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In which <br />L~ = length of side channel spillway crest <br />Ap area of pit measured in square feet at the high water <br />line <br />Riprap with the grouted riprap rundown on the pit sideslope may <br />be used to stabilize the spillways. Construction of this type <br />of spillway stabilization must conform to the requirements in- <br />dicated in Figure 2.8. The river bank should be stabilized in <br />accordance with the requirements of Section 2.3 - Riverbank <br />Protection. The crest of the spillway will be vegetated and <br />shall have a 10-foot wide stabilized maintenance access trail <br />along the entire length of the spillway. The objective is to <br />provide a smooth flat driving surface with the ramps between <br />top of berm and spillway bottom being no steeper than 10 per- <br />cent. Access ramps, if sloped different than the side slopes <br />of the spillway shall not protrude into the bottom width of the <br />spillway. The pitside rundown slope will be protected using <br />Type GM grouted riprap. Grout used for the grouted riprap por- <br />tion of this structure shall have a minimum compressive <br />strength of 2,000 psi. A concrete mix having 3/4-inch maximum <br />aggregate, 4-inch slump and 2,000 psi - 28 day compressive <br />strength may be substituted for grout. The grout shall be <br />placed in a manner which ensures that all voids within the en- <br />tire riprap mass are filled with grout. <br />Concrete may be used to protect spillways through riverside <br />banks. The design of the concrete shall include consideration <br />of all forces which may be encountered including, but not <br />limited to, uplift forces and pore pressures generated by <br />underlying materials. The river banks shall be protected in <br />accordance with the requirements of Section 2.3 - Riverbank <br />UD6FCD GRAVEL GUIDELINES 12/17/87 <br />2-21 <br />