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2169_Drainange and Erosion Control Report El Rey_7-12-22El Rey Burro Yelm , WA Drainage & Erosion Control Report Fuller Designs Project No. 2169 February 18 , 2022 Prepared by: 1101 Kresky Ave, Centralia, WA 98531 360.807.4420 2 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG Project Information Prepared for: Martha Arriaga Hernandez Contact: 604 Yelm Ave W Yelm , WA 985 97 Reviewing Agency Jurisdiction: City of Yelm Contact: Derek McCoy, Civil Review Engineer (360) 458 -8132 References : 2019 Stormwater Management Manual for Western Washington Yelm Engineering Specifications and Standard Details City of Yelm Web Map USDA Web Soil Survey Project Engineer Prepared by: Fuller Designs, Inc. 1101 Kresky Ave Centralia, WA 98531 (360) 807 -4420 Contact: Aaron Fuller, PE "I hereby certify that this Drainage and Erosion Control Report for the El Rey Burro p roject has been prepared by me or under my supervision. I hereby acknowledge and agree that the jurisdiction does not and will not assume liability for the sufficiency, suitability, or performance of facilities designed by me." 3 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG Contents SECTION 1 – PROPOSED PROJECT DESCRIPTION ..................................................... 4 SECTION 2 – EXISTING CONDITIONS DESCRIPTION ................................................ 4 SECTION 3 – OFF -SITE ANALYSIS REPORTS ............................................................. 4 SECTION 4 – APPLICABLE MINIMUM REQUIREMENTS ............................................ 5 MR #1 – Preparation of Drainage Control Plans ................................................................................ 5 MR #2 – Construction Stormwater Pollution Prevention Plan ............................................................. 5 MR #4 – Preservation of Natural Drainage Systems and Outfalls ........................................................ 6 MR #5 – On-site Stormwater Management ........................................................................................ 6 MR #6 – Runoff Treatment .............................................................................................................. 6 MR #7 – Flow Control ..................................................................................................................... 7 MR #8 – Wetlands Protection .......................................................................................................... 7 MR #9 – Operation and Maintenance ................................................................................................ 7 SECTIO N 5 – PERMANENT STORMWATER CALCUALTIONS .................................... 8 Infiltration Facility ......................................................................................................................... 8 SECTION 6 – CONSTRUCTION SWPPP ........................................................................ 9 SECTION 7 – OPERATION AND MAINTENCE MANUAL .......................................... 17 SECTION 8 – SPECIAL REPORTS AND STUDIES ...................................................... 21 APPENDIX A .............................................................................................................. 22 4 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG Drainage & Erosion Control Report SECTION 1 – PROPOSED PROJECT DESCRIPTION Parcel Number(s): 21724141300 Site Address: 604 Yelm Ave W Yelm, WA 98597 Total Site Area: 0.30Acres Zoning: (C-1) Commercial Sec, Twn, Rge: Section 24, Township 17, Range 1E Proposed Improvements: Currently zoned as commercial, the 0.30-ac site , the El Rey Burro Project (Pro ject), entails development of the site as a drive -thru restaurant, including new building, paving of the site, and stormwater facilities. SECTION 2 – EXISTING CONDITIONS DESCRIPTION The Project , located at the corner of Yelm Ave and Longmire St., in Yelm , WA is primarily flat with a very slight northeastern slope. According to the City of Yelm Web Map tool, this site is located within a n extreme critical aquifer recharge area , however no other critical areas were identified. The USDA online tool, Web Soil Survey, depicts the site as covered completely by Spanaway gravelly sandy loams , confirmed by the geotechnical report by NW Quality Geo , Appendix A , that determined an infiltration rate of 8 -in/hr (page 10 of the geotechnical report). In its existing condition, the urban lot has a 15,000 -sf building, gravel and vegetation onsite. SECTION 3 – OFF -SITE ANALYSIS REPORTS The area immediately adjacent to the proposed project propert y is: • North Furniture retail, zoned COM • South SR 507 (Yelm Hwy SE) • East Parcel No. 217-724-141302, Zoned Land • West Parcel No. 217-24141206, Zoned Land The proposed improvements are not expected to cause adverse effects to the adjacent properties. The proposed plan maintains natural drainage paths, keeping all stormwater onsite and discharging to groundwater. Since imp acts are not anticipated further upstream and the area has not been flagged as a possible stormwater problem area, a further upstream analysis was determined unnecessary. A down stream analysis shows that any 5 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG water leaving the site would flow 150 -ft undeve loped land toward the northwest. Once water reaches a low area and cannot leave, it will infiltrate to the groundwater table. SECTION 4 – APPLICABLE MINIMUM REQUIREMENTS The minimum requirements for stormwater development and redevelopment sites are listed in Volume I Chapter three of the 2019 Washington State Department of Ecology Stormwater Management Manual for Western Washington (SWMMWW). Based on the thresholds given in Figures I - 3.2 (Figure 4.1, right), of the SWMMWW, the proposed project’s deve lopment triggers all minimum requirements, MRs, one through nine . M R #1 – Preparation of Drainage Control Plans A Stormwater Site Plan has been prepared (see Erosion Control and Drainage Plans). MR #2 – Construction Stormwater Pollution Prevention Plan A Construction Stormwater Pollution Prevention Plan (SWPPP) has been prepared (see Section 6 ). MR #3 – Source Control of Pollution All known, available, and reasonable source control BMPs shall be applied to the Project to limit pollutants from encountering stormwater. Project -specific construction BMPs will be provided dur ing construction , Section 6 . • S453: BMPs for Formation of Pollution Prevention Team • S454: BMPs for Preventive Maintenance/ Good Housekeeping • S455: BMPs for Spill Prevention and Cleanup • S457: BMPs for Inspections • S415: BMPs for Maintenance of Public & Private Utility Corridors and Facilities • S416: BMPs for Maintenance of Roadside Ditches • S417: BMPs for Maintenance of Stormwater Drainage & Treatment Systems • S407: BMPs for Dust Control at Disturbed Land Areas & Unpaved Roadways & Parking Lots • S411: BMPs for Landscaping & Lawn/ Vegetation Management Figure 4.1 – Flow chart from the SWMMWW showing applicable minimum requirements. 6 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG • S450: BMPs for Irrigation • S429: BMPs for Storage or Transfer (outside) of Solid Raw Materials, Byproducts, or Finished Products • S420: BMPs for Painting/ Finishing/ Coating of Vehicles/ Boats/ Buildings/ Equipment • S438: BMPs for Construction Demolition MR #4 – Preservation of Natural Drainage Systems and Outfalls Improvements onsite do not propose to impact natural drainages. Post -development proposes to infiltrate 100% of the stormwater runoff from the roof and proposed parking lot . Improvements onsite do not propose to impact natural drainages inside their associated buffers. MR #5 – On-site Stormwater Management This project is not inside of the UGA Limits and on a site smaller than five acres. Based on the thresholds given in Figure I -3.3 from the SWMMWW (Figure 4.2, right), BMPs from l ist s #1, #2 and #3 of Table I -3.2 in Volume I of the SWMMWW are not applicable as the LID performance st andards have been met and BMP T5.13, Post Construction Soil Quality and Depth, shall be implemented on the site . MR #6 – Runoff Treatment Prior to entering the infiltration facility, runoff produced from the site will undergo treatmen t via Contech Storm Catch Basins. Water quality flow rate was calculated (though WWHM Modeling) to be 0.0 2 6 4 -cfs, 11.85-gpm. This runoff is representative of just the volume that wil l pass through the Contech Catch Basin a s runoff produced by the roof will bypass treatment and is proposed to be directly plumbed into the infiltration facility. A single Contech Catch Basin can treat 12.53 -gpm. T herefore, a single treatment catch basin w ill accommodate the runoff produced by the impervious pollutant generating surfaces . A basin map and the WWHM report are contained in Appendix A . Figure 4.2 – Flow chart from the SWMMWW showing requirements for MR5 . 7 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG MR #7 – Flow Con trol BMP T7.20, Infiltration Trenches, shall be implemented to infiltrate 100% of runoff produced onsite. Trench calculations can be found in Section 5 of this document. MR #8 – Wetlands Protection So long as MR #5 and MR #6 are implemented correctly, no adverse impacts to wetland s are expected to occur. Additionally, we t lands were not identified in th e e xisting site condition analysis (Section 2 ). MR #9 – Operation and Maintenance All stormwater treatment and facility operation and maintenance inside the property b oundary shall be the obligation of the landowner. A detailed operation manual is in Section 7 of this report. 8 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG SECTION 5 – PERMANENT STORMWATER CALCUALTIONS Infiltration Facility To determine the size infiltration facility needed for this site , a 4 -ft deep trapezoidal pond with 0:1 (H:V) side slopes was modeled in WWHM2012. The total volume, V TOT , through the rise was found to be 1,873-cf. 𝑉𝑅𝑂𝑅=0.043 𝑎𝑐𝑐𝑠⁄∗43560 𝑐𝑠𝑎𝑐⁄=1,873c𝑐 The area, A Pipe , of eight 12-in (1-ft) pipe was calculated and found to be 6.28-sf. 𝐴𝑂�ℎ𝑛𝑐𝑟=8 [𝜋(𝐷𝑂�ℎ𝑛𝑐)2 4 ]=8 [𝜋(1𝑐𝑠)2 4 ]=6.28sf Next, the total area of the trench was found in a 4 -ft deep by 12.5-ft wide trench. This was modeled in WWHM with a 5 -ft deep pond and a riser of 4 -ft (since actual depth is riser depth). The total trench area was calculated to be 50-sf. 𝐴𝑅𝑟𝑐𝑛𝑐�𝑅𝑂𝑅=𝐷𝑐𝑝𝑠�∗𝑉�ℎ𝑐𝑠�=(4 ∗12.5)𝑐𝑠=50𝑠𝑐 The total area of void space (space between the rocks) was calculated by subtracting the area of the pipes from the total area of the trench and multiplying by the void space coefficient. Typically, this coefficient, X , is measured as 0.3 3 and 0.40 -percent. The total void space area was found to be 14.43 -sf. 𝐴𝑅𝑛𝑐𝑘 𝑉𝑛�ℎ𝑐𝑟=[(𝐴𝑅𝑟𝑐𝑛𝑐�−𝐴𝑂�ℎ𝑛𝑐𝑟)∗𝑉𝑉𝑛�ℎ𝑐 𝑅𝑛𝑎𝑐𝑐]=[(50 −6.28)𝑠𝑐∗0.33]=14.43𝑠𝑐 Next, the total area the stormwater expected to infiltrate was calculated. This was determined by the addition of the area in the pipes with the area in the void space and found to be 20.71 -sf. 𝐴𝑅𝑂𝑅=(𝐴𝑛�ℎ𝑛𝑐+𝐴𝑅𝑛𝑐𝑘 𝑉𝑛�ℎ𝑐𝑟)=(6.28 +14.43)𝑠𝑐=20.71s𝑐 Finally, the total length of the trench could be calculated by dividing the total runoff volume by the total area in the trench , this value was found to be 90-ft. 𝐿𝑅𝑟𝑐𝑛𝑐�= 𝑉𝑅𝑂𝑅 𝐴𝑅𝑂𝑅 =1873𝑐𝑐 20.71𝑠𝑐=90.4𝑐𝑠≅90𝑐𝑠 Based on these calculations it was determined to properly infiltrate, there needs to be a trench with eight , 1 -ft pipes at a length of 90-ft each . The plan proposes 9 0 ft long trench with a depth of 4ft and width of 12.5ft , and eight 12” pipe s connected via header and footer pipe s (each providing additional, unaccounted for storage). Based on these calculations and the WWHM model , the proposed facility will provid e sufficient infiltration area for the modeled stormwater . 9 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG SECTION 6 – CONSTRUC TION SWPPP This project is required to prepare a construction Storm Water Pollution Prevention Plan in accordance with MR #2 and must be prepared in accordance with Volume II Chapter 3 of the SWMMWW. This drainage and erosion control report is intended to supplement the construction SWPPP by utilizing other sections in this report to cover required narrative elements. Also, the construction and erosion control plans suppli ed for the project are to act as the required drawing component of the construction SWPPP. Intended BMPs which should be used during construction include, but are not limited to: • BMP C120: Temporary and Permanent Seeding • BMP C121: Mulching • BMP 130: Surface Roughening • BMP C140: Dust Control • BMP C153: Material Delivery, Storage and Containment • BMP C160: Certified Erosion and Sediment Control Lead • BMP C162: Scheduling • BMP C233: Silt Fence Elements unapplicable to the project are as follows: • Element 6, Protect Slopes • Element 8, Stabilize Channels and Outlets, • Element 10, Control Dewatering W hile erosion control measures must be taken, adverse effects from slopes are not expected as s teep slopes were not identified within the site . On -site channels are not present and therefore do not need to be stabilized. Additionally, dewatering activities are not expected to occur or proposed. 10 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG El Rey Burro Yelm, WA CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN (SWPPP) Fuller Designs Project No. 2169 February 18 , 2022 Prepared by: 1101 Kresky Ave, Centralia, WA 98531 360.807.4420 11 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG Stormwater Pollution Prevention Plan General Requirements Clearing and grading activities for the Project shall be permitted only to the approved site development plan. These clearing and grading areas were established to preserve sensitive areas, buffers, native growth protection easements, and tree retention ar eas. These areas are delineated on the site plans and shall be marked on the development site. The SWPPP shall be implemented beginning with initial land disturbance and until final stabilization. Sediment and Erosion Control BMPs shall be consistent wi th the BMPs contained in Chapters 3 and 4 of Volume II of the 2014 Washington State Department of Ecology (WSDOE) Stormwater Management Manual for Western Washington (SWMMWW). Seasonal Work Limitations - From October 15 through April 1, clearing, gradin g, and other soil disturbing activities shall only be permitted if shown to the satisfaction of the local permitting authority that silt -laden runoff will be prevented from leaving the site through a combination of the following: 1. Site conditions, including existing vegetative coverage, slope, soil type, and proximity to receiving waters 2. Limitations on activities and the extent of disturbed areas 3. Proposed erosion and sediment control measures Project Requirements - Construction SWPPP El ements In most cases, all the following elements shall apply and be implemented throughout project construction. Self -contained sites (discharges only to groundwater) must comply with all elements except for Element 3: Control Flow Rates. Element 1: Preserve Vegetation/Mark Clearing Limits • Before beginning land-disturbing activities, including clearing and grading, clearly mark all clearing limits, sensitive areas, and their buffers, and trees that are to be preserved within the construction area. • Retain the duff layer, native topsoil, and natural vegetation in an undisturbed state to the maximum degree practicable. Element 2: Establish Construction Access • Limit construction vehicle access and exit to one route, if possible. • Stabilize access points with a pad of quarry spalls, crushed rock, or other equivalent BMPs to minimize sediment tracking onto public roads. • Locate wheel wash or tire baths on-site if the stabilized construction entrance is not effective in preventing tracking sediment onto roads. 12 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG • If sediment is tracked off-site, clean the affected roadway thoroughly at the end of each day, or more frequently if necessary (for example, during wet weather). Remove the sediment from roads by shoveling, sweeping, or pick up and transport the sediment to a controlled sediment disposal area. • Conduct street washing only after the sediment is removed following the above procedure. • Control street wash wastewater by pumping back on-site or otherwise preventing it from discharging into systems tributary to the State's waters. Element 3: Control Flow Rates • Protect properties and waterways downstream of development sites from erosion and the associated discharge of turbid waters due to increases in the velocity and peak volumetric flow rate of stormwater runoff from the project site. • Where necessary to comply with the bullet above, construct stormwater retention or detention facilities as one of the first grading steps. Assure that detention facilities function properly before constructing site improvements (e.g., impervious surfaces). • If permanent infiltration ponds are used for flow control during construction, protect these facilities from siltation during the construction phase. Element 4: Install Sediment Controls • Design, install, and maintain adequate erosion controls, and sediment controls to minimize pollutants' discharge. • Construct sediment control BMPs (sediment ponds, traps, filters, etc.) as one of the first grading steps. These BMPs shall be functional before other land-disturbing activities take place. • Minimize sediment discharges from the site. The design, installation, and maintenance of erosion and sediment controls must address factors such as the amount, frequency, intensity and duration of precipitation, the nature of resulting stormwater runoff, and soil characteristics, including the range of soil particle sizes expected to be present on the site. • Before the runoff leaves a construction site or before the discharge to an infiltration facility, direct stormwater runoff from the disturbed areas through a sediment pond or other appropriate sediment removal BMP. Runoff from fully stabilized areas may be discharged without a sediment removal BMP but must meet the flow control performance standard in Element #3, bullet #1. • Locate BMPs intended to trap sediment on-site to avoid interference with juvenile salmonids' movement attempting to enter off-channel areas or drainages. • Where feasible, design outlet structures that withdraw impounded stormwater from the surface avoid discharging sediment that is still suspended lower in the water column. Element 5: Stabilize Soils • Stabilize exposed and unworked soils by application of effective BMPs that prevent erosion. Applicable BMPs include but are not limited to: temporary and permanent seeding, sodding, mulching, plastic covering, erosion control fabrics and matting, soil application of polyacrylamide (PAM), the early application of gravel base early on areas to be paved, and dust control. 13 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG • Control stormwater volume and velocity within the site to minimize soil erosion. • Control stormwater discharges, including peak flow rates and total stormwater volume, to minimize erosion at outlets and minimize downstream channel and stream bank erosion. • Soils must not remain exposed and unworked for more than the time periods set forth below to prevent erosion: o During the dry season (April 2 – October 14): 7 days o During the wet season (October 15 - April 1): 2 days o Note that projects performing work under an NPDES Construction Stormwater General Permit issued by Ecology will have more restrictive time periods. • Stabilize soils at the end of the shift before a holiday or weekend, if needed, based on the weather forecast. • Stabilize soil stockpiles from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. • Minimize the amount of soil exposed during construction activity. • Minimize the disturbance of steep slopes. • Minimize soil compaction and, unless infeasible, preserve topsoil. Element 6: Protect Slopes • Design and construct cut-and-fill slopes in a manner to minimize erosion. Applicable practices include, but are not limited to, reducing the continuous length of a slope with terracing and diversions, reducing slope steepness, and roughening sloped surfaces (for example, track walking). • Divert off-site stormwater (run-on) or groundwater away from slopes and disturbed areas with interceptor dikes, pipes, and/or swales. Off-site stormwater should be managed separately from stormwater generated on the site. • At the top of slopes, collect drainage in pipe slope drains or protected channels to prevent erosion. • Place excavated material on the uphill side of trenches, consistent with safety and space considerations. • Place check dams at regular intervals within constructed channels that are cut down a slope. Element 7: Protect Drain Inlets • Protect all storm drain inlets made operable during construction so that stormwater runoff shall not enter the conveyance system without first being filtered or treated to remove sediment. • Clean or remove and replace inlet protection devices when sediment has filled one-third of the available storage (unless the product manufacturer specifies a different standard). Element 8: Stabilize Channels and Outlets • Design, construct and stabilize all on-site conveyance channels. • Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches at the outlets of all conveyance systems. 14 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG Element 9: Control Pollutants • Design, install, implement, and maintain effective pollution prevention measures to minimize the discharge of pollutants. • Handle and dispose of all pollutants, including waste materials and demolition debris that occur on-site in a manner that does not contaminate stormwater. • Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum products, and other materials that have the potential to pose a threat to human health or the environment. On-site fueling tanks must include secondary containment. Secondary containment means placing tanks or containers within an impervious structure capable of containing 110% of the largest tank's volume within the containment structure. Double-walled tanks do not require additional secondary containment. • Conduct maintenance, fueling, and repair of heavy equipment and vehicles using spill prevention and control measures. Clean contaminated surfaces immediately following any spill incident. • To prevent discharge to surface water, discharge the wheel wash or tire bath wastewater to a separate on-site treatment system such as closed-loop recirculation or upland application, or the sanitary sewer, with local sewer district approval. • Apply fertilizers and pesticides in a manner and at application rates that will not result in a chemical loss to stormwater runoff. Follow manufacturers' label requirements for application rates and procedures. • Use BMPs to prevent contamination of stormwater runoff by pH modifying sources. The sources for this contamination include, but are not limited to: bulk cement, cement kiln dust, fly ash, new concrete washing and curing waters, waste streams generated from concrete grinding and sawing, exposed aggregate processes, dewatering concrete vaults, concrete pumping, and mixer washout waters. • Adjust the pH of stormwater if necessary, to prevent violations of water quality standards. • Assure that washout of concrete trucks is performed off-site or in designated concrete washout areas only. Do not wash out concrete trucks onto the ground or into storm drains, open ditches, streets, or streams. Do not dump excess concrete on-site, except in designated concrete washout areas. Concrete spillage or concrete discharge to surface waters of the State is prohibited. • Obtain written approval from Ecology before using a chemical treatment other than CO2 or dry ice to adjust pH. Element 10: Control De -Wateri ng • Discharge foundation, vault, and trench dewatering water, which has similar characteristics to stormwater runoff at the site, into a controlled conveyance system before discharge to a sediment trap or sediment pond. • Discharge clean, non-turbid dewatering water, such as well-point groundwater, to systems tributary to, or directly into surface waters of the State, as specified in Element #8, provided the dewatering flow does not cause erosion or flooding of receiving waters. Do not route clean dewatering water through stormwater sediment ponds. Note that "surface waters of the State" may exist on a construction site as well as off-site; for example, a creek running through a site. • Handle highly turbid or otherwise contaminated dewatering water separately from stormwater. 15 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG • Other treatment or disposal options may include: 1. Infiltration 2. Transport off-site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters 3. Ecology-approved on-site chemical treatment or other suitable treatment technologies 4. Sanitary or combined sewer discharge with local sewer district approval if there is no other option 5. Use of a sedimentation bag that discharges to a ditch or swale for small volumes of localized dewatering Element 11: Maintain BMPs • Maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to assure continued performance of their intended function following BMP specifications. • Remove all temporary erosion and sediment control BMPs within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. Element 12: Manage the Project • Phase development projects to the maximum degree practicable and consider seasonal work limitations. • Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Projects regulated under the Construction Stormwater General Permit must conduct site inspections and monitoring in accordance with Special Condition S4 of the Construction Stormwater General Permit. • Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP. • Projects that disturb one or more acres must have site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL). Project sites disturbing less than one acre may have a CESCL or a person without CESCL certification conduct inspections. By initiating construction, the SWPPP must identify the CESCL or inspector, who must always be present on- site or on-call. • The CESCL or inspector (project sites less than one acre) must have the skills to assess the: o Site conditions and construction activities that could impact the quality of stormwater o Effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges • The CESCL or inspector must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. They must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. • Based on the results of the inspection, construction site operators must correct the problems identified by: o Reviewing the SWPPP for compliance with the 13 construction SWPPP elements and making appropriate revisions within seven (7) calendar days of the inspection. 16 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG • Immediately begin the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems not later than within ten (10) days of the inspection. If the installation of necessary treatment BMPs is not feasible within ten (10) days, the construction site operator may request an extension within the initial 10day response period. • Documenting BMP implementation and maintenance in the site logbook (sites larger than one acre). • The CESCL or inspector must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.) The CESCL or inspector may reduce the inspection frequency for temporary stabilized, static sites to once every calendar month. Element 13: Protect Low Impact Development BMPs • Protect all Bioretention and Rain Garden BMPs from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the Bioretention and/or Rain Garden BMPs. Restore the BMPs to their fully functioning condition if they accumulate sediment during construction. Restoring the BMP must include removing sediment and any sediment-laden Bioretention/rain garden soils and replacing the removed soils with soils meeting the design specification. • Prevent compacting Bioretention and rain garden BMPs by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. • Control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements or base materials. • Pavement fouled with sediments or no longer passing an initial infiltration test must be cleaned using procedures in accordance with this manual or the manufacturer's procedures. • Keep all heavy equipment off existing soils under LID facilities excavated to final grade to retain the soils' infiltration rate. 17 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG SECTION 7 – OPERATION AND MAINTENCE MANUAL The following pages contains maintenance needs for the components that are part of the drainage system and components that you may not have. Let Fuller Designs know if any components 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 (preferably September) 3. After any major storm (use 1" of precipitation in 24 hours) for any items marked "S" Using photocopies of these pages, check off the items you looked for after each inspection. Add comments on issues found and actions taken. Keep these records in your files. These files will be needed to write your annual report if required. Some items may not need reviewed time an inspection is done. You may call the city for technical assistance. Please do not hesitate to reach out , especially if you are unsure whether a situation you have discovered may be a developing issue. 18 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG www.ContechES.com/stormwater | 800-338-1122 © 2020 Contech Engineered Solutions, a Quikrete Company Page 1 ENGINEERED SOLUTIONS OPERATION AND MAINTENANCE CatchBasin StormFilter™ Important: These guidelines should be used as a part of your site stormwater plan. Overview The CatchBasin StormFilter™ (CBSF) consists of a multi-chamber steel, concrete, or plastic catch basin unit. The steel CBSF is offered both as a standard and as a deep unit for additional internal overflow and sediment capacity. The CBSF is installed flush with the finished grade and is applicable for both constrained lot and retrofit applications. Steel and concrete units can accept surface and piped influent for roof leaders or similar applications. The steel, concrete and plastic CBSF units have capacities of 4, 8 and 2 cartridges, respectively. Internal overflow capacity varies by system type from 0.5 cfs for the plastic, 1.3 cfs for the concrete and 1.0 or 1.8 cfs for the steel unit. Design Operation The CBSF is installed as the primary receiver of runoff, similar to a standard, grated catch basin. The steel and concrete CBSF units have an H-20 rated, traffic bearing lid that allows the filter to be installed in parking lots, and for all practical purposes, takes up no land area. Plastic units can be used in landscaped areas or other non-traffic-bearing applications. The steel CBSF consists of a sumped inlet chamber and cartridge chamber(s). Runoff enters the sumped inlet chamber either by sheet flow from a paved surface or from an inlet pipe discharging directly to the unit vault. The inlet chamber is equipped with an internal baffle, which traps debris and floating oil and grease, and an overflow weir. While in the inlet chamber, heavier solids are allowed to settle into the deep sump, while lighter solids and soluble pollutants are directed into the cartridge chamber through a port between the baffle and the overflow weir. The concrete and plastic units operate similarly minus the presence of the inlet chamber or deep sump. Once in the cartridge chamber, polluted water ponds and percolates horizontally through the media in the filter cartridges. Treated water collects in the cartridge’s center tube from where it is directed to the outlet chamber and discharged to the outlet pipe on the downstream side of the overflow weir. When influent flows exceed the water quality design value, excess water spills over the overflow weir, bypassing the cartridge bay, and discharges to the outlet pipe. Applications The CBSF is particularly useful where small flows are being treated or for sites that have little available hydraulic head. The unit is ideal for applications in which standard catch basins are to be used. Both water quality and catchment issues can be resolved with the use of the CBSF. Retro-Fit The retrofit market has many possible applications for the CBSF. The CBSF can be installed by replacing an existing catch basin without having to “chase the grade,” thus reducing the high cost of re piping the storm system. 19 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG (A percolation test pit or test of facility indicates facility is only working at 90% of its designed capabilities. Test every 2 to 5 years. If two inches or more sediment is present, remove). Filter Bags (if applicable)Filled with Sediment and DebrisSediment and debris fill bag more than 1/2 full.Filter bag is replaced or system is redesigned.Rock FiltersSediment and DebrisBy visual inspection, little or no water flows through filter during heavy rain storms.Gravel in rock filter is replaced.Side Slopes of PondErosionSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsEmergency Overflow Spillway and Berms over 4 feet in height.Tree GrowthSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsPipingSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsEmergency Overflow SpillwayRock MissingSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsErosionSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsPre-settling Ponds and VaultsFacility or sump filled with Sediment and/or debris6" or designed sediment trap depth of sediment.Sediment is removed.Maintenance ComponentDefectConditions When Maintenance is NeededResults Expected When Maintenance is PerformedGeneralSediment AccumulationWhen sediment forms a cap over the insert media of the insert and/or unit.No sediment cap on the insert media and its unit.Trash and Debris AccumulationTrash and debris accumulates on insert unit creating a blockage/restriction.Trash and debris removed from insert unit. Runoff freely flows into catch basin.Media Insert Not Removing OilEffluent water from media insert has a visible sheen.Effluent water from media insert is free of oils and has no visible sheen.Media Insert Water SaturatedCatch basin insert is saturated with water and no longer has the capacity to absorb.Remove and replace media insertMedia Insert-Oil SaturatedMedia oil saturated due to petroleum spill that drains into catch basin.Remove and replace media insert.Media Insert Use Beyond Product LifeMedia has been used beyond the typical average life of media insert product.Remove and replace media at regular intervals, depending on insert product.Table V-A.18: Maintenance Standards - Catch Basin InsertsMaintenance ComponentDefectConditions When Maintenance Is NeededResults Expected When Maintenance Is Per-formedGeneralTrash & DebrisSee Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-tion Ponds Poisonous/Noxious VegetationSee Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-tion PondsContaminants and Pol-lutionSee Table V-A.1: Maintenance Standards - Detention PondsSee Table V-A.1: Maintenance Standards - Deten-tion PondsRodent HolesSee Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten-tion PondsStorage AreaSedimentWater ponding in infiltration pond after rainfall ceases and appropriate time allowed for infiltration. Treatment basins should infiltrate Water Quality Design Storm Volume within 48 hours, and empty within 24 hours after cessation of most rain events.Sediment is removed and/or facility is cleaned so that infiltration system works according to design.Table V-A.2: Maintenance Standards - Infiltration20 | P a g e 1101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG 21 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG S ECTION 8 – SPECIAL REPORTS AND STUDIES A WWHM2012 Model was ran to determine the amount runoff produced from the site and the water quality flow rate for treatment purposes. Mitigated and developed areas within the site basin are described in a Basin Map that aided the WWHM2012 Model ing . Both the WWHM report and Basin Map can be found in Appendix A . A geotechnical report was prepared by NW Quality Geo . 22 | P a g e 1 101 KRESKY AVE, CENTRALIA, WA 98531 T (360) 807 - 4420 U WWW.FULLERDESIGNS.ORG APPENDIX A Quality Geo NW, PLLC Serving All of Washington & Oregon | Geotechnical Investigations & Engineering Consultation Phone: 360-878-9705| Web: qualitygeonw.com | Mail: 420 Golf Club Rd SE, Ste 203, Lacey, WA 98503 10/7/2021 Fuller Designs Attn: Cassie Fuller 1101 Kresky Ave Centralia,WA Subject: Geotechnical Services Report Yelm Drive-Thru - Geotechnical Investigation 604 W. Yelm Avenue, Yelm WA Project Number: QG21-114 Dear Ms. Fuller: At your request, Quality Geo NW, PLLC (QG) has completed a soils investigation of the above referenced project. The investigation was performed in accordance with our proposal for professional services. We would be pleased to continue our role as your geotechnical consultant of record during the project planning and construction phases, as local inspection firms have not been found to be as familiar or reliably experienced with geotechnical design. This may include soil subgrade inspections, periodic review of special inspection reports, or supplemental recommendations if changes occur during construction. We will happily meet with you at your convenience to discuss these and other additional Time & Materials services. We thank you for the opportunity to be of service on this project and trust this report satisfies your project needs currently. QG wishes you the best while completing the project. Respectfully Submitted, Quality Geo NW, PLLC Luke Preston McCann, L.E.G. Ray Gean II Principal Licensed Engineering Geologist Staff Geologist Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 2 SOILS REPORT YELM DRIVE-THRU 604 W. YELM AVENUE YELM, WA Fuller Designs Attn: Cassie Fuller 1101 Kresky Ave Centralia, WA Prepared by: Ray Gean Luke Preston McCann, L.E.G. Staff Geologist Principal Licensed Engineering Geologist Quality Geo NW, PLLC Geotechnical Investigation & Engineering Consultation Phone: 360-878-9750| Web: qualitygeonw.com Mail: 420 Golf Club Rd SE, Ste 203, Lacey, WA 98503 10/7/2021 QG Project # QG21-114 Copyright © 2021 Quality Geo NW, PLLC All Rights Reserved 10/7/2021 Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 3 TABLE OF CONTENTS 1.0 INTRODUCTION ...............................................................................................................4 1.1 PROJECT DESCRIPTION ............................................................................................................................. 4 1.2 FIELD WORK ................................................................................................................................................ 4 2.0 EXISTING SITE CONDITIONS ........................................................................................5 2.1 AREA GEOLOGY .......................................................................................................................................... 5 2.2 SITE & SURFACE CONDITIONS ................................................................................................................ 5 2.3 SOIL LOG ....................................................................................................................................................... 5 2.4 SURFACE WATER AND GROUNDWATER CONDITIONS ..................................................................... 6 3.0 GEOTECHNICAL RECOMMENDATIONS .....................................................................7 3.1 SHALLOW FOUNDATION RECOMMENDATIONS ................................................................................. 7 3.1.1 BUILDING SLAB ON GRADE FLOOR ............................................................................................. 8 3.2 INFILTRATION RATE DETERMINATION ................................................................................................ 9 3.2.1 GRADATION ANALYSIS METHODS & RESULTS ......................................................................... 9 3.2.2 TREATMENT POTENTIAL .............................................................................................................. 11 3.2.3 DRAINAGE RECOMMENDATIONS ............................................................................................... 11 3.3 IMPERVIOUS PAVEMENT CONSIDERATIONS .................................................................................... 11 4.0 CONSTRUCTION RECOMMENDATIONS ...................................................................13 4.1 EARTHWORK ............................................................................................................................................. 13 4.1.1 GRADING & EXCAVATION ............................................................................................................ 13 4.1.2 SUBGRADE EVALUATION & PREPARATION ............................................................................ 13 4.1.3 SITE PREPARATION, EROSION CONTROLL, WET WEATHER............................................... 13 4.2 STRUCTURAL FILL MATERIALS AND COMPACTION ....................................................................... 14 4.2.1 MATERIALS ...................................................................................................................................... 14 4.2.2 FILL PLACEMENT AND COMPACTION ...................................................................................... 15 4.3 TEMPORARY EXCAVATIONS AND SLOPES ........................................................................................ 15 5.0 SPECIAL INSPECTION ...................................................................................................17 6.0 LIMITATIONS ..................................................................................................................18 Region & Vicinity Maps ................................................................................................................ 19 Exploration Map ............................................................................................................................. 20 Exploration Logs ............................................................................................................................ 21 Laboratory Results ......................................................................................................................... 25 Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 4 1.0 INTRODUCTION This report presents the findings and recommendations of Quality Geo NW’s (QG) soil investigation conducted in support of new site surface improvements. 1.1 PROJECT DESCRIPTION QG understands the project entails development of the site as a drive-thru restaurant, including new building and paving of the site. Exterior improvements are anticipated to include infrastructure for auto access and parking, flatworks, and other necessary site amenities. QG has been contracted to perform a soils investigation of the proposed site to provide stormwater and earthwork recommendations. 1.2 FIELD WORK Site exploration activities were performed on 9/10/2021. Exploration locations were marked in the field by an QG Project Geologist with respect to the provided map and cleared for public conductible utilities. Our exploration locations were selected by an QG Project Geologist prior to field work to provide safest access to relevant soil conditions. The geologist directed the advancement of 3 excavated test pits (TP). The test pits were advanced within the vicinity of the anticipated development footprint areas, to depths of 10.0 feet below present grade (BPG) in general accordance with the specified contract depth. During explorations QG logged each soil horizon we encountered, and field classified them in accordance with the Unified Soil Classification System (USCS). Representative soil samples were collected from each unit, identified according to boring location and depth, placed in plastic bags to protect against moisture loss, and were transported to the soil laboratory for supplemental classification and other tests. QG advanced 1 Wildcat Dynamic Cone Penetrometer (DCP) tests at a representative location within the vicinity of a proposed structure location and as conditions permitted. The penetrometer test was terminated upon reaching the equipment’s maximum practical extent. During penetrometer advancement, blow counts were recorded in 10-centimeter increments as a thirty- five-pound weight was dropped a distance of 15 inches. Blow counts were then converted to resistance (kg/cm2), standard penetration blow counts (N-values), and corresponding soil consistency, with complete results shown on the attached logs. An aerial site plan with relevant features is presented in Appendix A. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 5 2.0 EXISTING SITE CONDITIONS 2.1 AREA GEOLOGY QG reviewed available map publications to assess known geologic conditions and hazards present at the site location. The Washington Geologic Information Portal (WGIP), maintained by the Department of Natural Resources Division of Geology and Earth Resources, provides 1:100,000- scale geologic mapping of the region. Geology of the site location and vicinity consists of continental glacial outwash, gravel deposits (Qgog). The outwash on site is described as being typically Recessional and proglacial, stratified pebble, cobble, and boulder gravel deposited in meltwater streams and their deltas; locally contains ice-contact deposits. The WGIP Map also offers layers of mapped geohazard conditions within the state. According to the regional-scale interactive map, no known geohazards are mapped for the site. The United States Department of Agriculture portal (USDA), provides a soil mapping of the region. The soils in the vicinity are mapped as Spanaway Gravelly Sandy Loam (110), these are derived from terraces, outwash plains and are formed by volcanic ash over gravelly outwash. The soils are described as gravelly sandy loam from 0 to 15 inches, very gravelly loam from 15 to 20 inches, and extremely gravelly sand from 20 to 60 inches. Depth to restrictive feature is more than 80 inches. Capacity of most limiting layer to transmit water (ksat), is listed as high low (1.98 to 5.95 in/hr). Depth to water more than 80 inches. 2.2 SITE & SURFACE CONDITIONS The project area is relatively flat, near the same elevation as the adjacent road, The site is currently developed, with one structure, and concrete within the parcel, and mostly grasses, low-lying shrub covering small portions of the site. 2.3 SOIL LOG Site soil conditions were generally identical across the property in all 3 test pits. Representative lab samples were taken from TP-1. Soil conditions on site were as follows: • 0.0’ to 2.0’ – Topsoil: An overriding 24-inch layer of topsoil was present over most of the site. • 2.0’ to 10.0’ – Well Graded Sand with Gravel (SW) Beneath topsoil, native sediments resemble a tan sandy gravelly glacial outwash, with minimal fines content and high cobble content, in a typically medium dense condition. Soils within the other test pit locations of the site were the same as TP-1 No groundwater Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 6 was encountered within this unit or any test pits down to maximum depth of 10 feet below present grade. 2.4 SURFACE WATER AND GROUNDWATER CONDITIONS No active surface water features are present on site. During our test pit explorations, no pervasive groundwater table was encountered. This groundwater table is inferred to exist at approximately 58 feet beneath the entire site, based on well logs made publically available by the WA Department of Ecology. Due to the time of year, it may be assumed that the explorations did not occur during the seasonal high, and the water table may raise during the mid-winter months. QG’s scope of work did not include determination or monitoring of seasonal groundwater elevation variations, formal documentation of wet season site conditions, or conclusive measurement of groundwater elevations at depths past the extent feasible for explorations at the time of the field explorations. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 7 3.0 GEOTECHNICAL RECOMMENDATIONS 3.1 SHALLOW FOUNDATION RECOMMENDATIONS QG recommends excavating loose or organic cover soils down to firm bearing conditions expected within 0.5 feet from the surface. QG recommends that foundations be placed on compacted native soils, or on firm structural fill installed over these compacted soils to achieve footing grade. Assuming site preparation is completed as described above, we recommend the following: • Subgrade Preparation QG recommends excavating and clearing any loose or organic cover soils, including the thin overriding layer of topsoil where necessary, from areas of proposed building and pavement construction, down to firm bearing conditions and benching the final bottom of subgrade elevation flat. Excavations should be performed with a smooth blade bucket to limit disturbance of subgrade soils. Vibratory compaction methods are suitable for densification of the non-organic native soils. After excavations have been completed to the planned subgrade elevations, but before placing fill or structural elements, the exposed subgrade should be evaluated under the periodic guidance of a QG representative. Any areas that are identified as being soft or yielding during subgrade evaluation should be brought to the attention of the geotechnical engineer. Where over excavation is performed below a structure, the over excavation area should extend beyond the outside of the footing a distance equal to the depth of the over excavation below the footing. The over excavated areas should be backfilled with properly compacted structural fill. For continuous footing elements, upon reaching bearing strata, we recommend benching foundation lines flat. Continuous perimeter and strip foundations may be stepped as needed to accommodate variations in final subgrade level. We also recommend maximum steps of 18 inches with spacing of at least 5 feet be constructed unless specified otherwise by the design engineer. Structural fill may then be placed as needed to reestablish final foundation grade. • Allowable Bearing Capacity: Up to 1,500 pounds per square foot (psf) for foundations placed on compacted native soil or on approved structural fill soils placed in accordance with the recommendations of Section 4.2. Bearing capacities, at or below 1,500 psf may eliminate the need for additional inspection requirements if approved by the county. The allowable bearing capacity may be increased by 1/3 for transient loading due to wind and seismic events. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 8 • Minimum Footing Depth: For a shallow perimeter and spread footing system, all exterior footings shall be embedded a minimum of 18 inches and all interior footings shall be embedded a minimum of 12 inches below the lowest adjacent finished grade, but not less than the depth required by design. However, all footings must also penetrate to the prescribed bearing stratum cited above. Minimum depths are referenced per IBC requirements for frost protection; other design concerns may dictate greater values be applied. • Minimum Footing Width: Footings should be proportioned to meet the stated bearing capacity and/or the IBC 2012 (or current) minimum requirements. For a shallow perimeter and spread footing system, continuous strip footings should be a minimum of 16 inches wide and interior or isolated column footings should be a minimum of 24 inches wide. • Estimated Settlements: All concrete settles after placement. We estimate that the maximum settlements will be on the order of 0.5 inch, or less, with a differential settlement of ½ inch, or less, over 50 linear feet. Settlement is anticipated to occur soon after the load is applied during construction. 3.1.1 BUILDING SLAB ON GRADE FLOOR QG anticipates that slab-on-grade floors are planned for the interior of the proposed building. Based on typical construction practices, we assume finished slab grade will be similar to or marginally above present grade for the below recommendations. If floor grades are planned to be substantially raised or lowered from existing grade, QG should be contacted to provide revised or alternative recommendations. • Capillary Break: A capillary break will be helpful to maintain a dry slab floor and reduce the potential for floor damage resulting from shallow perched water inundation. To provide a capillary moisture break, a 6-inch thick, properly compacted granular mat consisting of open-graded, free- draining angular aggregate is recommended below floor slabs. To provide additional slab structural support, or to substitute for a structural fill base pad where specified, QG recommends the capillary break should consist of crushed rock all passing the 1-inch sieve and no more than 3 percent (by weight) passing the U.S. No. #4 sieve, compacted in accordance with Section 5.2.2 of this report. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 9 • Vapor Barrier: A vapor retarding membrane such as 10 mil polyethylene film should be placed beneath all floor slabs to prevent transmission of moisture where floor coverings may be affected. Care should be taken during construction not to puncture or damage the membrane. To protect the membrane, a layer of sand no more than 2 inches thick may be placed over the membrane if desired. If excessive relict organic fill material is discovered at any location, additional sealant or more industrial gas barriers may be required to prevent off-gassing of decaying material from infiltrating the new structure. These measures shall be determined by the structural engineer to meet local code requirements as necessary. • Structural Design Considerations: QG assumes design and specifications of slabs will be assessed by the project design engineer. We suggest a minimum unreinforced concrete structural section of 4.0 inches be considered to help protect against cracking and localized settlement, especially where larger equipment or localized loads are anticipated. It is generally recommended that any floor slabs and annular exterior concrete paving subject to vehicular loading be designed to incorporate reinforcing. Additionally, some level of reinforcing, such as a wire mesh may be desirable to prolong slab life due to the overwhelming presence of such poor underlying soils. It should be noted that QG does not express any guarantee or warranty for proposed slab sections. 3.2 INFILTRATION RATE DETERMINATION QG understands design of on-site stormwater controls are pending the results of this study to confirm design parameters and interpreted depths to perched seasonal groundwater and restrictive soil features. 3.2.1 GRADATION ANALYSIS METHODS & RESULTS During test pit excavations for general site investigation, QG additionally collected representative samples of native soil deposits among potential infiltration strata and depths. Representative soil samples were selected from the northwest corner of the site (where an infiltration pond is proposed) to characterize the local infiltration conditions. We understand the project will be subject to infiltration design based on the Washington Department of Ecology Stormwater Management Manual for Western Washington (DoE SMMWW). For initial site infiltration characterization within the scope of this study, laboratory gradation analyses were completed including sieve and hydrometer tests for stormwater design characterization and rate determination to supplement field observations. Results of laboratory testing in terms of rate calculation are summarized below. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 10 Laboratory results were interpreted to recommended design inputs in accordance with methods of the 2019 DoE SMMWW. Gradation results were applied to the Massmann (2003) equation (1) to calculate Ksat representing the initial saturated hydraulic conductivity. (1) log10(Ksat) = -1.57 + 1.90*D10 + 0.015*D60 - 0.013*D90 - 2.08*ff Corrected Ksat values presented below are a product of the initial Ksat and correction factor CFT. For a generalized site-wide design situation, we have applied a site variability factor of CFv = 0.7 along with typical values of CFt = 0.4 (for the Grain Size Method) and CFm = 0.9 (assuming standard influent control). (2) CFT = CFv x CFt x CFm = 0.7 x 0.4 x 0.9 = 0.25 Results were cross-referenced with test pit logs to determine the validity and suitability of unique materials as an infiltration receptor. Additional reduction factors were applied for practical rate determination based on our professional judgement. Table 1. Results Of Massmann Analysis TP # Sample Depth (BPG) Unit Extent (ft) Soil Type D10 D60 D90 Fines (%) Ksat (in/hr) Correct ed Ksat (in/hr) LT Design Infiltration Rate(in/hr) Cation Exchange Capacity (meq/100g) Organic Content % 1 9.0 2 to 10 GW 0.23 14.0 40 0.9 33.21 8.30 8.30 9.3 0.6 3 3.0 2.5 to 10+ SW 0.14 1.8 19 5.6 32.43 8.10 8.10 15.0 4.9 Beneath topsoils, the lower brown to tan outwash soils were observed to generally exhibit minimal fines content and minimal oxidation patterns. In-ground infiltration structures are required to maintain a minimum separation from restrictive soil & groundwater features. For in-ground infiltration galleries, we recommend a maximum design rate of up to 8.0 inch/hour be considered. For any shallow infiltration features such as rain gardens, pervious pavement or swales, we recommend the designer consider a reduced rate of 8.0 inches per hour which is typically suitable for most shallow infiltration features, and considers potential reductions from compaction during construction. QG recommends the facility designer review these results and stated assumptions per reference literature to ensure applicability with the proposed development, level of anticipated controls, and long- term maintenance plan. The designer may make reasonable adjustments to correction factors and the resulting design values based on these criteria to ensure design and operational intent is met. We recommend that we be contacted if substantial changes to rate determination are considered. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 11 3.2.2 TREATMENT POTENTIAL Depending on stormwater and runoff sources, some stormwater features, such as rain gardens or pervious pavements may require treatment. Stormwater facilities utilizing native soils as treatment media typically require Cation Exchange Capacities (CEC) of greater than 5 milliequivalents per 100grams (meq/100g) and organic contents greater than 1% (this may vary depending on local code). The underlying tan gravels in TP-1 did not meet these treatment standards. However, the underlying tan sands in TP-3 did meet these treatment standards. 3.2.3 DRAINAGE RECOMMENDATIONS QG recommends proper drainage controls for stormwater runoff during and after site development to protect the site. The ground surface adjacent to structures should be sloped to drain away at a 5% minimum to prevent ponding of water adjacent to them. QG recommends all stormwater catchments (new or existing) be tightlined (piped) away from structures to an existing catch basin, stormwater system, established channel, or approved outfall to be released using appropriate energy-dissipating features at the outfall to minimize point erosion. Roof and footing drains should be tightlined separately or should be gathered in an appropriately sized catch basin structure and redistributed collectively. If storm drains are incorporated for impervious flatworks (driveways, sidewalks, etc.) collected waters should also be discharged according to the above recommendations. Based on our observations of a shallow groundwater table, appropriate measures should be taken by the site designer to consider and allow for an adequate emergency outfall location in the event of future record stormwater fall that cannot be anticipated. 3.3 IMPERVIOUS PAVEMENT CONSIDERATIONS QG anticipates most pavements will be constructed of flexible Hot Mix Asphalt surfacing, with thickened sections for anticipated heavy load areas. The main entrance/exit drive will likely experience different traffic volumes than the far end of the pavement areas. As a result, consideration could be given to increasing the pavement section in the main entrance/exit drive. Pavement sections presented in the above table should not be used for areas which experience repeated truck traffic/parking, equipment or truck parking areas, entrances and exit aprons, or contain trash dumpster loading zones. In these areas, a Portland Cement Concrete (PCC) pavement should be used, as opposed to HMA. One of the important considerations in designing a high quality and durable pavement is providing adequate drainage. Design of drainage for the proposed pavement section is outside of QG ’s scope of work at this time. It is important that bird baths (leeching basins) and surface waves are not created during construction of the HMA layer. A proper slope should also be allowed, and drainage Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 12 should be provided along the edges of pavements and around catch basins to prevent accumulation of free water within the base course, which otherwise may result in subgrade softening and pavement deterioration under exposure and repeated traffic conditions. All pavements require regular maintenance and repair in order to maintain the serviceability of the pavement. These repairs and maintenance are due to normal wear and tear of the pavement surface and are required in order to extend the serviceability life of the pavement. However, after 10 years of service, a normal pavement structure is likely to deteriorate to a point where pavement rehabilitation may be required to maintain the serviceability. The deterioration is more likely if the pavement is constructed over poor subgrade soils or in area of higher traffic volumes. Rigid pavement components are commonly utilized for portions of accesses and ancillary exterior improvements. The project civil designer may re-evaluate the below general recommendations for pavement thicknesses and base sections, if necessary, to ensure proper application to a given structure and use. QG recommends that we be contacted for further consultation if the below sections are proposed to be reduced. Concrete driveway aprons and curb alignments, if utilized, should consist of a minimum 6-inch thickness of unreinforced concrete pavement over structural base fill. Base thickness should correspond to related location and anticipated traffic loading. For light traffic areas, a 6-inch minimum base thickness (total 12-inch section) can be applied. For heavy traffic zones, we recommend allotting a 12- inch minimum base section beneath the pavement, or the incorporation of reinforcing steel in the concrete. Concrete sidewalks, walkways and patios if present may consist of a minimum 4-inch section of plain concrete (unreinforced) installed over a 6-inch minimum compacted base of crushed rock. At locations where grade has been raised with structural fill, a 4-inch minimum crushed rock section may be used. Flatworks should employ frequent joint controls to limit cracking potential. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 13 4.0 CONSTRUCTION RECOMMENDATIONS 4.1 EARTHWORK 4.1.1 GRADING & EXCAVATION A grading plan was not available to QG at the time of this report. However, based on provided conceptual plans, this study assumes finished site grade will approximate current grade. Therefore, depths referred to in this report are considered roughly equivalent to final depths. Excavations can generally be performed with conventional earthmoving equipment such as bulldozers, scrapers, and excavators. 4.1.2 SUBGRADE EVALUATION & PREPARATION After excavations have been completed to the planned subgrade elevations, but before placing fill or structural elements, the exposed subgrade should be evaluated under the part-time observation and guidance of an QG representative. The special inspection firm should continuously evaluate all backfilling. Any areas that are identified as being soft or yielding during subgrade evaluation should be over excavated to a firm and unyielding condition or to the depth determined by the geotechnical engineer. Where over excavation is performed below a structure, the over excavation area should extend beyond the outside of the footing a distance equal to the depth of the over excavation below the footing. The over excavated areas should be backfilled with properly compacted structural fill. 4.1.3 SITE PREPARATION, EROSION CONTROLL, WET WEATHER Any silty or organic rich native soils may be moisture-sensitive and become soft and difficult to traverse with construction equipment when wet. During wet weather, the contractor should take measures to protect any exposed soil subgrades, limit construction traffic during earthwork activities, and limit machine use only to areas undergoing active preparation. Once the geotechnical engineer has approved subgrade, further measures should be implemented to prevent degradation or disturbance of the subgrade. These measures could include, but are not limited to, placing a layer of crushed rock or lean concrete on the exposed subgrade, or covering the exposed subgrade with a plastic tarp and keeping construction traffic off the subgrade. Once subgrade has been approved, any disturbance because the subgrade was not protected should be repaired by the contractor at no cost to the owner. During wet weather, earthen berms or other methods should be used to prevent runoff from draining into excavations. All runoff should be collected and disposed of properly. Measures may Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 14 also be required to reduce the moisture content of on-site soils in the event of wet weather. These measures can include, but are not limited to, air drying and soil amendment, etc. QG recommends earthwork activities take place during the summer dry season. 4.2 STRUCTURAL FILL MATERIALS AND COMPACTION 4.2.1 MATERIALS All material placed below structures or pavement areas should be considered structural fill. Excavated native soils may be considered suitable for reuse as structural fill on a case-by-case basis. Imported material can also be used as structural fill. Care should be taken by the earthwork contractor during grading to avoid contaminating stockpiled soils that are planned for reuse as structural fill with native organic materials. Frozen soil is not suitable for use as structural fill. Fill material may not be placed on frozen soil. Structural fill material shall be free of deleterious materials, have a maximum particle size of 4 inches, and be compactable to the required compaction level. Imported structural fill material should conform to the WSDOT manual Section 9-03.14(1) Gravel Borrow, or an approved alternative import material. Controlled-density fill (CDF) or lean mix concrete can be used as an alternative to structural fill materials, except in areas where free-draining materials are required or specified. Imported materials utilized for trench back fill shall conform to Section 9-03.19, Trench Backfill, of the most recent edition (at the time of construction) of the State of Washington Department of Transportation Standard Specifications for Road, Bridge, and Municipal Construction (WSDOT Standard Specifications). Imported materials utilize as grade fill beneath roads shall conform to WSDOT Section 9-03.10, Gravel Base. Pipe bedding material should conform to the manufacturer’s recommendations and be worked around the pipe to provide uniform support. Cobbles exposed in the bottom of utility excavations should be covered with pipe bedding or removed to avoid inducing concentrated stresses on the pipe. Soils with fines content near or greater than 10% fines content may likely be moisture sensitive and become difficult to use during wet weather. Care should be taken by the earthwork contractor during grading to avoid contaminating stockpiled soils that are planned for reuse as structural fill with native organic materials. The contractor should submit samples of each of the required earthwork materials to the materials testing lab for evaluation and approval prior to delivery to the site. The samples should be Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 15 submitted at least 5 days prior to their delivery and sufficiently in advance of the work to allow the contractor to identify alternative sources if the material proves unsatisfactory. 4.2.2 FILL PLACEMENT AND COMPACTION For lateral and bearing support, structural fill placement below footings shall extend at minimum a distance past each edge of the base of the footing equal to the depth of structural fill placed below the footing [i.e. extending at least a 1H:1V past both the interior and the exterior of the concrete footing]. Prior to placement and compaction, structural fill should be moisture conditioned to within 3 percent of its optimum moisture content. Loose lifts of structural fill shall not exceed 12 inches in thickness. All structural fill shall be compacted to a firm and unyielding condition and to a minimum percent compaction based on its modified Proctor maximum dry density as determined per ASTM D1557. Structural fill placed beneath each of the following shall be compacted to the indicated percent compaction: • Foundation and Floor Slab Subgrades: 95 Percent • Pavement Subgrades & wall backfill (upper 2 feet): 95 Percent • Pavement Subgrades & wall backfill (below 2 feet): 90 Percent • Utility Trenches (upper 4 feet): 95 Percent • Utility Trenches (below 4 feet): 90 Percent A sufficient number of tests should be performed to verify compaction of each lift. The number of tests required will vary depending on the fill material, its moisture condition and the equipment being used. Initially, more frequent tests will be required while the contractor establishes the means and methods required to achieve proper compaction. Jetting or flooding is not a substitute for mechanical compaction and should not be allowed. 4.3 TEMPORARY EXCAVATIONS AND SLOPES All excavations and slopes must comply with applicable local, state, and federal safety regulations. Construction site safety is the sole responsibility of the Contractor, who shall also be solely responsible for the means, methods, and sequencing of construction operations. We are providing soil type information solely as a service to our client for planning purposes. Under no circumstances should the information be interpreted to mean that QG is assuming responsibility for construction site safety or the Contractor’s activities; such responsibility is not being implied and should not be inferred. The contractor shall be responsible for the safety of personnel working in utility trenches. Given that steep excavations in native soils may be prone to caving, we recommend all utility trenches, but particularly those greater than 4 feet in depth, be supported in Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 16 accordance with state and federal safety regulations. Heavy construction equipment, building materials, excavated soil, and vehicular traffic should not be allowed near the top of any excavation. Temporary excavations and slopes should be protected from the elements by covering with plastic sheeting or some other similar impermeable material. Sheeting sections should overlap by at least 12 inches and be tightly secured with sandbags, tires, staking, or other means to prevent wind from exposing the soils under the sheeting. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 17 5.0 SPECIAL INSPECTION The recommendations made in this report assume that an adequate program of tests and observations will be made throughout construction to verify compliance with these recommendations. Testing and observations performed during construction should include, but not necessarily be limited to, the following: • Geotechnical plan review and engineering consultation as needed prior to construction phase, • Observations and testing during site preparation, earthwork, structural fill, and pavement section placement, • Consultation on temporary excavation cutslopes and shoring if needed, • Consultation as necessary during construction. QG recommends that a local and reputable materials testing & inspection firm be retained for construction phase testing and observation in accordance with the local code requirements. We also strongly recommend that QG be retained as the project Geotechnical Engineering Firm of Record (GER) during the construction of this project to perform periodic supplementary geotechnical observations and review the special inspectors reports during construction. Our knowledge of the project site and the design recommendations contained herein will be of great benefit in the event that difficulties arise and either modifications or additional geotechnical engineering recommendations are required or desired. We can also, in a timely fashion observe the actual soil conditions encountered during construction, evaluate the applicability of the recommendations presented in this report to the soil conditions encountered, and recommend appropriate changes in design or construction procedures if conditions differ from those described herein. We would be pleased to meet with you at your convenience to discuss the Time & Materials scope and cost for these services. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 18 6.0 LIMITATIONS Upon acceptance and use of this report, and its interpretations and recommendations, the user shall agree to indemnify and hold harmless QG, including its owners, employees and subcontractors, from any adverse effects resulting from development and occupation of the subject site. Ultimately, it is the owner’s choice to develop and live in such an area of possible geohazards (which exist in perpetuity across the earth in one form or another), and therefore the future consequences, both anticipated and unknown, are solely the responsibility of the owner. By using this report for development of the subject property, the owner must accept and understand that it is not possible to fully anticipate all inherent risks of development. The recommendations provided above are intended to reduce (but may not eliminate) such risks. This report does not represent a construction specification or engineered plan and shall not be used or referenced as such. The information included in this report should be considered supplemental to the requirements contained in the project plans & specifications and should be read in conjunction with the above referenced information. The selected recommendations presented in this report are intended to inform only the specific corresponding subjects. All other requirements of the above-mentioned items remain valid, unless otherwise specified. Recommendations contained in this report are based on our understanding of the proposed development and construction activities, field observations and explorations, and laboratory test results. It is possible that soil and groundwater conditions could vary and differ between or beyond the points explored. If soil or groundwater conditions are encountered during construction that differ from those described herein, or If the scope of the proposed construction changes from that described in this report, QG should be notified immediately in order to review and provide supplemental recommendations. The findings of this study are limited by the level of scope applied. We have prepared this report in substantial accordance with the generally accepted geotechnical engineering practice as it exists in the subject region. No warranty, expressed or implied, is made. The recommendations provided in this report assume that an adequate program of tests and observations will be conducted by a WABO approved special inspection firm during the construction phase in order to evaluate compliance with our recommendations. This report may be used only by the Client and their design consultants and only for the purposes stated within a reasonable time from its issuance, but in no event later than 18 months from the date of the report. It is the Client's responsibility to ensure that the Designer, Contractor, Subcontractors, etc. are made aware of this report in its entirety. Note that if another firm assumes Geotechnical Engineer of Record responsibilities, they need to review this report and either concur with the findings, conclusions, and recommendations or provide alternate findings, conclusions and recommendation. Land or facility use, on- and off-site conditions, regulations, or other factors may change over time, and additional work may be required. Based on the intended use of the report, QG may recommend that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the Client or anyone else will release QG from any liability resulting from the use of this report. The Client, the design consultants, and any unauthorized party, agree to defend, indemnify, and hold harmless QG from any claim or liability associated with such unauthorized use or non-compliance. We recommend that QG be given the opportunity to review the final project plans and specifications to evaluate if our recommendations have been properly interpreted. We assume no responsibility for misinterpretation of our recommendations. Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 19 Region & Vicinity Maps REGION VICINITY Quality Geo NW, PLLC Site Region Yelm Drive-Thru Figure 1 Source: Google Imagery, 2021 Scale & Locations are approx. Not for Construction Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 20 Exploration Map Figure 2 Source: Thurston County GIS, 2021 Scale & Locations are approx. Not for Construction 35 0 SCALE (FEET) Quality Geo NW, PLLC Site Map Yelm Drive-Thru TP-1 TP-2 TP-3 DCP-1 Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 21 Exploration Logs Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 22 Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 23 Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 24 WILDCAT DYNAMIC CONE LOG Page 1 of 1 Quality Geo, PLLC Geotechnical Consultants PROJECT NUMBER:QG21-114 Olympia, WA DATE STARTED:09-10-2021 DATE COMPLETED:09-10-2021 HOLE #:DCP-1 CREW:RG SURFACE ELEVATION:Existing PROJECT:Yelm Drive-Thru WATER ON COMPLETION:No ADDRESS:604 W. Yelm Ave.HAMMER WEIGHT:35 lbs. LOCATION:Yelm, WA CONE AREA:10 sq. cm BLOWS RESISTANCE GRAPH OF CONE RESISTANCE TESTED CONSISTENCY DEPTH PER 10 cm Kg/cm² 0 50 100 150 N'NON-COHESIVE COHESIVE -6 26.6 •••••••7 LOOSE MEDIUM STIFF -18 79.9 •••••••••••••••••••••••22 MEDIUM DENSE VERY STIFF - 1 ft 24 106.6 ••••••••••••••••••••••••••••••25+MEDIUM DENSE VERY STIFF -20 88.8 •••••••••••••••••••••••••25 MEDIUM DENSE VERY STIFF -18 79.9 •••••••••••••••••••••••22 MEDIUM DENSE VERY STIFF - 2 ft 15 66.6 •••••••••••••••••••19 MEDIUM DENSE VERY STIFF -19 84.4 ••••••••••••••••••••••••24 MEDIUM DENSE VERY STIFF -26 115.4 •••••••••••••••••••••••••••••••••25+DENSE HARD - 3 ft 27 119.9 ••••••••••••••••••••••••••••••••••25+DENSE HARD - 1 m 21 93.2 •••••••••••••••••••••••••••25+MEDIUM DENSE VERY STIFF -22 84.9 ••••••••••••••••••••••••24 MEDIUM DENSE VERY STIFF - 4 ft 25 96.5 •••••••••••••••••••••••••••25+MEDIUM DENSE VERY STIFF -14 54.0 •••••••••••••••15 MEDIUM DENSE STIFF -11 42.5 ••••••••••••12 MEDIUM DENSE STIFF - 5 ft 13 50.2 ••••••••••••••14 MEDIUM DENSE STIFF -17 65.6 •••••••••••••••••••18 MEDIUM DENSE VERY STIFF -21 81.1 •••••••••••••••••••••••23 MEDIUM DENSE VERY STIFF - 6 ft 26 100.4 •••••••••••••••••••••••••••••25+MEDIUM DENSE VERY STIFF -20 77.2 ••••••••••••••••••••••22 MEDIUM DENSE VERY STIFF - 2 m 22 84.9 ••••••••••••••••••••••••24 MEDIUM DENSE VERY STIFF - 7 ft 26 88.9 •••••••••••••••••••••••••25 MEDIUM DENSE VERY STIFF -26 88.9 •••••••••••••••••••••••••25 MEDIUM DENSE VERY STIFF -35 119.7 ••••••••••••••••••••••••••••••••••25+DENSE HARD - 8 ft 50 171.0 ••••••••••••••••••••••••••••••••••••••••••••••25+DENSE HARD - - - 9 ft - - - 3 m 10 ft - - - - 11 ft - - - 12 ft - - - 4 m 13 ft C:\My Documents\Wildcat\WC_XL97.XLS Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 25 Laboratory Results Yelm Drive-Thru - Soils Report Quality Geo NW, PLLC 10/7/2021 Project # QG21-114 26 40 1 20 40 80 GGS 601 LLC 21724141206 ix vi SECTION 24 TOWNSHIP 17 RANGE 1E PROJECT BOUNDARY I < BASIN BOUNDARY I I I I I I _M FRIENDS LLC 21724141206 1 LONGMIRE ST : LINCOLN ALEXANDRA LLC BALTIC AVE LLC 21724141502 21724141205 PRE -DEVELOPMENT BASIN TOTAL FORESTED = 0.32 TOTAL = 0.32AC GGS 601 LLC 21724141206 W R .'.VE461FKIENOSLLC.'.'.'.'.•.•.•.•.•.•.•.•.•.•.•.•.•. _-PROJCC" BOUNDARY •, .s, LONGMIRE ST i LINCOLN ALEXANDRA LLC 21724141502 I POST -DEVELOPMENT BASIN TOTAL LL W2 Y BUILDING = 0.03AC CONCRETE = 0.03AC LANDSCAPE = 0.02AC ASPHALT = 0.24AC TOTAL = 0.32AC BASIN BOUNDARY YELM FRIENDS LLC 21724141206 BALTIC AVE LLC 21724141205 LL W2 Y U w x U O m C O m N N z m W N J W N a 0 O o w a co Lo cn W a, zQQ 9,3:0 W Y Q qg U1 J � W � Q Df CD W Y 80 c:) z W LLL H O 0 a U N W W EXHIBIT 1 OF 1 WWHM2012 PROJECT REPORT default[0]2/18/2022 3:15:36 PM General Model Information Project Name:default[0] Site Name:EL Rey Site Address:604 Yelm Ave City:Yelm 98597 Report Date:2/18/2022 Gage:Lake Lawrence Data Start:1955/10/01 Data End:2008/09/30 Timestep:15 Minute Precip Scale:0.857 Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year default[0]2/18/2022 3:15:36 PM Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.32 Pervious Total 0.32 Impervious Land Use acre Impervious Total 0 Basin Total 0.32 Element Flows To: Surface Interflow Groundwater default[0]2/18/2022 3:15:36 PM Basin 1 (No Roof) Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.32 Pervious Total 0.32 Impervious Land Use acre Impervious Total 0 Basin Total 0.32 Element Flows To: Surface Interflow Groundwater default[0]2/18/2022 3:15:36 PM Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.02 Pervious Total 0.02 Impervious Land Use acre ROOF TOPS FLAT 0.03 SIDEWALKS FLAT 0.03 PARKING FLAT 0.24 Impervious Total 0.3 Basin Total 0.32 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 default[0]2/18/2022 3:15:36 PM Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.02 Pervious Total 0.02 Impervious Land Use acre SIDEWALKS FLAT 0.03 PARKING FLAT 0.24 Impervious Total 0.27 Basin Total 0.29 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 2 Trapezoidal Pond 2 Basin 1 (No Roof) default[0]2/18/2022 3:15:36 PM Routing Elements Predeveloped Routing default[0]2/18/2022 3:15:36 PM Mitigated Routing Trapezoidal Pond 1 Bottom Length:21.50 ft. Bottom Width:21.50 ft. Depth:5 ft. Volume at riser head:0.0430 acre-feet. Infiltration On Infiltration rate:8 Infiltration safety factor:1 Total Volume Infiltrated (ac-ft.):54.548 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):54.548 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0 Side slope 1:0 To 1 Side slope 2:0 To 1 Side slope 3:0 To 1 Side slope 4:0 To 1 Discharge Structure Riser Height:4 ft. Riser Diameter:20 in. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.010 0.000 0.000 0.000 0.0556 0.010 0.000 0.000 0.085 0.1111 0.010 0.001 0.000 0.085 0.1667 0.010 0.001 0.000 0.085 0.2222 0.010 0.002 0.000 0.085 0.2778 0.010 0.002 0.000 0.085 0.3333 0.010 0.003 0.000 0.085 0.3889 0.010 0.004 0.000 0.085 0.4444 0.010 0.004 0.000 0.085 0.5000 0.010 0.005 0.000 0.085 0.5556 0.010 0.005 0.000 0.085 0.6111 0.010 0.006 0.000 0.085 0.6667 0.010 0.007 0.000 0.085 0.7222 0.010 0.007 0.000 0.085 0.7778 0.010 0.008 0.000 0.085 0.8333 0.010 0.008 0.000 0.085 0.8889 0.010 0.009 0.000 0.085 0.9444 0.010 0.010 0.000 0.085 1.0000 0.010 0.010 0.000 0.085 1.0556 0.010 0.011 0.000 0.085 1.1111 0.010 0.011 0.000 0.085 1.1667 0.010 0.012 0.000 0.085 1.2222 0.010 0.013 0.000 0.085 1.2778 0.010 0.013 0.000 0.085 1.3333 0.010 0.014 0.000 0.085 1.3889 0.010 0.014 0.000 0.085 1.4444 0.010 0.015 0.000 0.085 default[0]2/18/2022 3:15:36 PM 1.5000 0.010 0.015 0.000 0.085 1.5556 0.010 0.016 0.000 0.085 1.6111 0.010 0.017 0.000 0.085 1.6667 0.010 0.017 0.000 0.085 1.7222 0.010 0.018 0.000 0.085 1.7778 0.010 0.018 0.000 0.085 1.8333 0.010 0.019 0.000 0.085 1.8889 0.010 0.020 0.000 0.085 1.9444 0.010 0.020 0.000 0.085 2.0000 0.010 0.021 0.000 0.085 2.0556 0.010 0.021 0.000 0.085 2.1111 0.010 0.022 0.000 0.085 2.1667 0.010 0.023 0.000 0.085 2.2222 0.010 0.023 0.000 0.085 2.2778 0.010 0.024 0.000 0.085 2.3333 0.010 0.024 0.000 0.085 2.3889 0.010 0.025 0.000 0.085 2.4444 0.010 0.025 0.000 0.085 2.5000 0.010 0.026 0.000 0.085 2.5556 0.010 0.027 0.000 0.085 2.6111 0.010 0.027 0.000 0.085 2.6667 0.010 0.028 0.000 0.085 2.7222 0.010 0.028 0.000 0.085 2.7778 0.010 0.029 0.000 0.085 2.8333 0.010 0.030 0.000 0.085 2.8889 0.010 0.030 0.000 0.085 2.9444 0.010 0.031 0.000 0.085 3.0000 0.010 0.031 0.000 0.085 3.0556 0.010 0.032 0.000 0.085 3.1111 0.010 0.033 0.000 0.085 3.1667 0.010 0.033 0.000 0.085 3.2222 0.010 0.034 0.000 0.085 3.2778 0.010 0.034 0.000 0.085 3.3333 0.010 0.035 0.000 0.085 3.3889 0.010 0.036 0.000 0.085 3.4444 0.010 0.036 0.000 0.085 3.5000 0.010 0.037 0.000 0.085 3.5556 0.010 0.037 0.000 0.085 3.6111 0.010 0.038 0.000 0.085 3.6667 0.010 0.038 0.000 0.085 3.7222 0.010 0.039 0.000 0.085 3.7778 0.010 0.040 0.000 0.085 3.8333 0.010 0.040 0.000 0.085 3.8889 0.010 0.041 0.000 0.085 3.9444 0.010 0.041 0.000 0.085 4.0000 0.010 0.042 0.000 0.085 4.0556 0.010 0.043 0.231 0.085 4.1111 0.010 0.043 0.653 0.085 4.1667 0.010 0.044 1.196 0.085 4.2222 0.010 0.044 1.827 0.085 4.2778 0.010 0.045 2.522 0.085 4.3333 0.010 0.046 3.255 0.085 4.3889 0.010 0.046 3.998 0.085 4.4444 0.010 0.047 4.726 0.085 4.5000 0.010 0.047 5.413 0.085 4.5556 0.010 0.048 6.037 0.085 4.6111 0.010 0.048 6.578 0.085 4.6667 0.010 0.049 7.028 0.085 default[0]2/18/2022 3:15:36 PM 4.7222 0.010 0.050 7.387 0.085 4.7778 0.010 0.050 7.668 0.085 4.8333 0.010 0.051 7.901 0.085 4.8889 0.010 0.051 8.248 0.085 4.9444 0.010 0.052 8.502 0.085 5.0000 0.010 0.053 8.749 0.085 5.0556 0.010 0.053 8.988 0.085 default[0]2/18/2022 3:15:36 PM Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.32 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.02 Total Impervious Area:0.3 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.014839 5 year 0.028034 10 year 0.040203 25 year 0.060347 50 year 0.079408 100 year 0.102485 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0 5 year 0 10 year 0 25 year 0 50 year 0 100 year 0 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1956 0.015 0.000 1957 0.047 0.000 1958 0.011 0.000 1959 0.012 0.000 1960 0.022 0.000 1961 0.013 0.000 1962 0.005 0.000 1963 0.022 0.000 1964 0.013 0.000 1965 0.014 0.000 default[0]2/18/2022 3:16:11 PM 1966 0.007 0.000 1967 0.014 0.000 1968 0.010 0.000 1969 0.006 0.000 1970 0.012 0.000 1971 0.015 0.000 1972 0.023 0.000 1973 0.013 0.000 1974 0.059 0.000 1975 0.012 0.000 1976 0.016 0.000 1977 0.004 0.000 1978 0.015 0.000 1979 0.011 0.000 1980 0.013 0.000 1981 0.022 0.000 1982 0.011 0.000 1983 0.019 0.000 1984 0.014 0.000 1985 0.006 0.000 1986 0.025 0.000 1987 0.018 0.000 1988 0.009 0.000 1989 0.010 0.000 1990 0.085 0.000 1991 0.034 0.000 1992 0.012 0.000 1993 0.006 0.000 1994 0.012 0.000 1995 0.018 0.000 1996 0.023 0.000 1997 0.018 0.000 1998 0.024 0.000 1999 0.010 0.000 2000 0.010 0.000 2001 0.004 0.000 2002 0.019 0.000 2003 0.008 0.000 2004 0.082 0.000 2005 0.116 0.000 2006 0.033 0.000 2007 0.019 0.000 2008 0.040 0.000 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1161 0.0000 2 0.0853 0.0000 3 0.0818 0.0000 4 0.0592 0.0000 5 0.0472 0.0000 6 0.0396 0.0000 7 0.0335 0.0000 8 0.0326 0.0000 9 0.0254 0.0000 10 0.0240 0.0000 11 0.0234 0.0000 default[0]2/18/2022 3:16:11 PM 12 0.0232 0.0000 13 0.0224 0.0000 14 0.0221 0.0000 15 0.0221 0.0000 16 0.0190 0.0000 17 0.0189 0.0000 18 0.0187 0.0000 19 0.0178 0.0000 20 0.0177 0.0000 21 0.0177 0.0000 22 0.0161 0.0000 23 0.0151 0.0000 24 0.0150 0.0000 25 0.0150 0.0000 26 0.0144 0.0000 27 0.0142 0.0000 28 0.0137 0.0000 29 0.0130 0.0000 30 0.0126 0.0000 31 0.0126 0.0000 32 0.0125 0.0000 33 0.0121 0.0000 34 0.0121 0.0000 35 0.0119 0.0000 36 0.0118 0.0000 37 0.0117 0.0000 38 0.0115 0.0000 39 0.0113 0.0000 40 0.0112 0.0000 41 0.0104 0.0000 42 0.0102 0.0000 43 0.0098 0.0000 44 0.0096 0.0000 45 0.0087 0.0000 46 0.0084 0.0000 47 0.0072 0.0000 48 0.0063 0.0000 49 0.0063 0.0000 50 0.0058 0.0000 51 0.0046 0.0000 52 0.0039 0.0000 53 0.0038 0.0000 default[0]2/18/2022 3:16:11 PM Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0074 14117 0 0 Pass 0.0081 11006 0 0 Pass 0.0089 8668 0 0 Pass 0.0096 6993 0 0 Pass 0.0103 5611 0 0 Pass 0.0111 4486 0 0 Pass 0.0118 3650 0 0 Pass 0.0125 2944 0 0 Pass 0.0132 2405 0 0 Pass 0.0140 1983 0 0 Pass 0.0147 1638 0 0 Pass 0.0154 1313 0 0 Pass 0.0161 1098 0 0 Pass 0.0169 901 0 0 Pass 0.0176 717 0 0 Pass 0.0183 576 0 0 Pass 0.0191 482 0 0 Pass 0.0198 398 0 0 Pass 0.0205 330 0 0 Pass 0.0212 284 0 0 Pass 0.0220 245 0 0 Pass 0.0227 205 0 0 Pass 0.0234 176 0 0 Pass 0.0241 163 0 0 Pass 0.0249 152 0 0 Pass 0.0256 137 0 0 Pass 0.0263 125 0 0 Pass 0.0271 117 0 0 Pass 0.0278 108 0 0 Pass 0.0285 97 0 0 Pass 0.0292 82 0 0 Pass 0.0300 74 0 0 Pass 0.0307 70 0 0 Pass 0.0314 61 0 0 Pass 0.0321 56 0 0 Pass 0.0329 48 0 0 Pass 0.0336 40 0 0 Pass 0.0343 35 0 0 Pass 0.0351 32 0 0 Pass 0.0358 23 0 0 Pass 0.0365 14 0 0 Pass 0.0372 10 0 0 Pass 0.0380 7 0 0 Pass 0.0387 6 0 0 Pass 0.0394 6 0 0 Pass 0.0401 5 0 0 Pass 0.0409 5 0 0 Pass 0.0416 5 0 0 Pass 0.0423 5 0 0 Pass 0.0431 5 0 0 Pass 0.0438 5 0 0 Pass 0.0445 5 0 0 Pass 0.0452 5 0 0 Pass default[0]2/18/2022 3:16:11 PM 0.0460 5 0 0 Pass 0.0467 5 0 0 Pass 0.0474 4 0 0 Pass 0.0481 4 0 0 Pass 0.0489 4 0 0 Pass 0.0496 4 0 0 Pass 0.0503 4 0 0 Pass 0.0510 4 0 0 Pass 0.0518 4 0 0 Pass 0.0525 4 0 0 Pass 0.0532 4 0 0 Pass 0.0540 4 0 0 Pass 0.0547 4 0 0 Pass 0.0554 4 0 0 Pass 0.0561 4 0 0 Pass 0.0569 4 0 0 Pass 0.0576 4 0 0 Pass 0.0583 4 0 0 Pass 0.0590 4 0 0 Pass 0.0598 3 0 0 Pass 0.0605 3 0 0 Pass 0.0612 3 0 0 Pass 0.0620 3 0 0 Pass 0.0627 3 0 0 Pass 0.0634 3 0 0 Pass 0.0641 3 0 0 Pass 0.0649 3 0 0 Pass 0.0656 3 0 0 Pass 0.0663 3 0 0 Pass 0.0670 3 0 0 Pass 0.0678 3 0 0 Pass 0.0685 3 0 0 Pass 0.0692 3 0 0 Pass 0.0700 3 0 0 Pass 0.0707 3 0 0 Pass 0.0714 3 0 0 Pass 0.0721 3 0 0 Pass 0.0729 3 0 0 Pass 0.0736 3 0 0 Pass 0.0743 3 0 0 Pass 0.0750 3 0 0 Pass 0.0758 3 0 0 Pass 0.0765 3 0 0 Pass 0.0772 3 0 0 Pass 0.0780 3 0 0 Pass 0.0787 3 0 0 Pass 0.0794 3 0 0 Pass default[0]2/18/2022 3:16:11 PM LID Report default[0]2/18/2022 3:17:46 PM Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.0402 acre-feet On-line facility target flow:0.0467 cfs. Adjusted for 15 min:0.0467 cfs. Off-line facility target flow:0.0264 cfs. Adjusted for 15 min:0.0264 cfs. default[0]2/18/2022 3:17:46 PM Appendix Predeveloped Schematic default[0]2/18/2022 3:17:47 PM Mitigated Schematic