MODELING OF NON-POINT SOURCE MANAGEMENT SCENARIOS IN EASTERN ONTARIO USING ANNAGNPS

摘要

The South Nation watershed consists of an area of roughly 3900 km~2 in Eastern Ontario which drains into the South Nation River. The South Nation River in turn drains into the Ottawa River. The watershed encompasses a wide variety of land uses, particularly with respect to agriculture and forestry. Previous studies indicate that the contribution of nonpoint sources (NPS) to nutrient loadings is both significant and poorly defined in the region (Gore and Storrie, 1993; Wilson, 2000). A recent multi-million dollar study of the water resources within Eastern Ontario (CH2M Hill, 2001) and work being conducted by the community-university research association (CURA) workgroup at the University of Ottawa illustrates the need for better models and decision support tools for watersheds of this nature. The work presented here included use of the dynamic Annualized Agricultural Non Point Source (AnnAGNPS) pollutant loading model, developed by the U.S. Department of Agriculture (USDA) and successor to AGNPS 5.0 (USDA, 2001). The AGNPS family is widely used and respected. The AnnAGNPS incarnation introduced several important additions, notably the ability to run continuous-simulation scenarios over extended time periods. In-stream water chemistry was also an important element of a meaningful analysis. The dynamic model water-quality model, CE-QUAL-RIV1 was eventually selected due to its riverine nature, which is closely linked with the AnnAGNPS concept of a channel network. The linked models were then calibrated to the available data, and a case matrix focusing on predicting feasibility of BMPs within the context of climate change was constructed and simulated. Results of the work were then further analyzed through use of several ecological indices to determine the intensity (severity), duration and frequency (IDF) of violations to species survivability occurring within the stream network. Implementation of BMPs to intermediate and maximum extents reduce water quality impacts but stream standards were not reached. Agricultural activity within the watershed must be diminished to reach standards.