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this analysis, the flood peak estimates were determined from a regional analysis of peak-flow data from stream-gaging stations in the area. Peak discharges for the 10-, 2-, 1- and 0.2-percent annual chance floods for Chicken Creek were computed using regionalized basin parameters deternuned by the COE for the Mancos River. ~omparative hydrologic calculations were also made for the Chicken Creek basin using the Manual for Estimating Flood Characteristics of Natural-Flow Streams in Colorado as well as unit area '~ discharges. Peak discharge-drainage area relationships for the City of Cortez Studies ~ (Carpenter Wash, Denny Lake, Glade Draw, Industrial Wash, Lower Cornett Draw, South Central, West South Central, and Walmart Tributary), Chicken Creek, Dolores River, West Dolores River, Lost Canyon Creek, and Mancos River are shown in Table 1. Table 1 - ~ummary Of Discharges Peak Discharges ( cubic feet per second) 10-Percent 2-Percent 1-Percent 0.2-Percent Drainage Area Annual Annual Annual Annual Flooding Source and Location (square miles) Chance Chance Chance Chance Carpenter Wash (City of Cortez) At North Broadway (Hwy 491) 7.34 -- -- 479 -- At Confluence with Lower 1.28 -- -- 337 Cornett Draw County Road 26 0.23 -- -- 102 Chicken Creek ~ At the Town of Mancos 22.3 490 800 950 1,370 Denny Lalce (City of Cortez) At Main Street (Hwy 160) 0.57 -- -- 425 -- Dolores River Below the Rico Gage 105 -- -- 2,290 -- Above Bear Creek Confluence 170 -- -- 5,490 -- Below Bear Creek Confluence 204 -- -- 6,470 -- ,. Above West Fork Confluence 278 3,700* 6,000* 7,516 20,000* Below West Fork Confluence 446 -- -- 11,300 -- At the Town of Dolores 504 -- -- 11,700 -- Below Lost Canyon Creek 579 6 800* 11 500~ 12 300 36 000* Confluence , , , , Glade Draw (City of Cortez) Approx. 0.4 Miles Upstream of 0 51 -- -- 187 -- Confluence with McElmo Creek . At 7~' Street 0.17 -- -- 95 -- Industrial Wash (City of Cortez) At Confluence with Carpenter 5.76 -- -- 425 -- Wash 11