Laserfiche WebLink
<br />SECTION III. AUGMENTATION POTENTIAL <br /> <br />. <br /> <br />Most of the flow of the Colorado River originates from seasonal <br />snowpack in the alpine and subalpine watersheds where winter <br />precipitation amounts are high and evapotranspiration losses are <br />low due to colder temperatures. The contribution to the total <br />Basin runoff by summer precipitation is small in comparison with <br />winter snowfall. The important runoff-producing snowpack water- <br />sheds cover only a small part of the Colorado River Basin. Since <br />they are on mountain barriers where winter orographic clouds occur, <br />applying weather modification over these areas to significantly <br />augment the Colorado River becomes a reasonable objective. Total <br />regional augmentation benefits, including concurrent increases in <br />water-short areas adjacent to the Colorado River Basin, can be an <br />important factor in the effort to enhance regional and intra-state <br />water supplies. <br /> <br />The Upper Colorado River watershed above Lee Ferry, the2dividing <br />point betwezn the Upper and Lower Basins, is 283 600 km <br />(109,500 mi ) with an overall average runoff of approximately <br />58 mm (2.3 in.) 8/ Five major runoff-producing areas of the <br />Upper Colorado Rive2: Basin have2been identified (fig. 3 ), and <br />include a 36 800 km (14,200 mi ) area. ~/ About 75 percent of <br />the total Upper Colorado River Basin water supply comes from these <br />five high yield areas that represent 13 percent of the Upper Basin <br />area. The estimated average runoff per square kilometer (mile) from these <br />areas is about 330 mm (13 in.) of water. Another2lO percent20f <br />the runoff is produced in an additional 24 600 km (9,500 mi ) that <br />yield 25 to 254 rom (1 to 10 in.) of runoff, with an average yield <br />of 76 rom (3 in.). Nearly half of these lower yield areas <br />immediately surround the five high yield areas. <br /> <br />The high yield runoff areas are generally above the 2743- to <br />2896-m (9,000- to 9,500-ft) elevation. These and the adjoining <br />lower yield areas are the primary locations for precipitation <br />management in the Upper Basin. <br /> <br />" <br /> <br />111-1 <br />