Background
Agriculture can significantly impact surface water quality, resulting in the contamination of downstream waterways and water bodies with sediments and phosphorus. Development of effective Beneficial Management Practices (BMPs) to minimize adverse impacts on water quality requires a sound understanding of the sources of sediments and associated phosphorus within these ecosystems.

Project
We are working in three watersheds: South Tobacco Creek Watershed in Manitoba, Black Brook Watershed in New Brunswick, and Bras d'Henri Watershed in Quebec.

In these watersheds, not all of the sediment and phosphorus being redistributed within agricultural fields by runoff and erosion is leaving the fields and entering surface waters. And, not all of the sediment and phosphorus that leaves a watershed is coming from the agricultural fields. In-stream processes can result in significant generation, transport, deposition and remobilization of sediments and phosphorus. Apportioning contributions from various sources within a watershed is essential to evaluating the effectiveness of BMPs in protecting water quality.

We are using environmental fingerprinting techniques to build upon the traditional techniques (surveys and budgets) being used to assess the sources and fates of sediments and phosphorus within these agriculture watersheds. Fingerprinting, also known as tracking or sourcing, is based on the principle that materials entering the water have a chemical and physical signature that reflects their origin.

We are using a suite of radioisotopes; compound-specific stable isotopes; shape and colour, as well as the size of sediment particles; and multiple tracers to assess cost effectiveness. A variety of statistical models will be examined for their utility in discriminating sources, and improvements will be made to the methods of source discrimination.

Our students are writing manuscripts, and have published papers and posters on their work. To find out more see the following examples:

Alexander J. Koiter, David A. Lobb, Philip N. Owens, Ellen L. Petticrew, Kevin H. D. Tiessen, Sheng Li. 2013. Investigating the role of connectivity and scale in assessing the sources of sediment in an agricultural watershed in the Canadian prairies using sediment source fingerprinting. J Soils Sediments DOI 10.1007/s11368-013-0762-7

Cenwei Liu. 2014. Spatial and Temporal Variation in size and shape of sediment particles in the Tobacco Creek watershed.  Master of Science Thesis, University of Manitoba Winnipeg, Manitoba