II. FLOOD LOSS REDUCTION AND REVIEW OF PAST EXPERIENCES
F. Projects as case studies
4. Lessons learned and future needs
The broad lessons that can be deduced from the case studies are that projects are successful when:
- projects face no serious threat from morphological processes in alluvial floodplains (e.g. river erosion);
- there are no severe adverse hydraulic impacts (e.g. higher water level in fluvial environment) and morphologic impacts (e.g. siltation in tidal environment) outside the projects;
- interaction between morphological processes and project intervention is small, and as a result embankments can perform the intended function;
- impact on fisheries is minimal (note: fisheries is a broad based indicator of the project environment);
- irrigation component is present;
- project is accepted by the people.
Evaluations of successful and unsuccessful projects reveal that it is difficult to achieve the economic objectives of the projects without giving due consideration to the environment. Therefore, future planning of flood control projects needs to consider the environmental consequences of the projects in a proper perspective and how such consequences can be mitigated. It has become apparent that economic objectives can no longer be attained at the cost of environment. In this respect planning studies of future flood control projects should cover the following:
- better understanding of the floodplain environment, including hydraulic, morphological and ecological aspects;
- appropriate accounting of environmental consequences;
- round-the-year water management rather than planning only for the flood season; and
- ensuring people's participation.