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• li~ 13 A number of separate drainages have their headwaters in the mine environ- mental study area. Sylvester Gulch and Lone Pine Gulch are ephemeral streams which drain the northern portion of the arAa. They flow directly into the North Fork. There are five tributaries which drain into the main flow of Minnesota Creek. Characteristics of the drainages are given in Table 1. No flow was observed in Lone Pine Gulch for a period of years; thus, it was omitted from the study. ~,. Sylvester Gulch is an ephemeral stream and has a~drainage area of 4.25 square miles. It .is important ~,o•'~MOte that the major portion of the surface facilities will be located near this drainage in the valley adjacent to the North Fork. As indicated on Table.cl;'~the hydrologic yield of Sylvester GuZCh is Zow compared to the other watersheds. This is"~ue to the fact that it drains a lower elevation area with mo~~gentle slopes. Horse Creek, South Prong, Lick Creek,,~Dry Fork, and East Fork drain into Minnesota Creek. Their sZopes,.a n~'generally more steep and the watersheds are at higher elevations than those tributary to the North Fork. Based upon . streamflows measured in water year°1978, the water yields from these drainages are nearly an order of magnitude greater,than that of Sylvester Gulch. t..pM . i There are numerous springs Iotrated throughout the""site. Measurements indicate that spring flows generally decrease fromja high in the early summer to a low point in the fall. A numbezT of the springs dry`up in the winter, indicating that their source is most likely a small localized ground-water table . •l,,qr• • "°° ~ : •rrr . ;. Two reservoirs are located within~the'study area. ,~Kinnesota Reservoir is located on Dry Fork. It has a decreed capacity of 1,285 acre-feet. The actual capacity may be closer to_500 ehre-feet, however. Beaver Reservoir is located on the East Fork of Minnesota Creek•and'has an absolute decreed capacity of 1,620 acre-feet and awCpndit~onal decree of 552 acre-feet. Both reservoirs store water for ir.ri'gation purposes and:~ar~ filled during spring runoff. They are usual'Iy drained by ~ate'AUgust or early September. .. ~~ Water quality parameters for the North Fork are given in Table 2. As indicated, waters in the North Fork are a calCiuin bicarbonate type. There are moderate levels of sulfate. Salinity 'averages Ie~ss than 100 mg/1. Water quality data has been collected at severalysit~s throughout the en vironmentaZ study area. The data indicate that'"those waters are aZso`the calcium bicarbonate type with relatively low total disso,ZVed"solids concentrations. There are a total of 13 decreed water rights on or near the base area. The applicant has determined that~an•ai4ditional 29 downstream rights might be affected by the project. The majority of springs that might be impaired are located above the "F" seam outcYOp. Water rights on Minnesota Creek will be impaired to the level that`~~flow is decreased due to mining activities. .~~trta ,.~a'- : +~' ~~ ~ ~e '~n~.;~~" M~ ~ ~~.~ r ''Y .1.:a~M•