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CONSTRIICTION OF VEGETATED SWALE9: <br /> Prepare the swale Por sod immediately after it has been <br /> graded. Roughen the bottom and sides of the swale by <br /> raking, place 4" (minimum) of topsoil, and fertilize with an <br /> appropriate fertilizer at the rate of 7 lbs per 1000 square <br /> feet before laying the sod. In general, use a 10-20-20 (N- <br /> P-K) fertilizer. However, use a non-nhosnho »� containina <br /> ferttlizer if the swale is beina constructe� in the Silver <br /> �ake Drainaae basin. <br /> E: Topsoil shall meet the standard for Topsoil Type A, <br /> as specified in section 9-14.1(1) of the 1991 Standard <br /> Specifications for Road, Bridge, and Municipal Construction <br /> ;WSDOT, APWA) with the following modification - 100$ of the � <br /> Yapsoil shall pass through a 1/2" siave. � <br /> Sod the swale immediately after the sides and bottom of the <br /> swale have been prepared. Lay sod to a minimum of 1.0 feat <br /> of vertical depth above the bottom of the swale. Anchor the <br /> sod in place in the bottom of the swale and to 1.0 feat of <br /> vertical depth above the bottom of the swale with stakes, <br /> metal staples or other mear.s. <br /> OTB: Lay the sod pieces with their long axis perpendicular <br /> to the direction of flow in the swale, and stagger the � <br /> pieces to avoid a continuous longitudinal seam in the bottom <br /> of the swale. <br /> Hand-seed or hydroseed the swale with the specified seed mix <br /> in addition to soddinq. If the swale is completed between <br /> April 1 and September 1, hand-seed the swale immediately. <br /> If the swale is completed between September 1 and April 1, <br /> hand-seed after April 1, but before April 30, of the spring <br /> following completion. Disperse 5 lbs of seed per 1000 <br /> squarE feet evenly over the sod and all bare areas of the <br /> swale. ' <br /> To plant wetland vegetation required for biofiltration <br /> swales, punch holes in the sod with a bar or stake <br /> approximately equivalent to the diameter of the plants� root <br /> wads. Insert the plants in the holes and tamp the sod and <br /> earth down around the plants. Locate the plants in the <br /> bottom of the swale only and in a staggered pattern - not in <br /> a straight line. <br /> NOTE: Wetland vegetation planted after March 15 will <br /> require irrigation through the first summer to ensure plant <br /> viability. Wetland �lants ideallv ahould be planted betveen <br /> October and March. <br /> � <br />