Engineering Within Ecological Constraints (1996) / Chapter Skim
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Engineering Studies Based on Ecological Criteria
Engineering Studies Based on Ecological Criteria
Pages 177-186
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From page 177... ...
defined sustainable development as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs" (World Commission, 1987~. Many international and national organizations, including the United Nations, UNESCO, World Bank, and the Earth Council have held meetings to discuss various concepts of sustainable development and sustainability indicators.
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From page 178... ...
If the ecological criteria for certain species can be determined, then an alternative is to restore or maintain the river basin according to their specific needs, such as flow parameters required by different life stages, the magnitude and frequency of flooding, acceptable levels of sediment in the flow, and various water quality limits. A great deal of research is needed to understand the ecological criteria for many ecological elements under various hydrologic conditions.
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From page 179... ...
Kissimmee River Restoration Studies The channelization project in the Lower Kissimmee River Basin, Florida, resulted in severe losses of river floodplain wetlands and waterfowl populations throughout the river valley. An earthen channel, the C-38 canal, is the main element of this project.
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From page 180... ...
These ecological criteria must be satisfied while simultaneously meeting independent constraints for flood control, navigation, and sedimentation. The main engineering approaches were to divert flows to the river's original course and its floodplain by blocking the C-38 canal with hydraulic structures such as weirs and earth plugs.
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From page 181... ...
A piecemeal restoration program in which some of the established restoration criteria are achieved in one segment of the system, and other criteria are met in another portion, will not accomplish restoration goals and may be of little or no value. Game fish populations, for example, may still be limited if appropriate flow characteristics are restored but production of potential food resources on the floodplain is limited by inadequate inundation, or inaccessibility to river fish because levees or berms block the connectivity (interaction)
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From page 182... ...
Three alternative restoration plans have been selected by the District for analysis. In the Fixed Weir Plan, 10 weirs would be installed along the canal to divert flows into the river oxbows adjacent to the weirs.
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From page 183... ...
It is nearly impossible to design complex flow operation schemes to control both inflows and outflows from each pool to reduce the recession rate because the capacity for flood flow under this plan would be greatly reduced by the earth plugs blocking the canal. The amount of time that given proportions of the floodplain would be inundated under this plan is slightly less than would be inundated under the Fixed Weir Plan, and these values are far from meeting the requirements for ecological restoration.
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From page 184... ...
Certain portions of the stream below the proposed Norden Dam would be unavoidably changed from braided to meandering by the release of flows with relatively small amounts of sediment particles from the reservoir. We planned to maintain the braided characteristic of the river farther downstream by regulating the flow, controlling vegetation growth, and even breaking the ice jams that form annually.
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From page 185... ...
West Palm Beach, Fla.: South Florida Water Management District.
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