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<br />In 1988, Hydrodynamics wrote a master drainage study for Central City and included <br />peak flow estimates from the CWCB report. A significant result of this report was a <br />recommendation to construct a detection basin above Central City. <br /> <br />The current Flood Insurance Study for Central City is based on hydrology studies by <br />Rocky Mountain Consultants, Inc. in 1991 and 1992. The FEMA peak flow for Central <br />City at the downstream city limit is 969 cfs, and includes the effects of the Dorothy <br />Lee reservoir. <br /> <br />A flood mitigation and water quality improvement project was presented in 1995 by <br />Futura for a joint effort between the City of Black Hawk and the Black Hawk <br />Gaming/Jacobs Entertainment Joint Venture (BHJ). The intent of the project was to <br />construct a buried flume to carry a majority of the flow in North Clear Creek, a pipeline <br />to separate contaminated flow from EPA superfund sites, and to allow some flows to <br />remain in an NCC landscaped open channel. The OA&A flow estimate was selected <br />for the design, although the OA&A numbers do not reflect the presence of the Dorothy <br />Lee Reservoir. Two design flows were listed in the report, however, 2670 cfs the <br />OA&A flow, and 2,400 cfs which reflects the 270 cfs peak flow reduction from the <br />reservoir. <br /> <br />C. Summary of Available Flow and Climate Data <br /> <br />The calculated flow estimates from the studies in Table 1 were not calibrated with <br />actual stream flows because there is a dearth of information on flow rates for Gregory <br />Gulch and North Clear Creek. The only climatological or hydrological information <br />available for this area consists of the following. <br /> <br />1. Four years of stream flow records, 1951 - 1955, for North Clear Creek. The <br />station was located four and a half miles southeast of Black Hawk. No other <br />gages are located on North Clear Creek. The longest records for Clear Creek <br />are from Lawson, drainage area 147 sq m, Golden, drainage area 399 sq m, and <br />the mouth of Clear Creek, drainage area 575 sq m. <br /> <br />2. There are intermittent records available from 1956 to 1977 for a <br />precipitation station at Central City. The station was not in operation during the <br />three major floods in July 1975. The two closest precipitation gages are Idaho <br />Springs and Nederland. <br /> <br />3. Newspaper accounts researched by CWCS. <br /> <br />4. Oral testimony from residents. <br /> <br />5. Oral testimony from state or city maintenance personnel. <br /> <br />9 <br />