Laserfiche WebLink
<br />..... <br />(7) <br />00 <br />...oJ. <br /> <br />The mean annual dissolved-solids concentration of the headwaters of the <br />Eagle River is about 100 mg/L. At its mouth, the Eagle River has nearly <br />triple that concentration, about 300 mg/L, and an average annual discharge of <br />about 400,000 acre-ft (420 acre-ft/mi2). <br /> <br />Five sampling sites were selected in this subbasin (figs. 3 and 6; <br />table 2). Dissolved-solids concentrations in the Eagle River at the upstream <br />sites were about 140 mg/L at Redcliff, Colo. (site 8), and 190 mg/L at Avon <br />(site 9). These concentrations are small and indicate the relative <br />insolubility of the metamorphic and carbonate rocks comprising much of the <br />drainage area upstream from the sampling points. Dissolved-solids <br />concentrations ranged from 494 to about 780 mg/L at the three sites downstream <br />from Avon (sites 10-12), reflecting the contribution from extensive exposures <br />of Eagle Valley Evaporite deposits in the drainage areas upstream from these <br />three sites. Soil disturbance caused by extensive ongoing development around <br />Avon also may be related to the larger salinity concentrations downstream. <br /> <br />A water-quality station is on the Eagle River upstream from Gypsum Creek <br />(site 11). The average dissolved-solids concentration in the Eagle River at <br />this site during December, January, and February of water years 1976-77 was <br />678 mg/L. The dissolved-solids concentration of the sample collected was <br />731 mg/L or about 8 percent larger. The discharge at this station is measured <br />below Gypsum Creek. The 2-year base-flow average was 183 ft3/s. The combined <br />discharge for Eagle River upstream from Gypsum (site 11) and Gypsum Creek near <br />the mouth (site 12) at the time the sample was collected was 198 ft3/s or <br />about 8 percent larger than the 2-year base-flow average. The Eagle River <br />subbasin discharged an estimated average base flow of 198 ft3/s and an annual <br />salt load of 135,000 tons (fig. 6). <br /> <br />8 <br /> <br />EXPLANATION <br /> <br />.,. 9 SAMPLING SITE AND NUMBER <br />(TABLE 2 AND FIGURE 31 <br /> <br />('5,6001 SALT LOAD. IN TONS PER YEAR <br /> <br />. <br />o <br />0: <br /> <br />115,6001 9 <br /> <br />" 10 Brush Creek <br />0, <br />LS (34,6001 <br /> <br />11 <br />(118.0001 12 Gypsum Creek <br />(16,BOOI <br /> <br />1135,0001 <br /> <br />Figure 6.--Drainage system and salt load: Eagle River subbasin. <br /> <br />23 <br />