2320 RAILWAY AVE INTERWEST CONSTRUCTION INC 2023-06-12

INTERWEST — EVERETT CONTRACTOR'S YARD INTERIM FILL PROJECT Sitts & Hill Engineers, Inc. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN Job Number 17,733 compaction. Backblading or smoothing of slopes greater than 4H:1 V is not allowed if they are to be seeded. Restoration -based landscape practices require deeper incorporation than that provided by a simple single -pass rototilling treatment. Wherever prac- tical, initially rip the subgrade to improve long-term permeability, infiltration, and water inflow qualities. At a minimum, permanent areas shall use soil amendments to achieve organic matter and permeability performance defined in engineered soil/landscape systems. For systems that are deeper than 8 inches complete the rototilling process in multiple lifts, or prepare the engineered soil system per specifications and place to achieve the specified depth. - Fertilizers: . Conducting soil tests to determine the exact type and quantity of fertilizer is recommended. This will prevent the over -application of fertilizer. . Organic matter is the most appropriate form of fertilizer because it provides nutrients (including nitrogen, phosphorus, and potassium) in the least water- soluble form. . In general, use 104-6 N-P-K (nitrogen -phosphorus -potassium) fertilizer at a rate of 90 pounds per acre. Always use slow -release fertilizers because they are more efficient and have fewer environmental impacts. Do not add fer- tilizer to the hydromulch machine, or agitate, more than 20 minutes before use. Too much agitation destroys the slow -release coating. . There are numerous products available that take the place of chemical fer- tilizers. These include several with seaweed extracts that are beneficial to soil microbes and organisms. if 100 percent cottonseed meal is used as the mulch in hydroseed, chemical fertilizer may not be necessary. Cottonseed meal provides a good source of long-term, slow -release, available nitrogen. - Bonded Fiber Matrix and Mechanically Bonded Fiber Matrix: . On steep slopes use Bonded Fiber Matrix (BFM) or Mechanically Bonded Fiber Matrix (MBFM) products. Apply BFM/MBFM products at a minimum rate of 3,000 pounds per acre of mulch with approximately 10 percent tackifier. Achieve a minimum of 95 percent soil coverage during application. Numer- ous products are available commercially. Installed products per man- ufacturer's instructions. Most products require 24-36 hours to cure before rainfall and cannot be installed on wet or saturated soils. Generally, products ' come in 40-50 pound bags and include all necessary ingredients except for seed and fertilizer. ' 2014 Stormwater Management Manual for Wester Washington ' Volume ll - Chapter 4 - Page 283 S►TTS & HILL ENGINEERS, INC. 35 ' TACOMA, WASHINGTON