Laserfiche WebLink
<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />I' <br />17 <br />L <br /> <br />TABLE 2 <br />YAMPA RIVER HYDROLOGIC ANALYSIS POINTS <br />HYDROLOGIC <br />POINT LOCATION DRAINAGE <br />AREA (D.A.) D.A. <br />SOURCE <br />YO ABOVE FORTIFICATION CREEK 1492 miZ a <br />Y1 AT CRAIG GAGE (BELOW FORTIFICATION CR) 1750 mil a <br />Y2 BELOW WILLIAMS FORK 2241 miZ b <br />Y3 BELOW MILK CR 2529 miZ c <br />Y4 AT MAYBELL GAGE (BELOW LAY CREEK) 3410 miZ a <br />Y5 BELOW SPRING CR 3520 miZ c <br />Y6 ABOVE LITTLE SNAKE R 3796 miZ c <br />Y7 BELOW LITTLE SNAKE R 7606 miZ * b <br />Y8 DEERLODGE PARK GAGE 7660 miZ a <br />Sources of Drainage Areas <br />a. Determined from published information and USGS gage values <br />b. Determined from tributary USGS gage information combined with planimetering <br />c. Determined from planimetering <br />* The drainage area for the Little Snake gage location is at a point 9 miles upstream from the confluence with the Yampa <br />River. An additional 80 mil were measured between the gage location and the confluence. <br />Only one problem was encountered during the drainage area determinations. The drainage area <br />published by FEMA for the downstream limit of the study for the Craig Colorado area (2150 miZ) <br />was found to differ significantly from the value at the USGS gage location (1750 miZ). After a <br />careful review, including planimetering upstream of Craig to the Steamboat Springs gage and <br />downstream to the Maybell gage, the value at the gage location was selected as the most accurate.. <br />It is not clear what the source of the FEMA drainage area was, but it was assumed to be in error. <br />Figure 4 shows the study reach and each of the hydrologic analysis points listed in Table 2. <br />1 2.5 Flood Characteristics <br /> <br /> <br /> <br /> <br />Major flooding in the Yampa River basin has been primarily the result of rapid snowmelt <br />beginning as early as late April. Snowmelt flooding can continue into early July. Flooding can <br />also occur from rainfall on snowmelt and from ice jams in late winter or early spring. Due to <br />the small areal extent and limited duration of thunderstorms, they do not typically constitute a <br />flood threat on streams as large as the Yampa River. They do, however, pose a problem for <br />some of the smaller tributaries in the basin. <br />7