............ Nutrient and Sediment Research 

South Tobacco Creek Project: Nutrient and Sediment Research  

The third major research initiative to emerge from the South Tobacco Creek Project has focused on exploring the linkages between agricultural nutrients and the enhancement of eutrophication. 

Jean-Guy Zakrevsky of Environment Canada is leading this project, which has developed since 1992.  Concern has risen in recent years with the realization that fisheries and tourism-related activities were being threatened by a decline in the health of the aquatic ecosystem of Lake Winnipeg and the $42 million local economy it supports.  As the water in Lake Winnipeg is collected from a huge drainage area, Environment Canada felt it would be prudent to investigate potential nutrient sources upstream.  This investigation began with studies in one of the area's smaller upstream watersheds - The South Tobacco Creek.  

 
Lake Winnipeg: a classic prairie eutrophic lake.
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The Nutrient / Sediment Research project's objectives are:
.....1. To examine potential links between the agricultural use of synthetic fertilizers and eutrophication;
.....2. To comprehend the movements and origins of all nutrients (synthetic and natural sources)
.....3. To foster discussion of the design of this study and to help make recommendations toward filling the main gaps in our collective knowledge of the physical, chemical, and biological processes at play within the South Tobacco Creek Watershed.
Nutrient and sediment monitoring occurs near the upper reaches of the STC watershed at the Twin Watersheds and is ultimately compared to research results further downstream within the South Tobacco Creek.  
 
The Twin Watershed: Major Research Site in the South Tobacco.
 
 
 
Preservation of Water Quality throughout the Red River System to Lake Winnipeg is the Ultimate Goal.
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The South Tobacco Creek watershed is known to deliver significant quantities of sediments downstream during spring runoff and major rainfall events .  With approximately 75% of the watershed in agricultural land-use, a substantial portion of the land base receives nutrient applications.  There are also numerous livestock operations within the watershed.  Several of these are situated close to streams.  Significant field application of nutrients also occurs via manure spreading.  The potential therefore exists for the release of excess nutrients to the aquatic environment. 

Recommended Safe Levels of N and P in the South Tobacco Creek Region. 

1995 N guidelines for drinking water were 10 mg/L of nitrate or 1.0 mg/L of nitrite, combined nitrogen not to exceed 10.0 mg/L.  For aquatic life, total nitrogen should be limited to prevent excessive aquatic plant growth.  Ammonia is toxic to fish.  Depending on pH and temperature, N levels should be in the range of 2.5 mg/L. 

The phosphate recommended objectives are: 0.1 mg/L for flowing streams, and 0.05 mg/L for ponds or lakes.  P does not seem to be toxic but does enhance algae and aquatic plant growth leading to eutrophication problems. 

The best means of learning more about the movement of nutrients and sediments in water courses is to study changes at a measurable watershed level.  Very little accurate data exists in Manitoba, or elsewhere for that matter, regarding the linkage between present levels, time of application, and movement for specific agricultural nutrients within an agricultural watershed.  The Deerwood Association, in conjunction with its South Tobacco Creek Project partners, is now contributing to an increased understanding of these issues. 

 
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