Laserfiche WebLink
<br />South Barton Creek <br />Middle Barton Creek <br />North Barton Creek <br />Gold Run Gulch <br />French Creek <br />Illinois Gulch <br /> <br />3.5 sq. mi. <br />1.8 sq. mi. <br />2 . 6 sq. mi. <br />3 . 6 sq. mi. <br />11 . 1 sq. mi. <br />3.2 sq. mi. <br /> <br />DRJ\F1 <br /> <br />The Master Plan Boundary borders the south side of the Swan River <br />in several locations, but the majority of the watershed lies <br />outside of the MPA. Only its tributary, Gold Run Gulch, was <br />included for analysis in this report. <br /> <br />REGIONAL FREOUENCY ANALYSIS <br /> <br />The regional frequency analysis was conducted to develop peak <br />discharges for the Blue River. The purpose of this analysis was <br />to determine if the values from the previous studies were still <br />representative of peak discharges in the Blue River basin in light <br />of flow data available since those studies were conducted. In <br />addition, it was felt that for lower return period flows on the <br />major tributaries these peaks would be more representative of <br />events dominated by snowmelt, than the HEC-l results obtained by <br />modelling rainfall-runoff characteristics. <br /> <br />Methodoloov <br /> <br />A regional frequency analysis consists of determining the frequency <br />curve for peak discharges at a number of stations with similar <br />characteristics. Relationships for specific return periods using <br />the various station peaks and watershed characteristics are <br />determined by developing regressions for peak discharge based on <br />the basin characteristics. For this study, the methodology <br />presented in "Guidelines for Determining Flood Flow Frequency - <br />Bulletin #17B" (United States Water Resources Council, 1981) was <br />used to define frequency curves for annual peak discharges measured <br />at a number of united States Geological Survey (USGS) gaging <br />stations throughout the Blue River Basin and adjacent watersheds. <br />This procedure was accomplished through the implementation of the <br />computer program "FFAN - Flood Frequency Analysis" (Hydrasoft, <br />1985) which uses the methodology from the previous publication to <br />develop frequency curves. After the frequency analysis was <br />conducted, the equation to determine specific return period <br />discharges was developed by regressing the peak discharges for a <br />specific return period against the watershed characteristics <br />assembled with each station's discharge. In this case, area was <br />used as the representation watershed characteristic. <br /> <br />Data <br /> <br />5 <br />