An Economic Analysis of Groundwater Contamination from Agricultural Nitrate Emissions in Southern Ontario

Abstract

This paper analyzes the costs and benefits of controlling groundwater pollution from agricultural use of nitrogen fertilizer in southwestern Ontario. The Village of Hensall, where nitrate concentrations have been observed above 10 mg/L in recent years, is selected as the study site.‘The CREAMS simulation model is used to estimate the effect of reducing nitrogen fertilizer on nitrate leaching and consequently on nitrate groundwater pollution. Estimates of the value of groundwater are obtained from the literature and are used to calculate the off‐farm cost of groundwater contamination. This procedure results in a wide range of values for the benefits of reducing nitrate pollution. Estimated annual benefits of improved ground‐water quality range from less than $1,000 to more than $30,000 for the village. The off‐farm benefits of nitrate groundwater pollution abatement outweigh the cost of using bottled water and also exceed the on‐farm cost of reducing nitrogen fertilizer application rates. Placing a tax on nitrogen fertilizer would reduce the level of nitrogen applications, but the farm cost of compliance to a nitrogen tax policy is substantially higher than the compliance cost under a regulatory policy that imposes a quantitative ceiling on nitrogen application rates over the part of the aquifer from which the village draws its water supply.