Laserfiche WebLink
<br />Development of Estimated Daily Flows - Yampa River at Maybell <br /> <br />historical climatic data for estimation of evapotranspiration; types of crops grown in the basin; <br />diversions of irrigation ditches; evaporation rates; dates and patterns of first-fill of reservoirs; <br />and reservoir operations of consequence. <br /> <br />Related documents obtained and reviewed included: annual reports of the Division 6 <br />Engineer; irrigated acreage from the Consumptive Uses and Losses Reports prepared by the <br />Bureau of Reclamation; the recent water availability study done for the Colorado Water <br />Conservation Board; and reports of the Colorado Department of Agriculture and Bureau of <br />Census. The work also relied on information developed through numerous conversations with <br />the Division 6 Engineer and other water managers in the basin. <br /> <br />Definition of Study Period <br /> <br />The term "study period" here refers to the historical period of time over which daily <br />flow data sets were developed. While it is desirable to have as long study period as possible. <br />constraints imposed by the availability of both historical and modeled data sets limited it to an <br />interval from approximately 1950 to the present. Gaged Maybell flows were examined to <br />determine precisely which starting and ending years in this general time period should be used <br />to insure that all included dry spells are contained entirely within the study period. The study <br />period was then defined as extending from October I, 1949 to September 30, 1982 (water <br />years 1950-1982) <br /> <br />Daily Municipal Depletions <br /> <br />Daily municipal depletions were estimated by first establishing statistical relationships <br />between recent annual historical records of diversions and wastewater flows at the <br />municipalities, and recent population data. The relationships were then used to estimate annual <br />depletions from 1950 to 1982 using population data over the study period. The depletions were <br />then disaggregated into monthly values using an average monthly pattern observed in recent <br />historical records, and the monthly depletion computed as the difference between monthly <br />diversions and wastewater return flows. Finally, the monthly depletions were disaggregated <br />into daily values using a spline interpolation scheme that preserved the total flow volume in <br />each month. Daily municipal depletions were estimated for the municipalities of Steamboat <br />Springs and Mt. Werner, Hayden, and Craig. <br /> <br />Steamboat Springs and Mt. Werner Water and Sanitation District <br /> <br />Total annual depletion data between 1985 and 1991 were related to population over the <br />same period. The annual depletions were obtained from the aggregated monthly depletions in <br />recent years. Monthly depletions were computed as diversions minus wastewater effluent. The <br />diversion data were obtained from the Fish Creek Reservoir Expansion EIS Water Resources <br />Technical Report (ACZ, Inc., 1992), which provides the monthly water usage by the City of <br />Steamboat and the Mt. Werner district. Data on total annual wastewater flow from the <br />treannent plant over the 1985 through 1991 period were obtained from the City and were <br />reduced by 5.39 % to remove contributions by Steamboat II. Sleepy Bear and Ski Town (since <br />diversion data were not available for these small domestic systems). This data was then also <br />related to population data over the study period. <br /> <br />2 <br />