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a <br />44 <br />to estimatd the effect of the mine discharges is used. Unfortunately, there <br />~ is no effective means of directly measuring the quantity of water passing • <br />through the waste dump and it is necessary to estimate the deep percolation <br />through the use of water balance orocedures. <br />This analysis of hydrologic balance is restricted to the refuse dump . <br />at the Allen Mine. A map of the dump is presented in Figure 13, The <br />water balance is analyzed on an average annual basis using long term mean <br />climatic data where available. The overall hydrologic system is broken <br />down into two subsystems, the subsurface water budget and the surface water <br />budget. The two subsystems are linked by infiltration (see Mc:lhcrter, 1480; <br />for basic details). <br />Climatic Summary - Precipitation, temperature, and solar radiation data <br />~ utilized in the computations are presented in Table 9. Mean temperature <br />and precipitation data based on 20 years of record are available at Trini- <br />i dad approximately 25 miles east of the Allen Mine and at North Lake approxi- <br />mately five miles west of the Allen Mine. Elevations at these two sites <br />~ are 6030 feet and 8800 feet, respectively, while the elevation of the refuse <br />pile is approximately 7470 feet. The means for these two locations show <br />C substantial variation, probably due to elevation differences, Therefore, . <br />the mean precipitation and temperature data presented in Table 9 were ob- <br />tained by interpolating on elevation between data for Trinidad and North <br />Lake. (The means far Trinidad and 'forth Lake are presented in Appendix F.) <br />Solar radiation data is available at only a few locations in Colorado, all <br />of which are some distance north of the mine site. For this reason the amount <br />of, solar radiation was calculated usinq a method presented by Jensen (1913). <br />Details and comparative data are presented in Appendix F. <br />Potential Evaporation - The amount of water lost to the atmosphere was <br />calculated by dividing the year into a winter season (Nov. through I.1ar.) <br />and a growing season (Apr. through Oct.). 'linter period losses result from <br />sublimation and evaporation and were estimated using the following equation <br />(Wymore, 1974). <br />Ew = Kc (0.0067 + 0.05) Rs C <br />in which Ew represents evaporation losses from snow pack (inches), T <br />represents mean monthly temperature (°F) Rs is the solar radiation (lv/d) <br />