ABSTRACT: Monitoring water quality on agricultural fields and small watersheds in Quebec

CGRG Bibliography of Canadian Geomorphology
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Abstract

Water quality in agricultural watersheds in Eastern Canada is a matter of great public concern, as nutrient and pesticide concentrations often exceed water quality guidelines. The situation with phosphorus (P) in Quebec is particularly problematic, as concentrations above 0.03 mg/L are commonly found in rivers draining agricultural lands, and this has resulted in the eutrophication of some water bodies. Agricultural non-point source pollution (NPS) has been identified as the principal source of this P. The adoption of Best Management Practices (BMP’s) is an effective approach for reducing agricultural NPS pollution. The development, evaluation and demonstration of BMP’s necessitates water quality monitoring at the field and small watershed scales. However, very little discharge or water quality data is available at these scales. The absence of data may, in part, be due to the difficulties associated with executing monitoring programs. The dominant annual hydrologic event occurs during the winter/spring snow melt and partial melts in mid-winter are not uncommon. Equipment must be fully functional during these periods. Agricultural tile drains are an important hydrologic pathway, but the outlets of these drains are almost always submerged during large events. Response times are rapid at these scales, which necessitates automated sampling equipment. This further necessitates power and heat and where possible, real time monitoring capabilities. In this paper, we present an overview of four (4) agricultural water quality monitoring projects that have been conducted by the Brace Centre. The first project involved monitoring tile drainage and surface runoff from 24 research plots, each of which were 0.12 ha in area. The second project involved measuring surface runoff and tile drainage on two field sites (6 ha and 10 ha). The third project involved the monitoring of paired agricultural watersheds (26.9 and 17.9 km2) to detect changes in water quality as a function of BMP adoption. The fourth project involved monitoring five sampling points in a constructed wetland, to evaluate treatment efficiencies. In addition to an overview of the instrumentation, a discussion of the some of the positive and negative aspects of each project is presented, as well as some operational guidelines and costing information.

Bibliography of Canadian Geomorphology