SBCT Final EIS - Govsupport.us

Chapter 5 – Environmental ConsequencesAt FTC, Alternative C may result in impacts to surface water quality due to increased erosion andsedimentation related to training activities and construction of new facilities. Other impacts includeincreased loading to the existing stormwater system, impacts on water quality from munitions use,spills and leaks, and depletion of groundwater resources from staffing increases. At PCMS, impacts tosurface water quality may occur from increased erosion and sedimentation related to maneuvertraining and potential impacts on water quality from spills and leaks. All of these impacts areconsidered less than significant.5.4.3.1 Impacts from Cantonment ConstructionLess Than Significant ImpactsNonpoint source contamination of surface water and groundwater. No cantonment construction toaccommodate the addition of 663 Soldiers, their families, support personnel, and SBCT-specificfacilities would be required at FTC initially to accommodate the permanent stationing of the 2/25 thSBCT at FTC. The initial needs would be met by the facilities being vacated by the 4/4 th IBCT thatthe SBCT would be replacing. The associated facilities needs for the SBCT would not be significantlydifferent from the current needs at FTC that are on going as part of the transformation at FTC and anyfuture construction is likely to occur in previously disturbed areas of the cantonment. Temporarily,Stryker vehicles would be parked in vacant fields within the cantonment area until a future date whenpermanent parking would be developed to make up the identified shortfall of approximately 20,000square yards. Future construction activities and temporary parking could result in short-term,localized increases in erosion and runoff. Use of heavy construction equipment would causecompaction of near surface soils that could result in increased runoff and sedimentation. Clearing andgrading during construction would expose the soils to erosion. Dewatering may also be needed duringconstruction, particularly for the utility trenches. However, engineering controls and BMPs includingSWPP Plan would be used to minimize these potential impacts during construction.Construction and operation of new facilities would increase the use of fuels, solvents, and otherhazardous and toxic substances, which might result in indirect impacts to surface and/or groundwaterif accidentally released into the environment. Fort Carson would implement BMPs and the SPCC toaddress leaks or spills of hazardous materials. Potential spills would be typically small in magnitudeand localized. Even a large, uncontained spill, however, would have a low probability of affectingsurface water, as the streams at FTC are intermittent. In addition, Fountain Creek is on the oppositeside of a major highway (I-25), making it highly unlikely for any spill to directly or indirectly affectthis water body.Groundwater from nine existing wells is used at FTC for natural resource support and rehabilitation,support of training capabilities, and fire suppression. Increase in personnel stationed at FTC related tothe permanent stationing of the 2/25 th SBCT may result in increased groundwater use. This increase,however, would be small enough (16 percent) that it could likely be accommodated under existingsubsurface water rights.Stormwater runoff. The stormwater conveyance system, utilities, and ditches within the cantonmentarea may be unable to handle the increased loading from additional construction and facilitiesoperation, even with the upgrade of the “B” Ditch and the Magrath/O’Connell drainage system.Insufficient capacity in the stormwater conveyance system could result in adverse affects tofloodplains in the cantonment under this alternative. Implementing the remaining phases of theUSACE (2005b) study would address shortcomings in the stormwater system.February 2008 5-139 2/25th SBCT Final EIS