure to REA.D our DA.TA DISCLAIMER 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��; S24171� 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 r°t 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 R�mero - 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% slopes 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 Dis#rict: SE THURSTON FIRE AND EMS Unconsolidated 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 20 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 2l http://www.geodata.org/website/cadastral/resultsparcel.asp?parce1=21724410200 8/29/2013 . , � ; S�"C�t�M tlt/A`i`E h T I��Al`Nt E�J T ��'I L�.1 T i C�N� Aqua-SwirlT'" Stormwat�r Treatment System Inspection �nd Maintenance Manual AquaShield,T"' Inc. 2705 Kanasita Drive, Chattanooga,TN 37343 Phone: (423)870-8888 Fax: (423) 826-2112 Email: info@aquashieldinc.com 2Z Table of Contents Introduction / Operation / Maintenance • Introduction to AquaShieldTM Stormwater Treatment Systems • Operation of the Aqua-SwirlT"^ Stormwater Treatment System I • Inspection & Maintenance of the Aqua-SwirITM System • Appendix Inspection & I�laintenance Data Sheet 2705 Kanasita Drive, Chattanooga, Tennessee 37343 Phone (888) 344-9044, Fax (423) 870-2112 www.aquashieldinc.com 2'i 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 AquaShieldTM 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 AquaShieldTM line of patented stormwater treatment products provide for high levels of stormwater treatment: • The Aqua-Swir/""Stormwater 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/ter""StormwaterFi/tration System is an treatment train stormwater �Itration 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. �"�' ��y, \\ $ \ . �: �� .� � �� .�;; � ;�� ,,��' ,� Y�� '\ �'�� .� �� ,, �. � - �`�.m.._ _�, Aqua-SwirlT"^ Stormwater Aqua-FilterT"' Stormwater Treatment System Filtration System 2'� . . A ua-SwirITM Stormwater Treatment A "�" System 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-Swirlr^'achieves a TSS removal of 91% calculated on a net annual basis. The Aqua-SwirlrM 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. � ,�s. �.�'� � . � ,� �.: �,�� ` ��s�'�� .. ;,��.��. ��: �� ,�.. � , . ._ ,. �`. � ..::. .. ;.; M.. � �� >^;� ' •,^`�� ,.. :, ' �� , ' � ; �. � � � �,��,.a� � . � , �� _ d � �; � �� , „3s.,'{.�f� ,�;'.IlL �E- . �., Lt�t C ,..I; ��Y, � � �� : � f ,� ��ri ��'��t � �, �° �, ,.. , i�..le.... �..:��u : �e�.. , ,. .b...,., .�s'.. �n,r'.�.: ..e..�,x�.i5 �.. ��..�kg . �. -- � �. �. ....; ..... ..... . ... .. . ZS . � "� Aqua-SwirITM �� ¢ Stormwater Treatment System The patented Aqua-SwirlT"' Stormwater Treatment System � ' �' provides a highly effective means for the removal of sediment, floating debris, and free oil. Swirl technology, �� °� �� r or vortex separation, is a proven � ,� ��' form of treatment utilized in the �'"` ��`�� " �� , . ��. �...� stormwater industry to accelerate y �� gravitational separation. `.��-:;� Independent university laboratory 6 �j�c performance evaluations have ''� � �t''';��"' shown the Aqua-SwirlT'" achieves a "�" TSS (Total Suspended Solids) removal of 91% calculated on a net �� " annual basis. See the "Performance ��.,` �s��'�� N <��;f��.�� ,�� and Testing"Section for more � details. Each Aqua-SwirITM 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. I �� -� 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. ti� 4 � The treatment operation begins � �� , , when stormwater enters the � ��` �`�� `�� , �� Aqua-Swirl�'" through a tangential inlet pipe that °� produces a circular (or vortex) � � , flow pattern that causes � contaminates to settle to the . �� ° � base of the unit. Since � v� � '�� stormwater flow is intermittent �' � � �� ;�,. �� a� �� by nature, the Aqua-Swir1T'" � ��' ' � �� retains water between storm � ��`�� ` � events providing both ��dynamic � � ,� �� `� � -: � � ��_ � , : , � � and quiescent settling of solids. ' I/ �� . F` v k� � xa ` �i�; „ � ... �� .. � �y " The dynamic settling occurs � ;��,�__ ,��"`�� during each storm event while Floatable debris in the Aqua-Swirl'"' 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 �� stormwater are �� ' �� reported to be small � p � � �� `�"`�"�`��`� �� and have low settling �� g � _�� velocities. Therefore, ~: the volume of water � �� i � � �� retained in the Aqua- �� y� � ` °`� Swir1T'" provides the � � ,�;� � � "�� quiescent settling that � `��;� � < �� :j � i increases performance. y�� ,� Furthermore, due to � ': finer sediment adhering � . �, ; onto larger particles �- � ' � � � .�� : (less than 200 microns), � � � the larger particles � �'; ��t �� settle, rather than � � �,; �' $ staying suspended in �� the water. ,,:; ti� e � The treated flow then exits the Aqua-SwirITM behind the arched outer baffle. 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-SwirlT"^ 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- SwirITM for treatment and conveyance back to the existing main conveyance storm drainage system. : f�� -.�- Custom Applications �...., ,K�w.,. . ,,,. ., „ .�. �_ . .. ...,�. The Aqua-SwirlT'" system can be �� modified to fit a variety of purposes - � � �j��,�� ' � in the field, and the angles for inlet ;,��y� � �� and outlet lines can be modified to ` � ` � ` fit most applications. The photo on � ' the left demonstrates the flexibility � � �� '�� of Aqua-Swir1T'" installations. Two ��, � " , � a,� ..�� r, � ;��, Aqua-SwirITM units were placed side : , . . } b side in order t o treat a hi h �, Y 9 � � a� �� =_��: t , � �� . �• :` volume of water while occupying a � � �� o � � � �� ,��; � small amount of space. This � �� confiQUration is an examqle of the ! � � ��t ti� �� _� . � �� \\�`�a\s`��v ��su�.. " Trvi j , �� '� many ways AquaShield can use � _ �� \ �\ � our products to adapt to a variety of ..... �„ .��; � Custom designed AS-9 Twin,Aqua-SwirITM applications. �ft,� �_y -��•-- Retrofit Applications The Aqua-SwirlT'" 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. Z� 1 . � I � °�..�..'.:'f: � `� AquaShieldTM Product � System Maintenance The long-term performance of the stormwater treatment ��,.� ,� ,., structures (including ��°��-� N �� =�v � : manufactured systems, �'� � ' .�- ponds, swales, etc.), and the `' .� �,e�, �`'�� effective protection of �, receiving waters, depends on �`��. �,� �� `� a consistent maintenance `� ��°� �� plan. Inspection and ��t � �► � � maintenance functions are � � e�� simple and easy for the _ _,,� ,� AquaShieldT'" Stormwater �k ° ' ,� ,.� Treatment Systems allowing `��; , �` � !� ��'�{�� w � all inspections to be � �� r� � � �� ` �� '«, � performed from the surface. �� 3 y w� rm,� �� iAn 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) tne nature of the area being drained. In order to ensure that �� our systems are being ,�� } ��N;�a� maintained properlY, �`�� .. � �� : AquaShield�"' offers a �� .. � F y� � , ��. _ � maintenance solution °~��. �� a'�� '��,,�, , ,_.�,,��_ ,�� ..�..��,.��,�>� �� to all of our customers. �� _ ;, y�� We will arrange to �� ` � � �� :.� .. � A �.�1 � i e�`' l�� . have maintenance ,� ��j�r � , �, � - ( perFormed. ��"'�""� �� ` �� y� a � � 4 a.� t�� *.�� .r j � �� ,` , °v . Z9 . , . 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. ��: .�- Aqua-SwirITM Maintenance 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-floati.ng oil and floatable dehris can be directly obserued and maintained through the manhole access provided directly over the swirl chamber. Aqua-SwirITM Inspection Procedure �� e�:�=�� To inspect the Aqua-Swir1T'", a hook is needed to remove � �� " �x the manhole cover. AquaShieldTM provides a customized ` h � manhole cover with our logo to make it easy for � �� s� °��- . maintenance crews to locate the system in the field. We � also provide a permanent metal information plate attached � �;, inside the access riser, which provides our contact � information, the Aqua-Swir1T'" model size, and serial �` �� number. �� 5 �� ... �:.�.. � ,. _„�,.�,,.. . ..,. �..,.��. , Sediment inspection using a stadia rod 3a i • • � � The only tools needed to inspect the Aqua- SwirlT'" 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. It should be noted that in order to avoid underestimating the volume of sediment in the chamber, the measuring device must be 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 ;,��. and floatable debris can be observed and removed directly through the 30-inch service access provided. �,�`` :� � � ` A vacuum, truck can be used to remov� thP accumul�tPd °' � �. _� sediment and debris. It is important to note that the entire sediment storage area can be reached with a vacuum u �� hose from the surface (reaching all the sides). �� - ° � �, Disposal of the material is typically treated in the same Vacuumtruckcleans^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► I ` ; � APPENDIX � ; ; � ; ; 3Z . , Aqua-SwirlT'" Inspection and Maintenance Manual for BMP Owners (Note: Atfach certifications for loc,al regulatory authority including any applicable fees.) Sife a►�d Ownerinformation' 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: lll�aintenance ltems Inspection Floatable Debris and Oil 1.Remove manhole lid to expose Iiquid surtace 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-SwirlT"'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 AccumulatiAn , 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): 4. Calculate distance to sediment minus distance to water(in): �°�� fF `- : � 5. Schedule cleaning if value in step 4 is 30"or less. (See Figure 3). '� a� � ��> ��'�°�� ti �3� � � � �� :.�� i 30" _ �� Figure 1 Figure 2 Aqua-SwirlT""1 and M Manual Page 1 33 � . � . Inspection{continued) ` ' F � : 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 should 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. Cleaning �� - : .� 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 ail materials removed during the maintenance process be handled and disposed of in accordance with local and state requirements. � ,� �,V, < �� " � � �;.�. �� ° , '� ..,,�..'"�� . . Figure 3 - NYaintenance 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-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 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 � ' � y Maintenance Company Information Company Name: Street Address: City,State,Zip: Contact: � � �� -: �' # � �`' ��i � j`' e Office Phone: ' � . � �_ �. ' .k--�,.,,,._ ��";: �`� ..�`�°� �°. Mobile Phone: ��, �. � �� Pager: �� 3"� ,�,�. Activity 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""I and M Manual Page 3 3'S � v i NOTES Additional Comments and/or Actions to Be Taken Time Frame NOTES: 1.Attach site plan showing Aqua-SwirlT"" 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 3�0 ,� .. � Aqua-SWIi'�TM 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 Inspecl and 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-Gonstruction Month Activity 1 2 3 4 5 6 7 8 9 10 11 12 Inspect and Clean as X X X X Needed Inspect Bypass SWctures � (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-Construction Month Activity 1 2 3 4 5 6 7 8 9 10 11 12 ---- - �_�� __.__.. Inspect en�s Ciean as Needed' X� InspectBypass 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""I and M Manuai Page 5 3'7