Response of stormwater retention basins to two chemical aquatic weed control methods |
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Authors: | SC Wakelin P Elefsiniotis DG Wareham |
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Institution: | 1. Wardrop Engineering Inc. , 400-386 Broadway , Winnipeg, MB, Canada;2. Department of Civil and Environmental Engineering , University of Auckland , Private Bag 92019, Auckland, New Zealand;3. Department of Civil Engineering , University of Canterbury , Private Bag 4800, Christchurch, New Zealand |
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Abstract: | The City of Winnipeg, Canada has 70 stormwater retention basins (SRBs) whose primary function is to act as land-drainage, storage reservoirs within the city. The ponds often become choked with vegetation and this disenchants property owners who have been led to believe, by subdivision developers, that the ponds are pristine ‘lakes’. The City has implemented some control measures to help alleviate customer dissatisfaction by removing vegetation using the herbicides Karmex-DF and Reglone-A. For this study, in order to evaluate herbicide control methods, water quality was assessed on 10 occasions, biweekly over the 5 months of a Canadian summer (May to September), on 37 of the SRBs. Various water quality parameters were determined, including total suspended solids (TSS), chlorophyll-a, turbidity, transparency, ammonia, nitrate, orthophosphate, temperature, dissolved oxygen, and pH. By comparing the water quality data resulting from the two aquatic weed control measures, it was established that neither herbicide method seemed to be as effective as the natural ability of the ponds to limit vegetative growth. It is suggested that utilization of the herbicide as a long-term aquatic weed control measure should therefore proceed with caution and perhaps, other alternative methods of control could also be investigated. |
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Keywords: | Stormwater retention basins Water quality Chlorophyll-a Herbicides Chemical control methods |
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