Document Type

Thesis

Degree Name

Master of Environmental Studies (MES)

Department

Geography & Environmental Studies

Faculty/School

Faculty of Arts

First Advisor

Michael English

Advisor Role

Thesis Supervisor

Abstract

Riparian buffer zones are defined as strips of natural vegetation separating streams or lakes from surrounding upland landscapes. These zones may effectively reduce the nitrate-N load in shallow ground water draining intensively fertilized agricultural regions. Contemporary research has tended to focus on wide, forested riparian zones situated on poorly drained lowland sites. In addition, research has typically focused on the growing season, when the ecosystem is biologically active, with relatively day hydrological conditions. This field study monitored spatial and temporal patterns of nitrate-N in a comparatively narrow, non-forested buffer zone situated in an upland agricultural watershed in southern Ontario. Results show that the nitrate attenuation ability of the buffer zone is spatially and temporally variable. At one site, the buffer zone consistently reduced concentrations of nitrate from input values greater than 10 mg/l, to less than 1 mg/I. At another site, located only 200 m up stream, the reduction of nitrate concentrations was much less. However, the rate of nitrate attenuation in terms of mass was similar at both sites. Temporal variations were observed in the nitrate attenuation ability of both sites. While the ratio of nitrate removed to nitrate input decreased during the dormant season, the actual mass removed increased. Differences in hydrogeological structure and land use associated with the two sites are likely responsible for the different attenuation patterns.

Convocation Year

1999

Convocation Season

Fall

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Hydrology Commons

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