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Reclaiming reservoirs : native species revegetation of shorelines

British Columbia Mine Reclamation Symposium; University of British Columbia. Norman B. Keevil Institute of Mining Engineering

B.C.Hydro operates over 40 reservoirs in its utility system. In addition to supplying electricity, many of these reservoirs provide multiple uses to the local communities such as fishing, boating, swimming and wildlife viewing. The operation of a hydroelectric dams often produces fluctuations in reservoir levels due to inequalities in daily water use and seasonal inflows. These fluctuations, or drawdowns, limit the capability of native vegetation to survive along shorelines. Without the binding effects of plant roots, fine, silty materials are easily eroded by wind and water. Recently, B.C.Hydro has experimented with the reclamation of drawdown zones using native wetland plant species. Studies began in the early 1980's in response to dust problems caused by wind erosion when reservoirs were at low water levels. The early findings indicated that local wetland species were limited in the drawdown zones largely by the inability to develop quickly enough to survive water inundation. There is often a plentiful seed supply, however, once seeds establish they cannot withstand the prolonged high water periods. B.C.Hydro has used several simple methods to encourage seedling establishment in the drawdown zones of reservoirs. A broad nurse crop of local or temporary grass mixtures can protect young seedlings from wind and water erosion while providing necessary organic matter. Experimental nurse crops have been applied using broadcast, seed drills, hydro-seeding or heli-seeding methods. In addition, planting greenhouse grown seedlings in the drawdown zones has proven effective. The seed is collected from local plant communities to take advantage of the regional species adaptations to climate and soil conditions. Collected seeds are treated and germinated in a greenhouse to increase their chance of surviving inundation when replanted in the drawdown zone. There has also been some success with planting local willow cuttings in higher elevations of the drawdown zone. Vegetated reservoir shorelines benefit the local community by decreasing water and wind erosion and increasing the quality of visual and recreation resources. The benefits to the ecosystem include an increase in habitat productivity and diversity, and greater riparian habitat for fish and wildlife use.

Conference Paper

application/pdf

2009-07-14

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/10797

Unreviewed

British Columbia Technical and Research Committee on Reclamation

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