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13 CLIMATE <br />The permit area is located at 9,800 feet elevation. Natural Resources Conservation Service <br />(NRCS) Technical Release No 55 is a tool for estimating peak runoff and volumes for watersheds <br />and drainage basins. It is an improvement of some of the original work that was done in the <br />1960's and 1970's that culminated in the Colorado Water Conservation Board Technical Manual <br />No. 1, published in 1976, at that time, being the bible for estimating storm water runoff and <br />flows for this area. The release provides a technical improvement in ease of manipulating data, <br />but produces no improvement in accuracy for flows, especially over small areas. Per National <br />Oceanic and Atmospheric Administration (NOAA) Atlas 14, the 24 -hour precipitation for the 10- <br />year event is 2.5 inches and 4.2 for the 100 -year event. <br />(b)(ii) <br />The predominant wind direction is westerly and the open areas are typically breezy. During the <br />summer months, gross southwesterly winds tend to bring in warmer temperatures and <br />northwesterly winds tend to bring cooler temperatures. During winter, fronts can come from <br />any direction with precipitation occurring dependent on temperature variations and air <br />moisture on the edge of the front. The period of mid -July to mid - September is dominated by <br />the Bermuda high that typically sets up that time of year. Whether moisture is brought into <br />this mid - continent area depends on the location of the low and its strength. <br />(b)(iii) <br />The monthly mean monthly temperatures are shown in the Table below: <br />Average Temperatures for Cripple Creek, Colorado - (source NWS) <br />°F Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec <br />Average <br />33 36 42 49 59 70 75 72 65 55 42 33 <br />high <br />Average <br />13 15 21 26 35 44 49 48 40 31 21 12 <br />low <br />(b)(iv) <br />A review of the average relative humidity for the area shows it to be generally less than 20 <br />percent. As would be expected, evaporation rates were reviewed in the general Cripple Creek <br />District and vicinity and were found to be quite high. The average evaporation rate for the <br />Front Range area is on the order of 36 to 40 inches. This amount of evaporation greatly <br />exceeds the annual rainfall indicating that, if the assumption were made that the entire <br />precipitation captured in any detention areas were not recycled nor allowed to infiltrate, the <br />evaporation would greatly exceed the total precipitation by at least a factor of three. <br />8 <br />