SBCT Final EIS - Govsupport.us

Chapter 3 ⎯ Affected EnvironmentGroundwater QualityIndustrial activities associated with USARAK’s use of FRA have had some effects on groundwater.Monitoring has found pollution associated with underground storage tanks, chemical storage facilities,and chemical dump sites. FRA has been identified as a CERCLA site and put on the NPL in1993. Identified groundwater pollutants included TCE and arsenic. Water quality has improved sincedue to Army restoration projects to mitigate previous damage to groundwater quality. Cleanup activitieswere completed in September 2006, and currently contaminated groundwater migration at the siteis under control and no significant risks to human health have been found (USEPA 2007).3.2.2.2 Donnelly Training AreaSurface Water OccurrenceDTA is located within the Tanana Basin, an interior glacial waterway. The major waterway at DTA isDelta River. The Delta River originates at Tangle Lakes, flows north 50 miles to DTA’s southernboundary, then flows 26 miles through the installation, and then another 9 miles to its confluence withthe Tanana River. The Delta River receives significant meltwater from several glaciers as it flowsthrough the Alaska Range (USARAK 2004).Jarvis Creek originates at the terminus of Jarvis Glacier on the north side of the Alaska Range andflows northward for 40 miles through a narrow valley before passing through DTA East and convergingwith the Delta River. Other streams within DTA include non-glacial Granite Creek, which formsthe eastern border of DTA and glacier-fed Buchanan Creek on the south. Glacier-fed Delta Creekdrains the interior portion of DTA West and flows directly into the Tanana River.There are 16 lakes managed by Alaska Department of Fish and Game (ADFG) located within DTA.These lakes are used for recreational fishing. Bolio Lake is the largest of these, at approximately2.5 miles in length. Most other lakes on DTA are not suitable for stocking due to poor accessibility ortheir susceptibility to freezing. The combined area for the lakes and ponds on DTA is 8,752 acres(USARAK 2004).Ice bridges are constructed across the Delta River west of Fort Greely. These bridges allow access towinter training areas, which otherwise would be unreachable from the ground.Water QualityBased on a site-specific USAEHA (1990) study, surface water quality of streams flowing throughDTA meets the state primary drinking water standards. However, aluminum, iron, and manganeseconcentrations exceed the state’s secondary standards. DTA water is of the calcium carbonate typeand is slightly basic. Dissolved oxygen values measured at DTA also exceeded the state’s minimumlevel of 4.0 mg/L.USACE conducted a study of Jarvis Creek, which runs through the most heavily used part of thetraining area (Bristol Environmental and Engineering Service 2003). Based on this study, most of theparameters, including arsenic levels and pH, were within the state drinking water quality standards.Dissolved oxygen and temperature narrowly exceeded the state standard for drinking water, but notthe temperature standard for the general water supply.The average annual suspended sediment yield for the Delta River is 1,200 tons per square mile(Dingman et al. 1971), and the sediment load ranges from 100 to 1,000 mg/L during the open-water(not frozen water conditions) season. Sediment load concentrations also change rapidly with changesFebruary 2008 3–102 2/25th SBCT Final EIS