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<br />SECflOl'\" V <br /> <br />During the course of this study, numerous components of the existing storm drainage system <br />wcre found to be inadequate. Some ofthcse inadequacics are due to recalculated peak <br />flows determined through the llse of new dcsign criteria and development within the basins. <br />Other prohlems could be attributed to inadequate maintenancc an(! previous polley. These <br />problems, compounded by the increased flow projections, add to the inadcquacy of the <br />existing syStem. Thc following sections of this report discuss those inadequacies and offer <br />recommended solutions. The preliminary dcsigns completed in this Drainage Master Plan <br />for recommended improvements to drainage facilities have been based on guidelines within <br />the Teller County Drainage Criteria Manual ("Areawide Urban Runoff Control Manual" <br />prepared for the Pikes Peak Area Council of Governments by Gilbert, Meyer and Sam.'>, <br />Inc., 1980). <br /> <br />HYDRAlUCS <br /> <br />There are currently many drainage facilities within the corporate limits of Cripple Creek. <br />They are, for the most part, culverts and short sections of drainage conduit used to transport <br />drainage flows under major facilities sueh as streets, highways and railroads. As such. they <br />were installed to solve specific and isolated drainage problems. Most facilities were <br />instaUed many years ago and were not designed to account for infreq uentpeakflowrates. <br /> <br />Existing drainage facilities were evaluated on-site to determine dimensions and physieal <br />condition for incorporation into this Drainage Master Plan. Exbibit 2, "Drainage Structures", <br />and Exhibit 3, "Bennett Avenue Storm Sewer System," indicate tbe location of existing <br />drainage structures. The information contained in Appendix C incorporates tbe results of <br />a field reconnaissaneeeffort into locating and determining sizes a ndconditionsofexisting <br />facilities. Table 5 in Appendix B, "Existing Drainage Structure Evaluation", indicates the <br />estimated capacity of each existing structure and the required design inflo wrate. <br /> <br />During preparation of the Flood Plain Management Study by tbe Soil Conservation Service, <br />a flood plain map for the City of Cripple Creek will be prepared. In negotiation, with the <br />Soil Conservation Service and the Colorado Water Conservation Board, it has been agreed <br />to prepare the flood plain mapping to incluue any structure improvcmcnt> maue during the <br />calendar year, 1992. An additional analysis will also be performed whkh will map the flood <br />plain ha,ed on all recommended improvements. This procedure will allow a comparison <br />of the existing flood plain versus the flood plain limits once all recommended improvements <br />are completed. <br /> <br />To determine the adequacy of the existing facilitie>, and to develop a new system which will <br />conform with this master plan, the design capacity of each existing structure was calculated. <br />Hydraulic Engineering Circular No.5, "Hydraulic Charts for the Selection of Highway <br />Culverts", published by the U.S. Departmcnt of Commeree. Bureau of Public Roads was <br />utilized to estimate design capacity of the existing struclllres. Drainagepatternswcrealso <br />studied to determine the suitability of existing drainage facilities and the need for new <br />facilitie,. AI the time of detailed design of any improvements, final design anal}'sis may <br />resllltindcterminingthathydrauliceonditionsareslightlydifferentthen represented here. <br />The city should plan 10 take that into account when reviewing and approving final <br />construcllon plans. <br /> <br />V-I <br /> <br />V-2 <br />