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The normal annual precipitation in the Mancos area is approximately 16 inches. FrCtllJuly to October, approximately 40% of the normal annual precipitation results from rain, generally from thunderstorms. From December to April, the remaining 50% of the normal annual precipitation occurs as ,now. Winters in the study area are long and cold,withmean daily temperature, of approxi- mately 30oF, between the winter months of November to March. Summer, are short and hot with mean daily maximum temperatures greater that 90oF. flood waters can collect on the floodplain vegetation and further impede and alter flood flow pattern, in these areas. There are no existing or planned flOOd control structures in the study area, or upstream of the study area. which could reduce the pre,ent flOOd halard. However, the Corps of Engineers completed bank protection work alo~ the river banks at the sewage lagoons in OeceoOer, 1973. Study Reach Description Mancos River - The Mancos River study reach is centered about the Town of Mancos from the west end to the east end of town. The lower study limit is at a point southwest of the Ohio rtatch Companyyard,approximate lyD.Smiles west 0 f Spruce Street ~ The up pe r study 1i m; tis a t a po i nt nea r the i nte r_ section of Grand Avenue and Montezuma Street, on the east side of town. The lm::lexM<ip,Plate2,showstllestudylimitsandrMplimits. Cllicken Creek The Chicken Creek study reach begins at U.S. 160 and ex tenus upstream to a point near two private fishing ponds, west of S.H. 184, a~d approximately l.Smiles north of U.S. 150. The study reach is l.Smiles in iengch. Mapping liffi;tatlons 00 not permit the downstream st~dy limit to be shown on the flOOded areas map. The study limits and map limits are shown on the Index Map, Plate 2. The Mancos kiver channel meanders through the study reach, traversing approxi- mately1.7rr,ilesthrovgh the 1.6 mile reach of floodplain. The areas adjoining the Mancos River are very flat and are not fully developed, with the exception of the Town area, near Main Street. At Main Street, building walls and fJundatiJns,erveasthechanncloank. The Chicken Creek floodplain and areas along the study reach are currently undeveloped. However, plans are being made for future development in areas adjoining Chicken Creek. The lOO-year floodplain will be considered in finalizing those plans, to avoid tr.e placement of improved facili tie, in flood hazard areas. Through the study reach, four major road, cross the river. Onlythe!:rridge crossing at Spruce Street significantly affects flood flows within the flood- plain. The sewage lagoons near the downstream limit do not jm~act 100-year flood widths. OownstreamofMainSreet,nearfleSa Streetextended,a sewer line crosses the river. The pipe has been encased and stabilized by a gabion droDstructure. TnerearenomaJorbndgecrOSSlngs lnthe reach of the Chicken Cre ekstudy. Two driveway bridges cross the Creek but are insignificant to t~e floodplain. Th~ fishing ponds near tMe upstream limit encroach into the natural flOOdplain dt'ea but do not affect flood flows. r~a t ura lObs true t ions to fl ow, i nc 1u ding brush. vegeta t i on and f d 11 e n trees, exist pri~arily in the middle of the study area. These obstructions do not cause a threat to properties adjoini~ the creek. Other obstructions to flood flows through the study area are the brush and \'egetationalongandwithinthechannel. During periods of high water, floodplain vegetation tends to i:l1pede or slow flood flows. Debris carried by -9- -10-