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Thursday, June 7, 2007 - 11:00 AM
391
Development of Suspended Sediment Standards for Headwater Streams in Potato Production Regions of Atlantic Canada
Glenn A. Benoy, Ph.D., NWRI (Environment Canada), Potato Research Centre, 850 Lincoln Road, PO Box 20280, Fredericton, NB E3B 4Z7, Canada, Joseph M. Culp, Ph.D., NWRI (Environment Canada) and Canadian Rivers Institute at the University of New Brunswick, 10 Bailey Drive, PO Box 45111, Fredericton, NB NB E3B 6E1, Canada, Robert Brua, Ph.D., NWRI (Environment Canada), National Hydrology Research Centre, 11 Innovation Boulevard, Saskatoon, SK S7N 3H5, Canada, and Clair Murphy, Environment Canada, 97 Queen Street, Charlottetown, PE C1A 4A9, Canada.
Through Canada’s National Agri-Environmental Standards Initiative (NAESI), sediments have been identified as a primary stressor for which standards are needed. Potato (Solanum tuberosum L.) production regions of Atlantic Canada are prone to soil erosion due to rolling topography, high intensity rainstorm events and the persistence of conventional tillage practices. To assess the influence of watershed heterogeneity and agricultural practices on total suspended sediments (TSS) in headwater streams, field sampling programs were established in northwestern New Brunswick and in central Prince Edward Island. TSS was measured at weekly and monthly time intervals and, where available, according to episodic rainfall/discharge events. GIS was used to quantify agricultural intensity within watersheds as coarse land cover (% agriculture), extent of forest cover and riparian zones, and (beneficial management practice) BMP implementation rates. Results to date indicate that background (i.e. “normal” flow periods) TSS is positively related to agricultural coverage. Differences in BMP implementation rates help to explain some of the variation in TSS among watersheds. As fine soil particles and sediments can function as substrate for agriculturally-derived nutrients, pathogens and pesticides, trends observed for TSS are likely to be correlated with other agri-environmental stressors at watershed scales.