CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Bhamjee, R.; and Lindsay, J.B.
Date : 2010.
Title : Assessing spatial and temporal variability of ephemeral streamflow in southern Ontario.
Publication : Ontario Division of the Canadian Association of Geographers Annual Meeting. October 15-16, 2010. Ryerson University, Toronto, Ontario.
Issue : CAGONT 2010. Book of Abstracts. Edited and compiled by: K. Wayne Forsythe
Page(s) : 27.
Abstract
The episodic expansion of stream networks into their headwater ephemeral channels during storm events can result in transport of sediment and pollutants downstream, particularly in agricultural basins. Unfortunately, the duration and timing of these events are rarely measured. Ephemeral streamflow monitoring has been undertaken in the past using direct observation as well as specialized sensors with varying degrees of success. An electronic resistance (ER) sensor design is presented that allows for the observation of flow events in ephemeral channels and mitigates many of the issues found with previous sensor designs. The design of the novel sensor and the setup of sensor networks in two agricultural basins in Southern Ontario are described, as well as considerations for data processing with regard to monitoring ephemeral streamflow at high spatial and temporal resolutions. Three models of network expansion are described, the duration and timing of expansion are compared to meteorological events and the controls on flow initiation and expansion are assessed based on various catchment characteristics. Just over 83% of observed events followed a coalescence expansion model, with the majority being incomplete coalescence, while upward expansion accounted for just under 10% of expansion events. Upward expansion, together with complete coalescence, show that around 40% of all expansion events connect the ephemeral channel to the flowing stream network. As such, 60% of expansion events can result in potential deposition of pollutants into the channel, but not the movement of those pollutants downstream. This is important when considering the treatment of agricultural fields in relation to when the connecting flow events occur, especially in predominantly agricultural catchments where eutrophication is a problem.
Bibliography of Canadian Geomorphology