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Surface Water <br />The Yoast Mine drains to Sage Creek on the west side and to Grassy Creek on the east side. <br />Sage Creek and Grassy Creek are perennial tributaries to the Yampa River. Annand Draw and <br />Scotchman's Gulch are intermittent drainages which drain from the northern side of the permit <br />area into Grassy Creek. The Yampa River then flows to the Green River and eventually to the <br />Colorado River. <br />Sage Creek <br />Sage Creek is a perennial stream to the west of the permit area. Flows upstream from the permit <br />area range from an average 0.7 cubic feet per second (cfs) in the spring to near 0 in late summer <br />and fall. Approximately two miles downstream from the permit area, average flows of 1.5, 0.09, <br />and 0.04 cfs were observed during baseline data collection in the spring, summer, and fall <br />respectively. <br />Water quality in Sage Creek varies from upstream to downstream. Baseline data indicate a <br />predominantly CaMgHCO3 water type upstream from the permit area. Total dissolved solids <br />(TDS) typically ranged from 296 to 510 mg/1 at high and low flows, respectively. A <br />CaMgSO4HCO3 water type predominated downstream from the permit area, and TDS typically <br />ranged from 526 to 695 mg/1 at high and low flows, respectively. <br />Most of the flow in Sage Creek is diverted out of the stream for irrigation purposes prior to <br />reaching the site where downstream baseline data was collected. Sage Creek water is also <br />utilized for livestock watering. <br />Grassy Creek <br />Grassy Creek is a perennial stream to the east of the permit area. Flow in Grassy Creek upstream <br />from the permit area was perennial during baseline data collection. Mean flow rates in the <br />spring, summer, and fall were 0.91, 0.10, and 0.06 cfs respectively. A CaMgSO4HCO3 water <br />type predominated upstream from the permit area. TDS ranges from 680 to 853 mg/1 at high and <br />low flows, respectively. <br />Permit Area <br />Intermittent flows from the northern side of the permit area drain through Annand Draw into <br />Scotchman's Gulch and then into Grassy Creek. Spring flows in Annand Draw are <br />predominantly from the melting of snowpack. Late spring to early summer flows are a <br />combination of bank storage, runoff from precipitation events over saturated or frozen ground, or <br />perched spring flow recharged by snowmelt. The remainder of the year, the channel exhibits <br />ephemeral flow characteristics. The mean flow rate in the spring is .056 cfs, and .02 cfs in the <br />summer. <br />Within the permit area, there are five primary drainages, four of which are ephemeral. The <br />drainage channels have been identified as Annand Draw, 011 Draw, Y1 Draw, Y2 Draw, and Y3 <br />N <br />