Predicting ground water nitrate concentration from land use

Abstract

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 forest, undeveloped, and high-density residential land 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 > 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.

Analysis of Groundwater Nitrate Contamination in the Central Valley: Comparison of the Geodetector Method, Principal Component Analysis and Geographically Weighted Regression

“…Statistical methods have been used to study the relationship between groundwater nitrate contamination and predictor variables. For example, multivariate statistical methods like ordinary least square regression (OLS) have been applied in many studies to investigate the relationship between groundwater nitrate contamination and land use conditions [19][20][21]. However, OLS has a drawback of overfitting the data by regressing random error in the model rather than the relationship between the variables when there are numerous variables.…”

A meta-analysis and statistical modelling of nitrates in groundwater at the African scale

“…MLR has the strong advantage that regression coefficients can directly be interpreted in terms of the importance of explaining factors. Many studies linking nitrate occurrence in groundwater to spatial variables have employed logistic regression (Hosmer and Lameshow, 1989;Eckhardt and Stackelberg, 1995;Tesoriero and Voss, 1997;Gardner and Vogel, 2005;Winkel et al, 2008;Mair and El-kadi, 2013). According to Kleinbaum (1994), MLR is conceptually similar to logistic regression.…”

Assessing Nitrogen Use Efficiency and Nitrogen Loss in a Forage-Based System Using a Modeling Approach

“…It legally restricts farm manure application to 170 kg N ha´1 [20], addressing farmers to get them to comply with the water quality protection measures. The directive also promotes the management action programs imposed in nitrate vulnerable zones (NVZs) [3,21] and it is strictly linked to other EU policies focused on air and water quality, climate change and agriculture. NO 3´p ollution is a relevant issue for intensive livestock farms where liquid and solid manure as organic effluents are used [22][23][24][25].…”