How can land use planning help reduce flood risks?

The land use plays a central role in reducing flooding and susceptibility to damages.

With increasing human alteration and development of the catchment area, the runoff generation process is changed, especially through decreasing the infiltration capacity of the soil and the change of soil cover. This has lead to concern over the role human alterations of the catchments play in increasing flood hazards. Hydrological responses to rainfall strongly depend on local characteristics of soil, such as water storage capacity and infiltration rates. The type and density of vegetation cover and land-use characteristics are also important to understand hydrologic response to rainfall.
Environmental degradation coupled with uncontrolled urban development in high-risk zones, such as historical inundation plains and at the base of mountain ranges, leads to an increased vulnerability of those communities on the floodplains to catastrophic events. Saturated conditions, or conditions quickly becoming saturated during the rainfall event, inhibit infiltration of rainwater.

Catchment Management taken over the whole catchment area (not only the water system) to optimize the functioning of the catchment can entail a source control approach that seeks to keep as much rainwater retained where it falls so flood peaks can be attenuated. Appropriate planning and regulation of land use can limit the flood damage potential in the areas with flood risks. Further they can be used to prescribe adjustments to existing developments in those areas, e.g. flood proofing or relocation of existing developments.

For more information, please refer to “The Role of Land-use Planning in Flood management“.