Assessing the cost and effectiveness of agricultural Beneficial Management Practices to improve water quality at local and watershed scales

Abstract:

Implementing the Beneficial Management Practices (BMPs) is one of the common approaches to reduce non-point source pollution in agricultural areas and improve water quality. The chance of BMP uptake depends on various factors, most importantly on the effectiveness of BMPs and their cost of implementation at local and watershed scales. In this study, we present a set of cost-benefit analyses in order to identify optimal combinations of BMPs to improve the water quality in the Qu'Appelle River Basin (QARB), Saskatchewan, Canada. For this purpose, a series of BMPs related to cattle corral and grain farms, previously selected by the stakeholders in the region, were considered. A water quality model was used to estimate the nutrient export from the tributaries of the QARB before and after the implementation of these BMPs. In addition, a cost module was developed to estimate the operational cost of the BMPs. Results revealed the existence of multiple sets of optimal combinations of BMPs that can significantly reduce the nutrients export with a minimal budget at the watershed scale. However, performing cost-benefit analyses at the tributary scale was necessary since the cost and rates of nutrient abatement vary from a tributary to another. In addition, our analyses showed that the effectiveness of the optimal combinations of BMPs at the watershed scale is influenced by the stakeholders' chance of uptake; thus, their engagement in decision-making processes is highly recommended.