WSP06951 - Laserfiche WebLink

Home Browse Search

2 percent greater than the average of 441 mg/L. However, the measured discharge of 84 ftl/s was about 40 percent greater than the average discharge from the station of 60 ft3/s. ~ ~ 00 ~ The adjusted dissolved-solids concentration for the Roaring Fork River near Glenwood Springs (site 25) was about 500 mg/L. The adjusted base-flow salt load for the Roaring Fork River was 183,000 ton/yr, and the adjusted average discharge was about 370 ftl/s (fig. 7). The Roaring Fork River downstream from the confluence with Woody Creek (site 16) increased discharge by about 265 ftl/s and increased salt load by about 150,000 ton/yr. Measured tributary inflow along this reach accounts for l46'ftl/s and 55,400 ton/yr, respectively. The remainder, 119 ft3/s and 94,900 ton/yr, is estimated to be contributed by unmeasured tributary inflow, which is small, and by direct ground-water discharge into this reach of the Roaring Fork River. Main-stem Colorado River upper headwaters This subbasin includes the drainage area of the main-stem Colorado River and tributaries upstream from G1enwood Springs, exclusive of the Blue River, Eagle River, and Roaring Fork River drainages. Most of the rocks exposed in the headwaters region of the Colorado River, Fraser River and Williams Forks are igneous and metamorphic. Tertiary sandstones and semi-consolidated conglomerate in hydrogeologic unit 3 (table 1) and local areas of extrusive igneous rocks underlie the north side of the subbasin between Granby, Colo., and Kremmling, Colo. Upper Cretaceous shales in hydrogeologic unit 7, rocks in hydrogeologic unit 3 (table 1), and local areas of extrusive igneous rocks crop out in the Muddy Creek drainage north of Kremmling. Some igneous and metamorphic rocks, some Permian rocks, and the rocks in hydrogeologic units 7 and 3 crop out in the Piney River and Sheephorn Creek drainages south of the Colorado River. Principally igneous and metamorphic rocks underlie the drainages north of the Colorado River between Kremmling and State Bridge, Colo. The remainder of the subbasin north of the Colorado River between State Bridge and Glenwood Springs is underlain mostly by undifferentiated Cambrian, Ordovician, Devonian, and Mississippian rocks; the Maroon ,Forma- tion; the Eag1e.Valley Evaporite of'Pennsylvanian and Permian age, and other related Pennsylvanian and Permian formations; the Dakota Sandstone; the Mancos Shale; and landslide deposits of Quaternary age. The headwaters of the main stem of the Colorado River are located above Lake Granby. The high mountainous terrain that forms the headwaters region of the Colorado River produces large quantities of good quality water. The discharge of the Colorado River at Hot Sulphur Springs, Colo. (site 29), averages about 130,000 acre-ft/yr, and the mean annual dissolved-solids concentration is 80 mg/L. This discharge is about 200 acre-ft/mi2. Most of the tributaries entering the Colorado River from the north between Kremmling and Glenwood Springs, Colo., originate in the White River Plateau. They have a mean annual dissolved-solids concentration of about 200 mg/L. The Colorado River just below Glenwood Springs has an average annual discharge of close to 2.6 million acre-ft and a mean annual dissolved-solids concentration of about 400 mg/L. 26