Laserfiche WebLink
• <br />• <br />• <br />Exhibit G - AMENDMENT 4 <br />Water Information <br />This exhibit presents an inventory of existing water resources at Pueblo East Pit and a discussion <br />of water requirements of the mining plan for Pueblo East Pit Phase 7 and how those requirements <br />will be met. There are surface water and ground water resources at the Pueblo East Pit. <br />(a) Summary of Local Surface and Ground Water Systems <br />The surface water in this area consists solely of the Arkansas River. No appreciable tributaries <br />join the river as it passes through the permit area. The Arkansas River is a broad, swift flowing <br />and meandering river at this location. Based on 36 years of stream gage data (1976 - 2010) from <br />the USGS near Avondale, CO, the average annual flow in the River is approximately 664,000 <br />af/yr at this location. There are no springs, stock water ponds, reservoirs or irrigation ditches on <br />the affected lands or on adjacent lands that may be affected by the proposed mining operations. <br />The alluvial ground water system is connected to the surface water system and has its own <br />unique characteristics. The ground water system consists of the alluvial aquifer deposited by and <br />hydraulically connected to the Arkansas River. On average, the alluvium is approximately 5,700 <br />feet wide and has a saturated thickness of 20 to 30 feet in the permit area. The aquifer is <br />essentially shaped like a trough with the thickest areas occurring near the river and thinning <br />away from the river. The base of the aquifer (which is also the top of the underlying shale <br />bedrock unit) is fairly irregular, resulting in varying saturated thickness across the aquifer. The <br />shale bedrock is not relied upon as a ground water supply in this area. <br />(b) Projected Changes that May Occur in the Alluvial Aquifer <br />Production wells are constructed in the alluvial aquifer which serve domestic, irrigation and <br />commercial uses. Dewatering of sand and gravel deposits during Phase 7 mining will lower the <br />ground water table outside of the mining permit area. Changes in ground water levels may <br />impact yield from some nearby water wells, while water level changes in other wells will not <br />affect well yield. Based upon experience from nearby domestic and commercial water wells, five <br />1 <br />