Washington State Dept. of Ecology 3/27/2025

SSLAP – Lowell Snohomish River Road Agricultural Land ______________________________________________________________________________ ______________________________________________________________________________ 5 Staging and Storage Areas Staging areas are intended for short-term storage and consist of a location or locations on site where biosolids can be delivered and then loaded into application equipment. Biosolids will be off loaded onto the surface of the ground at predetermined sites on the application area of the permitted field. Centralized locations will be chosen that provide relatively convenient areas for off-loading, loading onto application equipment, close proximity to application sites, and minimal potential for environmental degradation. Biosolids Application Methods Biosolids will be applied in semi-solid form (>28% solids) using standard agricultural equipment. Sno-Valley Farms, a private contractor with extensive experience in silviculture and agricultural applications, will apply the biosolids. Biosolids will be stockpiled on the surface of the ground, loaded into a side or rear discharge spreader, and uniformly spread over the surface of the ground before incorporation by tilling. Routine equipment maintenance and cleaning are conducted on all applications’ related equipment. All haul vehicles and equipment will be free of loose biosolids prior to leaving application areas. Applications will be suspended if weather or soil conditions make operations infeasible or unsafe. Access Restrictions Signs surrounding the site prohibit public access to the application site at any time. Buffers Buffers are strips of land around storage areas or application areas that are not intended to receive biosolids. Buffers are used to protect features such as surface water or wells that may be adversely impacted by nutrient laden run off water or to minimize the potential for nuisances such as odors from biosolids stockpiles. A list of buffers for a number of features is provided in Appendix D. Out of the 165 acres, approximately 124 acres can receive biosolids when considering the appropriate buffers. Buffer distances and locations will be identified for all significant features on each site with traffic cones, stakes with flagging, or disk implement to form rows. Site Monitoring Monitoring of project operations and local environmental conditions will occur as needed. Monitoring of soil nitrate may occur to verify or refine the target application rate. Record keeping and reporting will occur as required by regulations, however, both the Federal biosolids rule, 40 CFR Part 503, and the Washington State Biosolids Management Rule, WAC 173-308, do not require routine monitoring or data reporting of soils, ground, or surface waters. In part this reflects that biosolids metal pollutant concentration limits (Table 3 of WAC 173-308-160) have been set such that biosolids concentration less than Table 3 limits should pose no significant adverse environmental risks or impacts.