Laserfiche WebLink
<br />channel geometry, and measuring the stream discharge. Appendix B contains copies of field <br />data collected for this proposed segment. <br /> <br />. <br /> <br />Biological Flow Recommendation <br /> <br />The CWCB staff relied upon the biological expertise of the cooperating agencies to interpret <br />output from the R2Cross data collected to develop the initial, biologic instream flow <br />recommendation. This initial recommendation is designed to address the unique biologic <br />requirements of each stream without regard to water availability. Three instream flow hydraulic <br />parameters, average depth, percent wetted perimeter, and average velocity, are used to develop <br />biologic instream flow recommendations. The CDOW has determined that maintaining these <br />three hydraulic parameters at adequate levels across riffle habitat types, aquatic habitat in pools <br />and runs will also be maintained for most life stages of fish and aquatic invertebrates (Nehring <br />1979; Espegren 1996). <br /> <br />For this segment of stream, three data sets were collected with the results shown in Table 1 <br />below. Table 1 shows who collected the data (Party), the date the data was collected (Date), the <br />measured discharge at the time of the survey (Q), the accuracy range of the predicted flows <br />based on Manning Equation (240% and 40% of Q), the summer flow recommendation based on <br />meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 <br />hydraulic criteria. <br /> <br />Table 1: Data <br />Part <br />BLM <br /> <br />Date <br />7/19/95 <br /> <br />Q <br />2.81 <br /> <br />250%-40% <br />7.0-1.1 <br /> <br />Summer <br />4.25 <br /> <br /> <br />Winter 2/3 <br />1.6 <br /> <br />. <br /> <br />BLM = Bureau of Land Management DOW = Division of Wildlife <br />(1) Predicted flow outside of the accuracy range of Manning's Equation. ? = Criteria never met in R2CROSS Staging Table. <br /> <br />Biologic Flow Recommendation <br />The summer flow recommendation, which met 3 of 3 criteria and is within the accuracy range of <br />the R2CROSS model is 4.25 cfs (See Table 1). The winter flow recommendation which meets 2 <br />of 3 criteria and is within the accuracy range of the R2CROSS model is 1.6 cfs (See Table 1). <br /> <br />Hydrologic Data <br /> <br />After receiving the cooperating agency's biologic recommendation, the CWCB staff conducted <br />an evaluation of the stream hydrology to determine if water was physically available for an <br />instream flow appropriation. There are no currently operated or historically operated <br />streamflow gages for this reach. The closest gage CWCB staff found was the gage located on <br />Beaver Creek 5 miles west of the Specie Creek drainage. The hydro graph was derived from data <br />collected by the USGS stream gage for Beaver Creek near Norwood, CO (ID #09172000), which <br />has a drainage area of 40.6 square miles. The drainage area downstream of the Hughes Ditch is <br />approximately 8.9 square miles. Staff used a basin apportionment method to estimate stream <br />flows below the Hughes Ditch for Specie Creek (See Gage Summary in Appendix C). The <br />period of record for this gage was 1941 to 1981, the period of record used by staff in their <br />analysis was 1941 - 1981, or 34 years of record. Table 2 below displays the estimated flow of <br />Specie Creek downstream of the Hughes Ditch, in terms of a percentage of exceedence. <br /> <br />. <br /> <br />- 4 - <br />