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, , Reservoir are then directed into the Main Agricultural Ditch which traverses the entire study area in a north-south direction. East Reservoir presently has only a grassed swale as a spillway. The Colorado State Engineer's office has required that an ade- quate spillway be constructed on East Reservoir to pass the probable maximum precipitation storm runoff. Plans for this spillway have been completed and delivered to the State Engineer for approval. The spillway would be located in the present loca- tion of the outlet works to the reservoir and the discharge would flow along the present outlet channel and into the Agricultural Ditch. The operational characteristics of East Reservoir are of extreme importance to drainage design within the Weir Gulch Basin. Norm- ally, flows are released from Main Reservoir and Smith Reservoir into East Reservoir whiCh acts as a regulatory reservoir prior to releases into the Agricultural Ditch. If the releases from Main and Smith Reservoirs were allowed to continue throughout a major storm occurrence, the release from East Reservoir might represent the total of these two base flows plus the routed ~pillway dis- charge. It is imperative that operational procedures be set up between the City of Lakewood and the Agricultural Ditch and Reser- voir Co. to insure that the discharges from Main Reservoir and Smith Reservoir are shut down during major storm occurrences. Since the drainage basins tributary to all three mentioned reser- voirs are small enough that short duration storms can become criti- cal, the operational sequence would have to be capable of function- ing within 30 minutes of the beginning of a major storm occurrence. ; ! , I I I I , I I 1 I Review of correspondence between the Agricultural Ditch and Reser- voir Co. and the City of Lakewood re"ealod that the Agricultural DitCh and Reservoir Co. had agreed to leave two feet of freeboard in East Reservoir for the disposition of drainage waters in connec- tion .....ith the Wood Brot.her!; development of land situated below the reservoir. There was no formal agreement, but this arrangement was made in the written option by Wood Brothers to purchase the real estate from the Agricultural DitCh and Reservoir Co. Analysis of design flow routing through the proposod spillway of East Reservoir indicates that enforcement of this agreement is no longer necessary so long as the proposed spillway is constructed and the outlet conduit remains open to Agricultural Ditch. The main Agricultural DitCh flows from north to south across the ~Luuy dr~a directly below Main and East Reservoirs. Local drain- age from much of the areas situated above th~ Agricultural Oitch is intercepted by the ditch. Although the Ditch Co. presently takes the stand that they will not accept any runoff in excess of historic amounts, it is diffcult, if not impossible, for the Ditch Co. to refuse runoff waters entering the ditch due to overland flow. Tn addition, a 42 inch corrugated metal pipe has been constructed -12- from the intersection of Kipling Street and Mississippi Avenue directly to the Agricultural Ditch. A memorandum from the Agricultural Ditch and Reservoir Co. dated December 1, 1970 indicates that the installation of this pipe was allowed only as a temporary measure until other points of discharge were made available by the City. Kount:z;e Lake is located approximately 1/4 mile west of Wadsworth Blvd. and 1/4 mile north of the main channel of Weir Gulch. The lake is not located on the main gulch but intercepts a 212 acre sub-basin. The present outlet to the reservoir is a small gated pipe which discharges directly to Wei~ Gulch. Normal.re~eases from the reservoir have historically been Ln the form of LrrLgation flows to ditches used on the Belmar Estates. Development is rapidly pro- ceeding on the fringes of the lake and its use as an irrigation reservoir has ceased to exist. In response to a letter dated February 11, 1972 from the City of ~akewood, Frasier & Gingery, Inc. presented preliminary data to the CLty of Lakewood to the effect, that 28 acre feet of storage should be maintained in the reserVOLr to continue its effect of totally storing the 100 year storm occurrence. Hydrology for the Weir Gulch Basin is founded upon the premise that Kountze Lake will continue to intercept and totally store the 100 year storm runoff for future release at a greatly diminiShed rate. The Rocky Mountain Ditch, flowing in a north to south direction, crosses Weir Gulch between Pierce Street and Harlan Street. The ditch is relatively small in comparison to Agri~ultural ~itch; however, it is subject to the same prob~ems of Lnt~rceptLng over- land flow as is the main Agricultural DLtch. The dLtch crosses Weir Gulch on grade and would normallY. be forced t~ intercept run- off from Weir Gulch to the total capacLty of the dLtch. Barn~~ Lake, located at the intersection of 6th Avenue and F7deral Slvd., is the next major lake on the.Weir Gulch channel. ThLS lake is a recreational facility included Ln the Barnum Park complex. The lake has extreme legal and drainage implications as it creates a cross basin diversion during major storms. Reference to the 1937 quadrangle indicates that the historic location of 6th Avenue.across the Barnum Lake area was at the alignment of 5th Avenue. Dur7ng the construction of U. S. Highway 6 Freeway, 6th Avenue was realLgned to a straight course crossing the gulch in such a manner that the l~1 point ig at the intersection of 6th Avpnup ancl Fpd~T~1 Blvd. rather than directly over the gulch. Two S'x6' box culverts were installed under the 6th Avenue Freeway. These culverts are capable of passing 900 to 1,000 cu. ft. per se70nd prior to overt?pping of the 6th Avenue and Federal alvd. intersectLon. When overtoppLng occurs, flow will continue easterly along 6th Avenue and into the heavy com- mercial industrial area located adjacent to 6th Avenue. Such hLgh value concerns as the Sears Roebuck Warehouse, Showcase Restraurant and _13_