GENERAL42877 - Laserfiche WebLink

Home Browse Search

Coal Methane Drainage Project - PaneG 76-24 Wu! E!k Mine • Papt 34 great as the shallow ground water springs. Water from springs is generally more saline than the surface water in the area. There are approximately 37 stock ponds within the mine permit area, of which the majority aze in the project area. The stock ponds are generally located in drainages, and pond water levels are monitored annually. Two adjacent ponds, located in Section 27 in the upper reach of the Sylvester Gulch drainage and referred to as the Two Ponds Sensitive Area, cover a total area of 2 to 3 acres and include an aquatic ecosystem, riparian areas, wetlands, and habitat for cavity-nesting buds (Greystone, Oct. 2001 a). A seep was also mapped approximately 4,400 feet downstream from the two ponds. A 0.1 acre seep/pond, located on section 15 and 22 boundary in the southwest corner of Panel 21, was identified as potentially providing habitat for sensitive species (Greystone, Oct. 20016). MCC maintains monitoring stations and regularly monitors flows and water quality on Minnesota Creek, Dry Fork, the North Fork, Horse Gulch, Deep Creek, and Sylvester Gulch. Flow measurements and field parameters aze typically collected three times per year (spring, summer, and fall) and water quality sampling and analysis occurs annually. Commitments for future monitoring aze tied to initiation of active mining within a watershed azea, with initial monitoring at least one year in advance of mining disturbance. In compliance with the terms of their approved CDMG mining permit, MCC will continue monitor surface water flows and quality for all potentially affected surface drainages that overlie active mining areas. 3.1.1.4 Ground Water Shallow Quaternary alluvial and colluvial deposits above bedrock are the principal ground water bearing units in the azea, particulazly along the North Fork and larger tributaries. colluvial and/or alluvial deposits generally line area drainage bottoms but are limited in extent both laterally and in thickness. Typical depths are less than 100 feet. Thickness of the alluvial/colluvial materials varies with stream gradient. They are typically thinner in the smaller, steeper upper stream reaches and thicker as gradient decreases in the middle and lower reaches of area drainages. These deposits aze typically stratified, with upper zones that aze recharged from streamflows under high flow conditions and direct infiltration of runoff from precipitation and snowmelt. Under low flow conditions, the saturated alluvial/colluvial deposits may release water to area streams, effectively extending streamflows. Given the semi-arid conditions in the area and relatively steep stream gradients, many of the smaller drainages do not receive enough water to maintain long-term flows or to saturate the alluvial/colluvial deposits. Most springs and seeps issue from colluvial deposits underlain by less permeable bedrock. Some have been developed for livestock watering and to support wildlife. Surface materials and associated shallow groundwater and seeps have the following general chazacteristics: • Flows change dramatically through the yeaz, with high flows following spring snow melt • Alluvial sediments may have significant water transmission capacity • Alluvial sediments often have limited storage volume relative to recharge and dischazge rates • Sediments aze often hydrologically connected with surface water flows The alluvial/colluvial water-bearing zones may be hydraulically connected with adjacent bedrock and intermixing of waters may occur. In addition, changes in surface water expression may either cause or result from landslide events. The North Fork alluvial aquifer is the source of drinking water for the town of Paonia. The alluvial ground water is typically acalcium-bicarbonate type water with good quality and moderate hazdness, m~iaa/m...e, rrc/~inM i~•~n: er usr'r eirioz er Environmental Arrecrment