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HomeMy WebLinkAboutRS_Stormwater_Prevention_Plan_181126_v2 SSEECCTTIIOONN 11 –– CCOONNSSTTRRUUCCTTIIOONN SSTTOORRMMWWAATTEERR PPOOLLLLUUTTIIOONN PPRREEVVEENNTTIIOONN EELLEEMMEENNTTSS Stormwater pollution prevention will be maintained during the construction of this site by incorporating standard erosion control methods such as a temporary construction entrance and mirafi siltation fences. The following devices will be used to trap sediment from the cleared areas and prevent it from leaving the site. A construction entrance will be installed at the entrance to the site to keep sediment from being tracked out of the site and onto the County roads. Mirafi silt fences will be installed along the perimeter to stop any sediment runoff from exiting the project limits. The following general Washington State Elements shall be upheld at all times during the construction process. Please reference the BMP section in this report. Element #1: Preserve Vegetation/Mark Clearing Limits  Prior to 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. These shall be marked, both in the field and on the plans, to prevent damage and offsite impacts.  The duff layer, native topsoil, and natural vegetation shall be retained in an undisturbed state to the maximum degree practicable.  Plastic, metal, or stake wire fence may be used to mark the clearing limits.  Suggested BMPs: - D.2.1.1.1: Plastic or Metal Fence Element #2: Establish Construction Access  Construction vehicle access and exit shall be limited to one route, if possible.  Access points shall be stabilized with a pad of quarry spalls, crushed rock or other equivalent BMP, to minimize the tracking of sediment onto public roads.  Wheel wash or tire baths should be located on site, if the stabilized construction entrance is not effective in preventing sediment from being tracked onto public roads. If a wheel wash is used it should be self contained. Track out is not allowed per City of Auburn Surface Water Management Manual.  Construction access restoration shall be equal to or better than the pre- construction condition. REVISION Received: 11/26/2018 / aalexander BUILDING DIVISION APPROVEDBUILDING DIVISION THIS SET OF APPROVED PLANS MUST BE ON THE JOB AT ALLTIMES DURING CONSTRUCTION. THIS BUILDING IS NOT TO BEOCCUPIED UNTIL AFTER FINAL INSPECTION BY THE RENTONBUILDING DIVISION AND RECEIPT OF CERTIFICATE OFOCCUPANCY. APPROVAL SHALL NOT BE CONSTRUED AS THE AUTHORITY TOVIOLATE OR CANCEL ANY PROVISIONS OF CODES, ORDINANCES,OR OTHER REGULATIONS ENFORCED BY THIS CITY. DATE: 12/07/2018  Suggested BMPs: - D.2.1.4.1: Stabilized Construction Entrance Element #3: Control Flow Rates  Properties and waterways downstream from development sites shall be protected from erosion due to increases in the velocity and peak volumetric flow rate of stormwater runoff from the project site, as required by local plan approval authority. Element #4: Install Sediment Controls  Stormwater runoff from disturbed areas shall pass through a sediment pond or other appropriate sediment removal BMP, prior to leaving a construction site or prior to discharge to an infiltration facility. Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but shall meet the flow control performance standard of S9.D.3.a.  Sediment control BMPs (sediment ponds, traps, filters, etc.) shall be constructed as one of the first steps in grading. These BMPs shall be functional before other land disturbing activities take place.  BMPs intended to trap sediment on site shall be located in a manner to avoid interference with the movement of juvenile salmonids attempting to enter off- channel areas or drainages.  Suggested BMPs: - D.2.1.3.1: Silt Fence Element #5: Stabilize Soils  Exposed and unworked soils shall be stabilized 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 on areas to be paved, and dust control.  Depending on the geographic location of the project, no soils shall remain exposed and unworked for more than the time periods set forth below to prevent erosion: West of the Cascade Mountains Crest: During the dry season (May 1 – Sept. 30): 7 days During the wet season (October 1 – April 30): 2 days The time period may be adjusted by a local jurisdiction, if the Jurisdiction can show that local precipitation data justify a different standard.  Soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast.  Soil stockpiles must be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels.  Suggested BMPs: - D.2.1.2.2: Mulching - D.2.1.2.4: Plastic Covering - D.2.1.2.6: Temporary and Permanent Seeding - D.2.1.2.7: Sodding - D.2.1.8: Dust Control Element #6: Protect Slopes  Design and construct cut and fill slopes in a manner that will minimize erosion. Applicable practices include, but are not limited to, reducing continuous length of slope with terracing and diversions, reducing slope steepness, and roughening slope surfaces (e.g., track walking).  Off-site stormwater (run-on) or groundwater shall be diverted 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. West of the Cascade Mountains Crest: Temporary pipe slope drains shall handle the peak 10-minute velocity of flow from a Type 1A, 10-year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis shall use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis shall use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the WWHM to predict flows, bare soil areas should be modeled as “landscaped area."  Excavated material shall be placed on the uphill side of trenches, consistent with safety and space considerations.  Check dams shall be placed at regular intervals within constructed channels that are cut down a slope.  Suggested BMPs: - D.2.1.2.6: Temporary and Permanent Seeding Element #7: Protect Drain Inlets This element is not applicable due to there being no drain inlets on or in the direct vicinity of the site. Element #8: Stabilize Channels and Outlets This element is not applicable because 100% of the stormwater will be controlled onsite via dispersion BMP’s. Element #9: Control Pollutants  All pollutants, including waste materials and demolition debris, that occur on site during construction shall be handled and disposed of in a manner that does not cause contamination of surface water.  Cover, containment, and protection from vandalism shall be provided 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 shall include secondary containment.  Maintenance, fueling, and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures. Contaminated surfaces shall be cleaned immediately following any spill incident.  Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment system or to the sanitary sewer with local sewer district approval.  Application of fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers’ label requirements for application rates and procedures shall be followed.  BMPs shall be used to prevent or treat contamination of stormwater runoff by pH modifying sources. These sources 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. Permittees shall adjust the pH of stormwater if necessary to prevent violations of water quality standards.  Permittees shall obtain written approval from Ecology prior to using chemical treatment, other than CO2 or dry ice to adjust pH.  Suggested BMPs: - D.2.2.1: Concrete Handling Element #10: Control Dewatering  If dewatering is anticipated or encountered during construction, contractor shall contact a Source Control Representative with the City of Auburn at (253) 876- 1969. Dewatering may require a Special Approved Discharge permit.  Foundation, vault, and trench dewatering water, which have similar characteristics to stormwater runoff at the site, shall be discharged into a controlled conveyance system prior to discharge to a sediment trap or sediment pond.  Clean, non-turbid dewatering water, such as well-point ground water, can be discharged to systems tributary to, or directly into surface waters of the state, as specified in S9.D.8, provided the de-watering flow does not cause erosion or flooding of receiving waters. Clean de-watering water should not be routed through stormwater sediment ponds.  Other 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 or other suitable treatment technologies; 4. Sanitary sewer discharge with local sewer district approval, if there is no other option; or 5. Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized de-watering.  Highly turbid or contaminated dewatering water shall be handled separately from stormwater. Element #11: Maintain BMPs  All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as needed to assure continued performance of their intended function in accordance with BMP specifications.  All temporary erosion and sediment control BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Element #12: Manage the Project  Development projects shall be phased to the maximum degree practicable and shall take into account seasonal work limitations.  Inspection and Monitoring All BMPs shall be inspected, maintained, and repaired as needed to assure continued performance of their intended function. Site inspections and monitoring shall be conducted in accordance with S4.  Maintaining an Updated Construction SWPPP The SWPPP shall be maintained, updated, and implemented in accordance with Conditions S3, S4 and S9. Monitoring Requirements The primary monitoring requirements are summarized in Table 3 (below): Table 3. Summary of Monitoring Requirements1 Size of Soils Disturbance2 Weekly Site Inspections Weekly Sampling w/ Turbidity Meter Weekly Sampling w/ Transparency Tube Weekly pH sampling3 Sites which disturb less than 1 acre Required Not Required Not Required Not Required Sites which disturb 1 acre or more, but less than 5 acres Required Sampling Required – either method4 Required Sites which disturb 5 acres or more Required Required Not Required5 Required 1 Additional monitoring requirements may apply for: 1) discharges to 303(d) listed waterbodies and waterbodies with applicable TMDLs for turbidity, fine sediment, high pH, or phosphorus – see Condition S8; and 2) sites required to perform additional monitoring by Ecology order – see Condition G13. 2 Soil disturbance is calculated by adding together all areas affected by construction activity. Construction Activity means clearing, grading, excavation, and any other activity which disturbs the surface of the land, including ingress/egress from the site. 3 Beginning October 1, 2006, if construction activity involves significant concrete work or the use of engineered soils, and stormwater from the affected area drains to a stormwater collection system or other surface water, the Permittee shall conduct pH sampling in accordance with Condition S4.D. 4 Beginning October 1, 2008, sites with one or more acres, but less than 5 acres of soil disturbance, shall conduct turbidity or transparency sampling in accordance with Condition S4.C. 5 Beginning October 1, 2006, sites greater than or equal to 5 acres of soil disturbance shall conduct turbidity sampling using a turbidity meter in accordance with Condition S4.C. A. Site Log Book The Permittee shall maintain a site log book that contains a record of the implementation of the SWPPP and other permit requirements including the installation and maintenance of BMPs, site inspections, and stormwater monitoring. B. Site Inspections 1. Site inspections shall include all areas disturbed by construction activities, all BMPs, and all stormwater discharge points. Stormwater shall be visually examined for the presence of suspended sediment, turbidity, discoloration, and oil sheen. Inspectors shall 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, the Permittee shall correct the problems identified as follows: a. Review the SWPPP for compliance with Condition S9 and make appropriate revisions within 7 days of the inspection; and b. Fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, but no later than 10 days of the inspection; and c. Document BMP implementation and maintenance in the site log book. 2. The site inspections shall be conducted at least once every calendar week and within 24 hours of any discharge from the site. The inspection frequency for temporarily stabilized, inactive sites may be reduced to once every calendar month. 3. Site inspections shall be conducted by a person who is knowledgeable in the principles and practices of erosion and sediment control. The inspector shall have the skills to: a. Assess the site conditions and construction activities that could impact the quality of stormwater, and b. Assess the effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. 4. Beginning October 1, 2006, construction sites one acre or larger that discharge stormwater to surface waters of the state, shall have site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL). The CESCL shall be identified in the SWPPP and shall be present on-site or on-call at all times. Certification shall be obtained through an approved erosion and sediment control training program that meets the minimum training standards established by Ecology (see BMP C160 in the Manual). 5. The inspector shall summarize the results of each inspection in an inspection report or checklist and be entered into, or attached to, the site log book. At a minimum, each inspection report or checklist shall include: a. Inspection date and time. b. Weather information; general conditions during inspection and approximate amount of precipitation since the last inspection, and within the last 24 hours. c. A summary or list of all BMPs which have been implemented, including observations of all erosion/sediment control structures or practices. d. The following shall be noted: i. locations of BMPs inspected, ii. locations of BMPs that need maintenance, iii. the reason maintenance is needed, iv. locations of BMPs that failed to operate as designed or intended, and v. locations where additional or different BMPs are needed, and the reason(s) why. e. A description of stormwater discharged from the site. The inspector shall note the presence of suspended sediment, turbid water, discoloration, and/or oil sheen, as applicable. f. Any water quality monitoring performed during inspection. g. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made as a result of the inspection. h. A statement that, in the judgment of the person conducting the site inspection, the site is either in compliance or out of compliance with the terms and conditions of the SWPPP and the permit. If the site inspection indicates that the site is out of compliance, the inspection report shall include a summary of the remedial actions required to bring the site back into compliance, as well as a schedule of implementation. i. Name, title, and signature of the person conducting site inspection; and the following statement: “I certify that this report is true, accurate, and complete, to the best of my knowledge and belief”. Reporting and Recordkeeping Requirements A. High Turbidity Phone Reporting Any time sampling performed in accordance with Special Condition S4.C indicates turbidity is 250 NTU or greater (or transparency is 6 cm or less) the Permittee shall notify the appropriate Ecology regional office by phone within 24 hours of analysis. B. Discharge Monitoring Reports 1. Permittees required to conduct water quality sampling in accordance with Special Conditions S.4.C (Turbidity/Transparency), S4.D (pH) and/or S8 [303(d)/TMDL sampling] shall submit the results to Ecology monthly on Discharge Monitoring Report (DMR) forms provided by Ecology. Permittees are authorized and encouraged to submit electronic DMRs using the “E-DMR Form” on Ecology’s Construction Stormwater web site: http://www.ecy.wa.gov/programs/wq/stormwater/constrcution/. 2. The Permittee shall submit DMR forms electronically or by mail to be received by Ecology within 15 days following the end of each month. If there was no discharge during a given monitoring period, the Permittee shall submit the form as required with the words “no discharge” entered in place of the monitoring results. If the Permittee is unable to submit discharge monitoring reports electronically, the Permittee may mail reports to the address listed below: Department of Ecology Water Quality Program – Construction Stormwater P.O. Box 47696 Olympia, Washington 98504-7696 C. Records Retention The Permittee shall retain records of all monitoring information (site log book, sampling results, inspection reports/checklists, etc.), Stormwater Pollution Prevention Plan, and any other documentation of compliance with permit requirements during the life of the construction project and for a minimum of three years following the termination of permit coverage. Such information shall include all calibration and maintenance records, and records of all data used to complete the application for this permit. This period of retention shall be extended during the course of any unresolved litigation regarding the discharge of pollutants by the Permittee or when requested by Ecology. D. Recording of Results For each measurement or sample taken, the Permittee shall record the following information: 1. Date, place, method, and time of sampling or measurement; 2. The individual who performed the sampling or measurement; 3. The dates the analyses were performed; 4. The individual who performed the analyses; 5. The analytical techniques or methods used; and 6. The results of all analyses. E. Additional Monitoring by the Permittee If the Permittee monitors any pollutant more frequently than required by this permit using test procedures specified by Condition S4 of this permit, the results of this monitoring shall be included in the calculation and reporting of the data submitted in the Permittee’s DMR. F. Noncompliance Notification In the event the Permittee is unable to comply with any of the terms and conditions of this permit which may cause a threat to human health or the environment, the Permittee shall: 1. Immediately notify Ecology of the failure to comply. 2. Immediately take action to prevent the discharge/pollution, or otherwise stop or correct the noncompliance, and, if applicable, repeat sampling and analysis of any noncompliance immediately and submit the results to Ecology within five (5) days after becoming aware of the violation. 3. Submit a detailed written report to Ecology within five (5) days, unless requested earlier by Ecology. The report shall contain a description of the noncompliance, including exact dates and times, and if the noncompliance has not been corrected, the anticipated time it is expected to continue; and the steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance. Compliance with these requirements does not relieve the Permittee from responsibility to maintain continuous compliance with the terms and conditions of this permit or the resulting liability for failure to comply. G. Access to Plans and Records 1. The Permittee shall retain the following permit documentation (plans and records) on-site, or within reasonable access to the site, for use by the operator; or on-site review by Ecology or the local jurisdiction: a. General Permit; b. Permit Coverage Letter; c. Stormwater Pollution Prevention Plan (SWPPP); and d. Site Log Book 2. The Permittee(s) shall address written requests for plans and records listed above (Condition S5.G.1) as follows: a. A copy of plans and records shall be provided to Ecology within 14 days of receipt of a written request from Ecology. b. A copy of plans and records shall be provided to the public when requested in writing. Upon receiving a written request from the public for the Permittee’s plans and records, the Permittee shall either: i. Provide a copy of the plans and records to the requestor within 14 days of a receipt of the written request; or ii. Notify the requestor within 10 days of receipt of the written request of the location and times within normal business hours when the plans and records may be viewed, and provide access to the plans and records within 14 days of receipt of the written request; or iii. Within 14 days of receipt of the written request, the Permittee may submit a copy of the plans and records to Ecology for viewing and/or copying by the requestor at an Ecology office, or a mutually agreed upon location. If plans and records are viewed and/or copied at a location other than at an Ecology office, the Permittee will provide reasonable access to copying services for which a reasonable fee may be charged. The Permittee shall notify the requestor within 10 days of receipt of the request where the plans and records may be viewed and/or copied. SSEECCTTIIOONN 22 –– CCOONNSSTTRRUUCCTTIIOONN PPHHAASSIINNGG The proposed construction sequence will be as follows: 1. Hold the pre-construction meeting with King County staff. 2. Flag or fence clearing limits. 3. Post a sign with the name and phone number of the ESC supervisor. 4. Grade and install construction entrance(s). 5. Install perimeter protection (silt fence, brush barrier, etc.) 6. Grade and stabilize construction roads. 7. Construct surface and sub-surface water controls (interceptor swales/trenches, rock check dams, etc.) simultaneously with clearing and grading for project development. 8. Maintain erosion control measures in accordance with King County requirements and manufacturer’s recommendations. 9. Relocate surface controls or erosion control measures, or install new measures so that as site conditions change, the erosion and sediment control is always in accordance with King County. 10. Cover all areas that will be un-worked for more than seven days during the dry season or two days during the wet season with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. 11. Stabilize all areas within seven days of reaching final grade. 12. Seed or sod any areas to remain un-worked for more than 30 days. 13. Upon completion of the project, stabilize all disturbed areas and remove BMP’s if appropriate. SSEECCTTIIOONN 33 –– CCOONNSSTTRRUUCCTTIIOONN SSCCHHEEDDUULLEE Construction of this project is planned to begin in the Winter/Spring of 2018, and will follow the above construction sequence. During the wet season from October 1 through March 31, no soils shall remain exposed and unworked for more than 2 days at a time. SSEECCTTIIOONN 44 –– FFIINNAANNCCIIAALL//OOWWNNEERRSSHHIIPP RREESSPPOONNSSIIBBLLIITTIIEESS The property owner responsible for the initiation of any necessary bonds and/or other financial securities is: JK MONARCH P.O. BOX 188 PUYALLUP, WA 98371 CONTACT: RUSS SORKNESS PH: (253) 840-5660 SSEECCTTIIOONN 55 –– EENNGGIINNEEEERRIINNGG CCAALLCCUULLAATTIIOONNSS Due to proposing dispersion BMP’s, formal engineering calculations are not needed. SSEECCTTIIOONN 66 –– EERROOSSIIOONN CCOONNTTRROOLL SSPPEECCIIAALLIISSTT No erosion control specialist has been appointed at this time. Once one is established, he/she will be reported to King County.