9468 - Laserfiche WebLink

Home Browse Search

2.3 Basin Characteristics ' The White River is a tributary to the Green River, which is in turn a tributary to the Colorado River. The White River joins the Green River downstream of the study reach in Utah. The White River has its headwaters in the Flat Tops Wilderness to the east and south and in the White ' River Plateau to the south and west. The watershed area at the downstream limit of the study at the Utah stateline is 3552 square miles. The elevation within the watershed ranges from above 11,500 feet above Mean Sea Level at the headwaters to 5070 feet at the downstream limit of the study. The average slope within the study reach is approximately 12 feet per mile with a maximum of 20 feet per mile in the upper reach and a minimum of 8 feet per mile at the Utah border. The climate within the White River basin is classified as semi-arid and is characterized by low ' precipitation, large daily temperature range, low humidity, and frequent wind. The primary sources of moisture are from air masses originating in the Pacific Ocean from October through April, and airmasses from the Gulf of Mexico during the late spring and summer. Normal annual precipitation ranges from approximately 10 inches near Rangely to approximately 16 inches near Meeker (18 miles upstream of Rio Blanco Lake). Most of the annual precipitation (60 percent) occurs as snow from October to April. Rainfall can occur as convective-type thunderstorms ' during the late spring and summer months generally over the lower elevations of the basin. The White River basin, from its headwaters to the Utah stateline, is shown in Figure 3. ' 2.4 Summary of Drainage Areas The drainage areas for selected hydrologic points were determined through planimetering. The ' results of the planimetering were then compared to known drainage area values at USGS gage locations and at published flood study locations. The drainage areas at these selected hydrologic points are shown in Table 2.