LE3 .A278 2011

2011

Hebb, Dale
Spooner, Ian

Acadia University

Bachelors of Science

Honours

Environmental Science

Earth & Environmental Sciences

The surface water quality of freshwater systems is an indicator of the overall health of an ecosystem. Nitrogen and phosphorus are limiting nutrients in freshwater systems, so slight increases in either nutrient can negatively affect surface water quality. Agricultural practices dominate approximately 50% of the Thomas Brook watershed, which is located in the Annapolis Valley of Nova Scotia, so nitrogen and phosphorus are used as fertilizers in high amounts during the growing season. This research project focuses on the movement of nutrients from agricultural land into the watercourse during periods of precipitation and their effect on the health of the watershed. An analysis of the surface water quality of Thomas Brook during three periods of moderate to heavy rainfall, estimated to exceed 20 millimetres, in the spring of 2011 determined the increase in nutrient concentrations as a result of excess water and sediment input from overland flow and throughflow. Results from this study show that the nutrient pathway from land surfaces into local surface water during rainfall events differs depending on the nutrient fraction and is a function of the slope of the landscape, duration of precipitation, and/or grain size of the till within the watershed. Major findings indicate that total phosphorus migration is correlated with sediment movement due to overland flow. Nitrate migration into Thomas Brook occurs as a result of throughflow and this fraction only entered the watercourse during periods of long-duration precipitation. The pathway of migration of these nutrients may aid in verifying the efficacy of beneficial management practices that have been implemented within the Thomas Brook watershed.

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https://scholar.acadiau.ca/islandora/object/theses:858