EESC 1158 Lecture Notes - Aggradation, Bed Load, Wetting
11 Mar 2014
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Document Summary
Downstream effects of dams: changed hydrographs i. ii. iii. Rio grande: reduced total and flood flow: tributaries still deliver sediment to the river, channel aggradation and narrowing: need to build levees to keep channel out of floodplain. Platte river, ne: water supply for irrigation: braided, sand bedded, dynamic, adjustable, pre-dam average: 18,000 ft3/s (510 m3/s, post-dam average: 2,500 ft3/s (71 m3/s) (cid:0) dams/diversions reduce total flow. Vegetation growth in channel area (due to lack of floods) Conversion from braided toward single channel morphology ii. iii. iv. (cid:0) loss of habitat in wide channels. Snake river, id-or: power generation: little change in total or flood flow, large daily fluctuations, sediment trapping behind dams, erosion of sandbar downstream from dams. Sand bar erosion: loss of habitat, recreation opportunities. Multiple use dams: multiple effects, multiple constituencies, chattahoochee river, ga, green river, ut, colorado river, ut.
