HR: 0830h
AN: H41F-1055    [PDF]
TI: Predicting Groundwater Nitratre Concentration from Land Use in Nantucket, Massachusetts
AU: * Gardner, K K
EM: kristinkiara@hotmail.com
AF: Kristin Gardner, Montana State University Department of Land Resources and Environmental Sciences, Bozeman, MT 59717-3120 United States
AU: Vogel, R
EM: richard.vogel@tufts.edu
AF: Richard Vogel, WaterSHED Center Department of Civil and Environmental Engineering Tufts University, Medford, MAs 02155 United States
AB: Ground water nitrate concentrations on Nantucket Island, Massachusetts were analyzed to assess the effects of land use on ground water quality. Exploratory data analysis was applied to historic ground water nitrate concentrations to determine spatial and temporal trends. Maximum likelihood Tobit and logistic regression analyses of explanatory variables that characterize land use within a 1000-foot radius of each well were used to develop predictive equations for nitrate concentration at 69 wells. The results demonstrate that historic nitrate concentrations downgradient from agricultural land are significantly higher than nitrate concentrations elsewhere. Tobit regression results demonstrate that the number of septic tanks and the percentages of high-density residential, undeveloped and forestland within a 1000-foot radius of a well are reliable predictors of nitrate concentration in ground water. Similarly, logistic regression revealed that the percentages of forest, undeveloped and low-density residential land are good indicators of ground water nitrate concentration greater than 2 mg/L. The methodology and results outlined here provide a useful tool for land managers in communities with shallow water tables overlain with highly permeable materials to evaluate potential effects of development on ground water quality.
DE: 1803 Anthropogenic effects
DE: 1831 Groundwater quality
SC: Hydrology [H]
MN: 2003 Fall Meeting