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Bottomland Hardwood Forests: Their Functions and Values
Published in James G. Gosselink, Lyndon C. Lee, Thomas A. Muir, Ecological Processes and Cumulative Impacts, 2020
Jan R. Taylor, Milady A. Cardamone, William J. Mitsch
Channelization of rivers and streams involves removal of natural meanders, streambank clearing, increases in channel depth and width, and disposal of dredged materials. The purposes of channelization include navigation improvement, flood control, and production of arable land. By straightening and deepening the stream, the movement of water is improved. Consequently, flooding in the bottomland adjacent to a channelized stream segment is reduced or eliminated. This severely decreases the water, sediment, and nutrient subsidies that make the bottomland hardwood forest so productive. On the other hand, the flood storage capabilities of the bottomland hardwood forest have largely been bypassed, and flooding in unchannelized downstream segments will be much more severe. Deepening the channel also encourages the discharge of groundwater from the bottomland to the stream. This creates a reduction in soil moisture which, along with reduced nutrient input, stresses the flood-adapted vegetation and decreases primary productivity.
Environmental Impact Studies for Channelization Projects
Published in Larry Canter, Environmental Impact of Water Resources Projects, 1985
Environmental impact studies for channelization projects typically address 3 to 5 alternatives. In their literature review, Thackston and Sneed (1982) addressed a number of alternatives to traditional channel modification. Structural alternatives to channel modification include levees, floodways, reservoirs, and land treatment measures. Additional alternatives include various forms of flood plain management; flood plain zoning; construction of bypass channels around sensitive wetland areas; construction of numerous, very small, water-retention structures; and substitution of clearing and snagging, or only snagging, for complete channelization.
River engineering
Published in Mohammad Albaji, Introduction to Water Engineering, Hydrology, and Irrigation, 2022
River engineering methods are divided into two categories based on the overall purpose. When the purpose of river engineering is to improve flow, especially in flood conditions, is called channelization and when the purpose is to hold back the flow, primarily for navigation purposes, is known as canalization.
A framework for assessing flood risk responses of a densely urbanized watershed, to support urban planning decisions
Published in Sustainable and Resilient Infrastructure, 2023
Antonio Krishnamurti Beleño de Oliveira, Lucas Magalhães Carneiro Alves, Carolina Lopes Carvalho, Assed Naked Haddad, Paulo Canedo de Magalhães, Marcelo Gomes Miguez
Most of the Metropolitan Region of Rio de Janeiro (MRRJ) is on flat floodplain areas. Extensive channelization has been used as the main flood mitigation strategy to drain these regions, seeking to allow safer urban occupation. After the accelerated urban growth experienced in the last century (Helders, 2005) and the consequent increase of runoff generation, most of these channels are no longer able to capture and convey rainwaters during intense rainfall events. Moreover, the rivers in the MRRJ outflow into the Guanabara Bay. At high tides, the backwater effect caused by water levels rise in the river mouth hinders water conveyance, reducing the outflow rates of coastal watersheds. These characteristics make this region very susceptible to climate change effects because the possible rise in mean sea level can be combined with possible increases in rainfall intensity aggravating flooding in this area.