On-line structure

Flood risk management and land drainage activities

Activity and function

Potential hydromorphological change

Mitigation measures

Point structure (pipe, inlet, outlet, off-take)

To enable controlled discharge of water through the flood defence

Change in flow dynamics

Loss of structure and condition of the riparian zone

Improve Fish Passage

Remove Obsolete Structure

Sluice

To increase upstream water levels and/or detain discharge

Regulation of flow regime by impoundment

Change in flow dynamics

Change in sediment regime (rivers)

Disruption to river continuity (rivers)

Modify or Enhance Structure

Good Practice Sediment Management

Improve Fish Passage

Remove Obsolete Structure

Manage and Restore Aquatic and Riparian Habitats

Barrier or barrage

To prevent / reduce high water levels in flooding situations while allowing discharge and navigation in non-flooding situations. To allow storage of water for flood defence, water supply, power generation (plus secondary functions)

Change in flow dynamics

Disruption to river continuity (rivers)

Regulation of flow regime by impoundment

Modify or Enhance Structure

Improve Fish Passage

Good Practice Sediment Management

Remove Obsolete Structure

Manage and Restore Aquatic and Riparian Habitats

Culvert

To enable conveyance of water across other functions, e.g. transport infrastructure

Change in flow dynamics

Loss of morphological diversity (rivers)

Loss of structure and condition of the riparian zone

Modify or Enhance Structure

Improve Fish Passage

Good Practice Vegetation Management

Remove Obsolete Structure

Manage and Restore Aquatic and Riparian Habitats

Weir

To increase upstream water levels and/or detain discharge or address slope changes

Change in flow dynamics

Disruption to river continuity (rivers)

Regulation of flow regime by impoundment

Modify or Enhance Structure

Improve Fish Passage

Good Practice Sediment Management

Manage and Restore Aquatic and Riparian Habitats

Remove Obsolete Structure

Reservoir or flood storage area

To allow storage of water for flood defence, water supply, power generation (plus secondary functions)

Change in flow dynamics

Regulation of flow regime by impoundment

Disruption to river continuity (rivers)

Change in sediment regime (rivers)

Modify or Enhance Structure

Improve Fish Passage

Remove Obsolete Structure

Good Practice Sediment Management

Back to Guidance on selecting mitigation measures