Resilience measure: Floodplain excavation

definition

Floodplain excavation is a measure by which gradual height increase caused by sedimentation on flood plains may be counteracted. The floodplain can be enlarged by lowering the level or increasing the width of the floodplain. Enlarging the floodplain will create more room for the river thereby increasing the discharge capacity and provide upstream retention. The risk of flooding is decreased as the capacity of the river to convey water is increased.
(Climate app, Floodplain excavation or enlargement, accessed on Sept. 2016)
Floodplain excavation may be combined with clay mining and dike reinforcement, and/or with nature development. The removal of hydraulic obstacles is another way to increase its discharge capacity without increasing its water level.Examples of hydraulic bottlenecks include ferry ramps, bridge abutments, high-lying areas, summer embankments that are high and/or perpendicular to the flow direction, narrowing of winterbeds and other obstacles.
(Knight D.W. and Shamseldin A., 2006, p. 546)

Co-benefits and impacts

The remodelling of the river and floodplains creates opportunities for natural and recreational development.
(Climate app, Floodplain excavation or enlargement, accessed on Sept. 2016). While flood plain excavation is an effective way to reduce flood heights it is also the most expensive measure. Soil excavation is expensive in and of itself, but it is the necessary storage and containment of contaminated soil that substantially increases the costs.
(Knight D.W. and Shamseldin A., 2006, p. 546)

conditions

In some areas a floodplain cannot be increased in size as the river is bordered by cities. Widening the river upstream may be a solution as excessive water can be temporarily stored before it is allowed to pass through the city.
(Climate app, Floodplain excavation or enlargement, accessed on Sept. 2015)

Related Links

Approaches (Show all)

Protection






Time scales (Show all)

Long term

Synonym of Resilience Measures (Show all)

Floodplain enlargement





Last modified: Jan. 18, 2017, 12:19 p.m.