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• <br />• <br />• <br />- 9 - <br />Compaction around the outlet works should be by hand methods and should <br />consist of clay soils at or above optimum moisture content. Care will <br />be required in order to provide good compaction all the way around the <br />pipe to prevent seepage. P. staff gauge could be provided on the <br />sliding gate shaft. <br />Spillway: Placement of the spillway on the south end of the ~an!cnent <br />would allow discharge at the downstre;~m end of Iiayden Gulch. This <br />would allow possibly a smaller channel secticn for Yayden Gulch a; well <br />as bypassing the toe of the dam with overflow. There will be some <br />settlement beneath the spillway; however, thi=_ could be compensated by <br />overbuild or remedial construction. Eoth the upstream area imrmediately <br />ahead of the spillway and the downstream partion all across the dam <br />must be protected with riprap or slope :mattress. This is necessary to <br />prevent erosion of the emban~ament. Details of slope protection are <br />discussed below. <br />Slope Protection: It is anticipated that coarse rock from the over- <br />burden excavation will be used for slope protection. This will be used <br />both as filling for mattress gabions as well as the loose riprap. <br />because of the large difference between the gradation of the fine- <br />grained dam materials and the riprap, some type of filter bed or filter <br />fabric will be required zs a transition. If a filter fabric is used. <br />care must b~ exercised in protecting it during placement of the loose <br />riprap. Riprap materials should be the most durable encountered in the <br />excavation. It should he a hard, dense material conforming to the <br /> <br />~ _ _. <br />