Integrated agro-hydrological modelling and economic analysis of BMPs to support decision making and policy design
Abstract
With recent efforts and increasing control over point source pollution of freshwater, agricultural non-point pollution sources have become responsible for most of sediment and nutrient loads in North American water systems. Environmental and agricultural agencies have recognised the need for reducing eutrophication and have developed various policies to compel or encourage producers to best management practices (BMPs). Addressing diffuse pollution is challenging considering the complex and cumulative nature of transport processes, high variability in space and time, and prohibitive costs of distributed water quality monitoring. Many policy options exist to push producers to adopt environmentally desirable behaviour while keeping their activity viable, and ensure equitable costs to consumers and tax payers. On the one hand, economic instruments (subsidies, taxes, water quality markets) are designed to maximize cost-effectiveness, so that farmers optimize their production for maximum profit while implementing BMPs. On the other hand, emission standards or regulation of inputs are often easier and less costly to implement. To study economic and environmental impacts of such policies, a distributed modelling approach is needed to deal with the complexity of the system and the large environmental and socio-economic data requirements. Our objective is to integrate agro-hydrological modelling and economic analysis to support decision and policy making processes of BMP implementation. The integrated modelling system GIBSI was developed in an earlier study within the Canadian WEBs project (Watershed Evaluation of BMPs) to evaluate the influence of BMPs on water quality. The case study involved 30 and 15 year records of discharge and water quality measurements respectively, in the Beaurivage River watershed (Quebec, Canada). GIBSI provided a risk-based overview of the impact of BMPs (including vegetated riparian buffer strips, precision slurry application, conversion to grassland and no-till) in terms of sediment, nutrient and pesticide yields and loads. Input data included characteristics of reservoirs, land cover, soil, agricultural management, livestock management and point sources of pollution. The present study continues from there by first assessing the cost-effectiveness of different sets of BMPs, based on farm budgets and environmental criteria selected by the user. We subsequently examine monetary trade-offs between on-farm costs and social value of water quality improvements using cost-benefit ratios. Because water quality is a non-excludable and non-rivalrous good, its benefits to society are evaluated with non-market evaluation techniques mostly based on quality-constrained recreational use of water. From a policy perspective, cost-effectiveness analysis is very helpful in assisting the decision maker in the highly complex process of defining priorities with respect to BMP strategies. With a user-friendly interface for economic analysis integrated into GIBSI, watershed organizations and stakeholders can use such a tool to promote sustainable agricultural practices and water use. This submission is part of Watershed Evaluation of BMPs project (WEBs) funded by Agriculture and Agri-Food Canada and Ducks Unlimited Canada
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.H31I1270M
- Keywords:
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- 1847 HYDROLOGY / Modeling;
- 1880 HYDROLOGY / Water management;
- 6304 POLICY SCIENCES / Benefit-cost analysis;
- 6309 POLICY SCIENCES / Decision making under uncertainty