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The region is characterized by a semi-arid steppe climatic regime with cold winters and mild to <br />cool summers. The prevailing wind is from the northwest (reversing at night due to southeasterly <br />upslope winds). Average annual precipitation is 16 inches and the growing season in the region <br />is approximately 94 days. Climatic information was collected from Xcel Energy's Hayden <br />Station power plant, one mile away, and the Seneca II-W Mine, six miles south of the Loadout. <br />Surface Water Hydrology <br />Surface water information is found in the following sections of the permit application: Tabs 7, <br />12, 13, 14, 15 and 16 and Exhibits 12-2, 12-3, and 12-4. A summary of this information is <br />included here, below in the Description of the Operations Plan and in Section B, Item III of this <br />document. <br />Most of the permit area drains to Dry Creek. A small, northern portion of the railroad loop <br />drains directly into the Yampa River. Dry Creek flows into the Yampa River near the town of <br />Hayden. Stokes Gulch, an intermittent stream, flows into Dry Creek just south of the Loadout. <br />Precipitation averages approximately 16 inches annually in the permit area and the volume of <br />runoff is limited. Most runoff comes from snowmelt or intense thunderstorm events. Flows in <br />Dry Creek have ranged from 0 to 126 cfs (cubic feet per second) upstream of the Loadout to 0 to <br />225 cfs downstream. Two sediment ponds handle runoff at the Loadout: the Truck Loop Pond, <br />which usually discharges during spring snowmelt, and the Rail Loop Pond, which has rarely <br />discharged. <br />Stream flow in Dry Creek generally increases downstream although some sections are ephemeral. <br />During the growing season, diversions of water from Dry Creek upstream from the permit area <br />can significantly reduce and even periodically eliminate streamflow in the vicinity of the <br />Loadout, while at the same time return flows from surrounding irrigated fields can discharge <br />small volumes of water to Dry Creek below the Loadout. <br />The dominant cations in Dry Creek water are magnesium, calcium and sodium. The dominant <br />anion is sulfate. The pH is generally around 8.2. The concentrations of major cations, total <br />dissolved solids, and nitrate (possibly due to agricultural return flow) increase during periods of <br />low flow (baseflow). Total suspended solids (TSS), aluminum and total iron increase during <br />high flows. Average values for total dissolved solids (TDS) are higher downstream than <br />upstream of the Loadout, with average values of 3,175 and 2,439 mg/1(milligrams per liter), <br />respectively. <br />Please see Section B, Item III of this document for a discussion of the probable hydrologic <br />consequences (PHC) of the Loadout on surface water quantity and quality and for a further <br />discussion of the surface water monitoring plan. Alluvial valley floors (AVF's) are discussed in <br />Section B, Item XIV of this document. <br />Ground Water Hydrology <br />Ground water information is located in Tabs 7, 13, 14 and 15 of the permit application. A <br />summary of this information can be found in Section B, Item III of this document, along with <br />specific findings related to ground water hydrology. <br />