ENV100Y5 Lecture Notes - Lecture 41: Saltwater Intrusion, Diversion Dam, Groundwater Pollution
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ENV100Y5 Full Course Notes
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Chapter 12 - part 2. Wednesday, january 13, 2016. Human use of surface water has environmental impacts. Downstream and trans- boundary impacts - water flows from one jurisdiction to another (no limitations) Changes in erosion and siltation rates. Evaporative loss from reservoirs and irrigation. Impacts on habitat, wildlife, ecosystems. We have erected thousands of dams. Dam = obstruction to block flow of water in a river so water can be stored in a reservoir. Diversion dam = water diverted but not stored in reservoir. Prevent floods, provide drinking water, allow irrigation, generate electricity. 45,000 large dams have been erected in more than 140 nations. Benefits and drawbacks of dams. Shipping - control river flow. Sediment capture @ dam base. Removing dams restores riparian ecosystems, fisheries, river recreation. In canada only a few dams removed to bring back the original state. Today, 70% more water withdrawn for irrigation than in 1960. Consumptive use (removes the water from that drainage basin)
