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~APA Parts warehous~, are located in ti,e path of flooding. Hydrological investigations indicate that with the present degree of development in the Weir Gulch Basin and the existing facilities at Barnum Lake, approximately 2,400 cfs would flow out of the Weir Gulch Basin and easterly along the 6th Avenue area during a 100 year storm occurrence. In comparison, only 900 cfs would flow beneath 6th Avenue in the Weir Gulch culverts and continuo on down the historic path of weir Gulch. Oiscussions with legal counsel indicate that the public agencies responsible for construction of the 6th Avenue Freeway might be held responsible for damages resulting from flow which left the natural channel of Weir Gulch and proceeded down 6th Avenue. Hydrological studies indicated that the existing conduits beneath 6th Avenue are capable of carrying only slightly in excess of the 5 year storm occurrence runoff. Greater storm occurrences would be expected to flow across Federal and down 6th Avenue. " I I SANDERSON GULCH Both the Ward Lateral and Welch Ditch cross the Sanderson Gulch Basin just above Smith Reservoir. Both ditches have been placed in conduit in several areas due to recent construction and do not represent major drainage constraints in this area. The upper 255 acres of Sanderson GVlch is intercepted by Smith Reservoir, an irrigation storage reservoir owned by the Agricultural Ditch and Reservoir Co. The surface area of Smith Reservoir equals approximately 58 acres. A new spillway was constructed on Smith Reservoir recently to comply with the State Engineer's requirements. This spillway, located at the northeast corner of the reservoir, directs overflow into a channel ~nd thence to a chute along the east face of the dam terminating in a junction box at the present out- let works of the reservoir. The jUnction box directs flow from either the outlet works or the spillway of Smith Reservoir into an irrigation ditch flowing into East Reservoir which is located in the weir Gulch Basin. This is effectively a transbasin diversion which would convey storm waters to Weir Gulch Basin during over- flows of Smith Reservoir. The operational sequence of Smith Reservoir also has an effect on East Reservoir and hence Weir Gulch. Smith Reservoir normally feeds directly to East Reservoir. If this discharge is allowed to continue through a major storm event. the effect would be to continually in- crease the inflow to East Reservoir. The problems surrounding East Reservoir and operational sequences of Main and Smith Reservoirs has previously been discussed in this section. KendriCk Reservoir is located immediately on the main channel of Sanderson Gulch. east of Smith Reservoir The reservoir is owned -14- by the Foothills ~etropolitan Recreation and Park District and is utilized as a recreation reservoir only. The reservoir has a surface area of approximately 31 acres and acts as an efficient routing reservoir on Sanderson Gulch_ Only 118 acres are directly tributary to the reservoir below Smith Reservoir. The existing spillway is adequate to pass a 100 year storm. llowev7r, the reservoir would not meet existing State Englneer requlrements since the spillway crest is less than 5 feet below the dam crest. Kendrick Lake No. 1 is located on the south branch of Sanderson Gulch just south of Smith Reservoir. The lake historically acted as an irrigation storage reservoir but has recently been purchased by the foothills Metropolitan Recreation and Park District for development as a park. The reservoir has historically intercepted runoff from 44 acres and totally impounded this runoff for storms up to 100 year frequency. The hydrology for Sanderson GulCh is based upon the continued existence of this reservoir as a deten- tion facility although its character may be totally changed from an irrigation storage reservoir to a park type development. Continuing downstream on Sanderson Gulch, the Agricultural Ditch is the next major irrigation facility encountered. The ditch crosses the main gulch in a channel raised above the Jewell Park Pond. No facilities are provided for rejecting or accepting flows from Main Sanderson Gulch, so that major storm flows from Sanderson Gulch would eventually enter the ditch and could cause flooding along a major portion of the ditch. The Jewell Park Pond is a recreational pool located in a park be- longing to the city of Lakewood. The pond is relatively small, having a surface area of approxima~elY ~.7 ~cres. A small concrete spillway, 10 feet wide by 2 feet h~gh, ~s sltuated at the south- east corner of the pond. Hydrological investigations indi.cate ~hat the entire da~ crest would be overtopped hy a 10 year Btorm under existing conditions of development within the basin. Continuing downstream on Sanderson Gulch the next site encountered which is considered a reservoir is the Green Gables Country club Road. Although not specifically planned as a reservoir, the ~ery small conduits under the entrance road have the effect of back~ng up waters from any but the most minor storm runoff. Hydrological investigations indicate that the entrance road would be overtopped by a 5 year storm with existing conditions of development in the basin. 3inee ~he prescnt con~tructicn of thc entrance read i~ nct sufficient to guarantee against failure of the road embankment once overtopp~d, it is feasible that the approximately 14 acre feet of water stored behind the entrance road might be released as a flood wave if the embankment fails. The Shwayder Pond is located immediately downstream of the Green Gables entrance road. This pond is actually by-passed by the no~mal low flow of Sanderson Gulch via a 42 inch reinforced concrete plpe -1 ~-