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_~_ ~i !~ !~~ TUTTLE APPLEGATE RINDAHL, INC. .'~ Consultants for Land and Resource Development T+tr. Sohn Doerfer mired Land f2eclamation Division July c2, 1988 Page c 4. Creek bottom is an unf•~r•t+anate use of words. Since the valley floor is very flat it sontet intes i•~oks as if it aIi i=.:> cr^eek. bottom when the creek itself is only a few feet wide at the most. Rny stockpiles piaceU along the valley floor'• will be lt~cated in alignment with the direction of flood f lt~ws. These stockpiles will be Iocat ed to the siUes of L'tt rr:> valley in ti-te Flood fringe and would only be impacted oy a severe storm event such as the I~tD year flog U. St•~ck.pi ies:: wi l I ~~nly be located in areas where fl~~•7d fl•~ws woul^ be less than 'c' feet in depth and velocities less than c feel; per second during a 100 year event. T'odsoil left for more than one year in a stockpile wits be r•eseedeU to br•ovidea erosion protection. Therefore, we oelieve that a1I stock.pi les IocateU in the lowlands area are adeeuately pr+~t acted. 5. Stream flows in Coal Cree R. are nvt large in this area, R preliminary analysis of the area hydrolony inUicates at^. average annual yield of 1, wtD0 acre-feet for the 46 square miles of drainaoe basin. This tr•atnslates int~~ an aver•aeea annual flow •~F 1.8 cfs. Coal Cr^ee~~. is ephenrer•al in nat~_tr•e a tnU goes under•or•ound for• a nra~or• poet ion •~f the year. Sediment transport is negligible for• this stream. Enclosed is a Ietter• r•epor•t given to the Urban Dr•ainaoe atnd Fiooe:! Contr••~I Dist r•ict which addressed this issue. Basically, t•~ have a pro6Lent with seUintent transp•~r•t in a str•eant, yo+a haver tt~ have enough flow t~~ over-c~-+nte tractive forces. Rs sn~~wn by the preliminary hydroL~oy, this basin Ooes not eenerateta enough water to make sediment an issue. I would point out that the Urban Dr•ainae_e and F1ooU Control Distt^ict c•~nc+ars:; on this p•~int.