Non-structural Measures

Structural measures can never completely eliminate the risk of flooding. Nevertheless, because of their physical presence, they have the potential to create a false sense of security, leading to inappropriate land use in the protected areas. Non-structural measures play an important role in reducing not only the catastrophic consequences of residual risks, but also adverse impacts on the environment. Non-structural flood management measures such as land use regulations; flood forecasting and warning; flood proofing; and disaster prevention, preparedness and response mechanisms; have limited environmental consequences and should be actively considered as viable options, both as independent or complementary measures.


Land use regulations

Next to their important role in reducing the risk due to flooding land use regulations can contribute substantially to environmental preservation. For example certain land use regulations can lead to the reduction of surface runoff as well as to the conservation of ecosystems. Furthermore floodplain zoning can regulate the location of polluting industries and sewage treatment plants, thus preventing the dispersion of hazardous substantials due to flooding.


Flood forecasting and warning

Of all non-structural measures, flood forecasting and warning is the most widely accepted and has been used since the latter half of the 20th century. Flood forecasting allows concerned people and authorities to take preventive and emergency measures. Authorities can respond appropriately with dam operations, opening and closing the gates of various flood management structures, anticipatory releases to increase reservoir storage capacity, etc. Moreover hazardous material can be brought away from the affected area, thus preventing environmental damages.


Flood proofing

Flood proofing, a combination of long-term, non-structural and minor structural measures, as well as emergency actions, is important not only in reducing damage due to flooding, but also in preventing the negative impacts on the environment such as the spread of pollutants. It includes provision of quick drainage facilities such as the cleaning of primary and secondary drainage channels and clogged cross-drainage works before the onset of the flooding season. Moreover flood proofing measures include removing goods, equipment and harmful industrial, agricultural and domestic chemicals, beyond the area subject to flooding or out of contact with flood waters, by constructing high ground or small embankments.


Emergency preparedness, response and recovery

The awareness of the community at risk of flooding should be raised and maintained, with a clear understanding of their role in responding to emergency situations appropriately. This is critical in organizing coordinated evacuation from the affected area, maintaining healthy and hygienic conditions and preventing environmental pollution in the flooded areas. Flood-prone populations should be dissuaded from storing harmful chemicals during the flood season, made aware of likely pollutants in flood waters and advised of the ways to avoid their adverse impacts.

After a flood, the cleaning operations are undertaken at an emergency level and little attention may be paid to the dumping of rubbish and debris. If not planned in advance, it may end up in drainage channels, ponds, wetlands or rivers, impacting the natural ecosystems.

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