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2021-8-30_Ecology August 30, 2021 Lori Barlow, AICP Senior Planner City of Spokane Valley 10210 E. Sprague Ave. Spokane Valley, WA 99206 Re: Painted Hills PRD, File: PRD-2015-0001, SUB-2015-0001, EGR-2016-0066, FPD-2016-0007 Dear Lori Barlow: Thank you for the opportunity to comment on the Draft Environmental Impact Statement regarding the redevelopment of an approximately 99.5-acres former golf course, by constructing 300 single- family homes and 280 multi-family units, to include a neighborhood commercial center, green space, streets and associated utilities and amenities (Proponent: Whipple Consulting Engineers, Black Realty and Northwest Renovators Inc.). After reviewing the documents, the Department of Ecology (Ecology) submits the following comments: Hazardous Waste and Toxics Reduction Program-Andrew Maher (509) 329-3612 Please keep in mind that during the construction activities associated with the Painted Hills PRD Project, some construction-related wastes produced may qualify as dangerous wastes in Washington State. Some of these wastes include:  Absorbent material  Aerosol cans  Asbestos-containing materials  Lead-containing materials  PCB-containing light ballasts  Waste paint  Waste paint thinner  Sanding dust  Treated wood You may find a more comprehensive list, as well as a link to identify and designate your wastes on the Common Construction and Demolition Wastes website at https://ecology.wa.gov/Regulations-Permits/Guidance-technical-assistance/Dangerous-waste- guidance/Common-dangerous-waste/Construction-and-demolition. The applicant, as the facility generating the waste, bears the responsibility for all construction waste. The waste generator is the person who owns the site. Even if you hire a contractor to conduct the demolition or a waste service provider to designate your waste, the site owner is ultimately liable. This is why it is important to research reputable and reliable contractors. Lori Barlow August 30, 2021 Page 2 In order to adequately identify some of your construction and remodel debris, you may need to sample and test the wastes generated to determine whether they are dangerous waste. For more information and technical assistance, contact Andrew Maher at (509) 329-3612 or andy.maher@ecy.wa.gov. Shorelands and Environmental Assistance Program-Lynn Schmidt (509) 329-3413 The terms “stormwater” and “floodwater” are used synonymously throughout the document. It would help to differentiate on-site stormwater generated from the development vs. floodwaters from the Chester Creek watershed to identify and understand the various water management infrastructures and associated regulations. Critical hydro geologic information necessary to design the infiltration facilities is missing. The estimated infiltration rates in this DEIS are likely too high considering the volume of water to be infiltrated in a relatively small area. Analysis such as groundwater mounding and the cumulative effects of multiple drywells and infiltration galleries in close proximity must be conducted before the size of the facilities can be calculated. Other methods are available than a full-scale drywell test. Regional stormwater manuals are not necessarily appropriate for designing flood control facilities. Additionally, the SVRP aquifer surface can fluctuate nearly 20 feet in a given year in this area, so timing of subsurface testing vs. the anticipated occurrence of flooding is important. It is improbable that the City can feasibly approve a PRD, grading plan, or sign the FEMA Community Acknowledgement Form without this information. The Community Acknowledgement Form certifies that the development will meet all local floodplain management standards, and that cannot be determined without sufficient data to size the facilities. Page 19 states that “this DEIS contemplates and addresses the range of environmental effects that can be expected to result from the range of infiltration test results” so that any change to the proposal resulting from the CLOMR process would likely not require additional SEPA review. The infiltration rates could very likely be well outside of this range with proper full scale and groundwater mounding analysis. The Chester Creek channel and levee are not included in the hydraulic and hydrologic analysis. As this is a major component of the overall system and is impacted by the development, it should be included. The DEIS states that there is no impact to the SVRP aquifer. In the existing condition, floodwaters slowly infiltrate and filter through fine soils over a longer period. The proposal is to inject a large volume of floodwaters and stormwater much more quickly than the current condition. It is improbable that a bio filtration swale will treat all floodwaters, let alone that the vegetation and grasses may be dormant during flood events. Please include probable impacts to the SVRP aquifer. Figure 3-8 shows the existing and future floodplain. Infiltration facilities and drainage infrastructure would still be considered floodplain areas, so those should be included. The southern and western portions of the site are still shown to be in the floodplain. Multi-family residential units and possibly estate lots are located in these areas. Please either revise the proposed floodplain area if incorrect or address the development in the floodplain. Lori Barlow August 30, 2021 Page 3 A detailed stormwater plan will need to be developed for the full project area that meets the current regulations (i.e. 2019 SWMMEW). Stormwater designs may need to follow the SWMMEW instead of the SRSM since there have been changes in the SWMMEW that are not reflected in the SRSM. There is little detail in the DEIS. The Eastern WA LID Guidance Manual is referenced; however, that document is phasing out and the information from that document is now included in the 2019 SWMMEW. The proposal implies that all runoff will remain on-site and not discharge off the property. With this amount of infiltration, it may be difficult to get that amount of water successfully into the ground. Comments on the Storm Drainage Report for Frontage Improvements: Table 2 calculates the amount of treatment volume required using a method described in the SRSM (1815 method). In this calculation, the PGIS area draining to the treatment BMP is used. In the SRSM, the language used for the calculation is the “hydraulically connected impervious area to be treated (acres)”. This differs from the value used in the report, so the BMPs are undersized. This is a serious issue and needs to be addressed. It appears that the runoff from Dishman-Mica Rd will not be treated since it drains away from the property and “cannot be effectively captured.” If there is new or replaced impervious surface on that road, it needs to be addressed, or apply additional treatment to other impervious surfaces along the roads. On page, 5 of 6, off-site times of concentration in terms of hours are discussed. Since this study involves the roadways adjacent to the project site, the times of concentration seem overly long. The basin areas are small and should have short times of concentration. Flood issues may be confused with stormwater control issues. It is unclear how the outflow rate from the infiltration areas for the 50-year storm analysis was calculated. A different rate is used in several of the basins, but there is no explanation of how the rate used was determined. This value depends on the infiltration area and the site- specific infiltration rate. For technical assistance or additional information, please contact Lynn Schmidt at (509) 329- 3413 or via email at Lynn.Schmidt@ecy.wa.gov. Solid Waste Management Program-Martyn Quinn (509) 329-3435 The applicant proposes to demolish an existing structure in the construction activities involved with the Painted Hills PRD project. Section B.7.a of the SEPA checklist asks if any environmental health hazards exist could occur as a result of the proposal. Improper disposal of solid waste, including demolition waste, can result in environmental health hazards. Ecology encourages the applicant to salvage, reuse, and recycle as much of the waste as possible. Recycling demolition debris typically costs less than disposal. Otherwise, the applicant must dispose of demolition waste at a permitted solid waste facility. For more information, please contact Martyn Quinn at (509) 329-3435 or via email at Martyn.Quinn@ecy.wa.gov. Lori Barlow August 30, 2021 Page 4 Toxics Cleanup Program-Ted Uecker (509) 329-3522 Historic use of the Painted Hills PRD project site as a golf course may have resulted in the release of hazardous substances such as petroleum hydrocarbons, heavy metals, pesticides, and herbicides into the soil and groundwater. Areas where these releases are likely to occur include landscaped putting greens, fairways, drainage basins, and equipment or chemical storage facilities. Any release, known or discovered at the site must be reported to Ecology as required by the Model Toxics Control Act. This information should be passed on to the proponent and/or property owner. For more information or technical assistance, please contact Ted Uecker at (509) 329-3522 or via email at Ted.Uecker@ecy.wa.gov. Water Quality Program-Shannon Adams (509) 329-3610 Ecology acknowledges that the applicant will obtain a Construction Stormwater General Permit, as stated in Section A.10 of the SEPA Checklist, and agrees a permit is required. For more information or technical assistance in obtaining a Construction Stormwater General Permit, please contact Shannon Adams at (509) 329-3610 or via email at Shannon.Adams@ecy.wa.gov. Water Resources Program-Dam Safety Office-Charlotte Lattimore (360) 407-6066 Under RCW 90.03.350, a Dam Safety construction permit is required for those dams or ponds, which can impound a volume of 10 acre-feet or more of water or other liquids above ground level. The Painted Hills PRD development references stormwater ponds as part of the project. To determine if Ecology will require a Dam Safety construction permit for your project, the applicant must submit a set of construction plans to: WA Department of Ecology Dam Safety Office P.O. Box 47600 Olympia, WA 98504-7600 For more information, please contact Charlotte Lattimore by e-mail at (360) 407-6066 or via email at Charlotte.Lattimore@ecy.wa.gov. State Environmental Policy Act (SEPA) Ecology bases comments upon information submitted for review. As such, comments made do not constitute an exhaustive list of the various authorizations you may need to obtain, nor legal requirements you may need to fulfill in order to carry out the proposed action. Applicants should remain in touch with their Local Responsible Officials or Planners for additional guidance. To receive more guidance on or to respond to the comments made by Ecology, please contact the appropriate staff listed above at the phone number or email provided. Department of Ecology Eastern Regional Office (Ecology File: 202103907) cc: Todd Whipple, Whipple Consulting Engineers Inc.