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2007 Ground Water Summit |
Monday, April 30, 2007 : 11:10 a.m.
Ground Water Modeling as a Tool for Spill Site Management Associated with a Municipal Well Field in Wappingers Falls, New York
A ground water model was constructed to evaluate the potential for migration of constituents from a 12,000-gallon gasoline spill site to the nearby Atlas Municipal Well Field serving the Wappingers Falls, New York community. The model was constructed using available information from a number of sources including spill site investigations, Atlas Well Field exploration and pumping tests, and regional exploration and monitoring information that was publicly available. The model was constructed and calibrated in collaboration with state agencies, local water authorities, and the various consultants engaged by the interested parties. The calibrated ground water model was then used to evaluate the effect of surface water stage fluctuation on contaminant migration and the surrounding alluvial aquifer; ground water flux rates into and from the adjacent stream; drought scenarios under existing pumping rates and proposed system expansion rates; and the adequacy of the existing monitoring network for protecting the town’s ground water source from spill site related constituents. The results of the modeling effort and sensitivity analyses indicated that the existing monitoring network was sufficient for the task of ensuring well field water quality and there was limited risk to the well field posed by the upstream spill site. The willing participation of all the interested parties in the modeling effort led to a defensible, peer reviewed model that served as a highly effective tool for evaluating concerns raised by multiple project stakeholders and for communicating project results.