Laserfiche WebLink
Precipitation and Storm Type. The precipitation amounts at the Yoast Mlne permit area for <br />the 10-yea r,25-year, and 100-year storms were obtained from NOAH Precipitation <br />Frequency Atlas Precipitation - Frequency Atlas of the Western States - Volume II - <br />Colorado, 1973. A standard SCS Type II storm xas utilized for each analysis. <br />Unit Hydrograph antl Surface Condition. The SEDCAD+ computer program provides three unit <br />hydrog raph shapes to choose from Sn determining the runoff characte ristlca of a watershed. <br />Time of Content ra tlon. The time of concentration, tc, is defined as the time required for <br />water to flow from the hydraulically most remote point Sn the watershed to the watershed <br />outlet. <br />The time of concentration for Pond 010 was calculated using the SEDCAD+ computer program. <br />The program determines overland flow to a pond structure by utilizing the Seven SCS Upland <br />Curves which yield velocity as a function of slope and land use (Ba rfleld et al., 1983). <br />Listed below is a summary of the time of concentration for the subwatersheds. Please <br />refec to the SEDCAD+ outputs for the calculated time of content ration for the <br />subwatersheds. <br />TABLE 13-3-3 <br />Time of Concentration <br />Pond 010 <br />wa tetshed <br />No. Flow Path <br />No. Ho r. Dl st. <br />Ift.) Vert. Dist. <br />(ft.) Land Use <br />Category TC <br />(hr.) <br />2 4a 6080 535 3 0.8]3 <br />2 4b 1440 320 1 0.335 <br />3 9a 1860 180 7 O.OB3 <br />3 9b 640 80 6 0.034 <br />3 9c 860 68 3 0.121 <br />4 8 360 55 7 0.013 <br />4 ea 480 115 3 0.039 <br />5 7 920 155 7 0.031 <br />5 7a 720 55 7 0.036 <br />5 7b 760 315 3 0.047 <br />6 3 840 35 7 0.057 <br />6 3a 540 145 3 0.014 <br />7 2 600 35 7 0.034 <br />7 2a 640 70 3 0.077 <br />`J <br />13-3-4 Revised 09/08/95 <br />