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I I I I I I I I I I I I I I I I I I I .-.., ..\ , . Bootleg Reservoir Dam October 21, 1982 Page 3 runs downstream of and para 11e1 to the downstream toe of the dam to the left of the outlet works. That portion of the dam to the right of the outlet we rks is somewhat steeper be- ing at a fairly uniform slope of approximately 2:1. This portion of the structure is also affected to a minor extent by cattle traffic, but is otherwise well protected by adequate vegetative growth. On all portions of the downstream slope, limited rodent activity could be seen. Some of the rodent actiVity appeared to be caused by fairly large rodents. Con- sideration should be given to initiating a rodent control program on this dam to assure that the rodents do no further damage to the embankment structure. Seepaqe Observations -- No seepage was noted celow this structure. The lack of seepage can be attributed to the lack of storage within the basin and the extended period of time since the last storage was experienced. Outlet Works -- The outlet works consists of a wet well type installation with two vertical gates located at the upstream shoulder of the crest near the maxi- mum section of the embankment. The upstream end of the outlet conduit is pro- tected cy a trash rack structure. At the time of this inspection, this trash rack was ocscured by debris which had collected on the rack during the flood of September 14. Apparently, during the flood, a stack of straw bales was carried away cy the flood. Many of these straw bales were stuck on the upstream trash rack as well as .ceing located on the perimeter of the reservoir basin. During this inspection, this debris on the trash rack was lit in an effort to burn the debris off and clear the trash rack. Maintenance personnel from the Henrylyn Irrigation District annua lly maintained the two outlet gates on this dam to assure their continued operacility. According to Mr. Gerkin, these gates are operated through their full operating range at least once per year to assure that the gates remain operable. Spillway -- Natura I spillways exist on this structure. The main spillway is located upstream of the right abutment. Flows from this spillway will flow east away from the reservoir basin,turning tothe northto rejOin the Box Elder streamchannel well downstream of the dam. This spillway provides approximately 12 feet of freeboard to the dam,having a cottom width of approximately 50 feet. However, with increased stage in the reservoir, the spillway channel widens appreciably providing an ex- . tensive flow area over the natural terrain. According to Mr. Gerkin, a second spillway channel exists near the southwest corner of the reservoir l::a sin. This natura I spillway' would allow flows into the drainage area lying to the west of the reservoir basin. Flow through this spill- way would remain in this channel running parallel to the Box Elder stream drain- age to a point just north of Highway 52 where they would again rejoin the Box Elder channel. In'the history of the reservoir, no flows have occurred through this second spillway area.