Laserfiche WebLink
<br /> <br />• <br />• <br />TABLE 1 <br />MEASURED AND ESTIMATED RALSTON CREEK WATERSHED AREA CHARACTERISTICS <br />Drainage Area: <br />Maximum Watershed Relief: <br />Approximate Main Channel Length: <br />Approximate Main Channel Slope: <br />Approximate Watershed Land Slope <br />Hydrologic Soil Groups: <br />Estimated Runoff Curve Number: <br />38.3 square miles <br />3,450 feet <br />14.8 miles <br />4.4 percent <br />38.0 percent <br />1 2%A; 35%B; 6%C; 57%D <br />2,3 63 for AMC-II condition; <br />81 for AMC-III condition <br />I As defined by Soil Conservation Service National Engineering <br />Handbook, Section 4, Hydrology, Chapter 710, 15 and 21. <br />2 A runoff curve number represents the relative value of the watershed <br />hydrologic soil-cover complex as a direct runoff producer. A greater <br />amount of direct runoff is expected from a storm fora watershed with <br />a higher runoff curve number than from one with a lower number. <br />3 o AMC-II. -The average case for annual floods, that is, an average of <br />the conditions which have preceded the occurrence of the maximum <br />annual flood on numerous watersheds. <br />o AMC-III.-When heavy rainfall or light rainfall and low temperatures <br />have occurred during the 5 days previous to the given storm. <br />-11- <br />