1710 W MARINE VIEW DR 2024-01-03

. PAM designated for these uses should be "water soluble" or "linear" or "non-crosslinked". Cross -linked or water absorbent PAM, polymerized in highly acidic (pH<2) conditions, are used to maintain soil moisture content. . The PAM anionic charge density may vary from 2-30 percent; a value of 18 percent is typical. Studies conducted by the United States Department of Agriculture (USDA)/ARS demon- strated that soil stabilization was optimized by using very high molecular weight (12-15 mg/ - mole), highly anionic (>20% hydrolysis) PAM. . PAM tackifiers are available and being used in place of guar and alpha plantago. Typically, PAM tackifiers should be used at a mixing rate of no more than 0.5-1 lb. per 1000 gallons of water in a hydromulch machine. Some tackifier product instructions say to use at an applic- ation rate of 3 — 5 Ibs per acre, which can be too much. In addition, pump problems can occur at higher application rates due to increased viscosity. Maintenance Standards . PAM may be reapplied on actively worked areas after a 48-hour period. . Reapplication is not required unless PAM treated soil is disturbed or unless turbidity levels show the need for an additional application. If PAM treated soil is left undisturbed, a reapplic- ation may be necessary after two months. More PAM applications may be required for steep slopes, silty and clayey soils (USDA Classification Type "C" and "D" soils), long grades, and high precipitation areas. When PAM is applied first to bare soil and then covered with straw, a reapplication may not be necessary for several months. . Loss of sediment and PAM may be a basis for penalties per RCW 90.48.080. . PAM may affect the treatment efficiency of chitosan flocculent systems. BMP C130: Surface Roughening Purpose Surface roughening aids in the establishment of vegetative cover, reduces runoff velocity, increases infiltration, and provides for sediment trapping through the provision of a rough soil surface. Hori- zontal depressions are created by operating a tiller or other suitable equipment on the contour or by leaving slopes in a roughened condition by not fine grading them. Use this BMP in conjunction with other BMPs such as BMP C 120: Temporary and Permanent Seed- ing, BMP C121: Mulching, or BMP C124: Sodding. Conditions for Use . All slopes steeper than 3H :1 V and greater than 5 vertical feet require surface roughening to a depth of 2 to 4 inches prior to seeding. . Areas that will not be stabilized immediately may be roughened to reduce runoff velocity until seeding takes place. 2019 Stormwater Management Manual for Western Washington Volume 11 - Chapter 3 - Page 307