The systematic approach to flooding problems

Since 1987 one of the working groups of the International Commission on Irrigation and Drainage (ICID) has, inter alia , been preparing two manuals concerning approaches to flooding problems. The Manual on Non‐Structural Approaches to Flood Management was issued in 1999 while the Manual on the Planning of Structural Approaches to Flood Management has been issued recently (2005). In this paper a broad outline of both manuals is presented. The first manual describes in detail the various planning and response measures in flood management, which are known as non‐structural measures. The latter are measures which alter the exposure of life and property to flooding but do not change the flood(ing) phenomenon as such. The said planning and response measures comprise such actions as floodplain land use management, flood forecasting and warning, flood fighting, flood proofing, etc. It is explained that such measures are sometimes the only ones feasible in the prevailing circumstances and that, moreover, non‐structural measures should always be added to the so‐called structural measures if the latter are considered feasible (i.e. feasible from a technical, economic, socio‐economic and ecological point of view). In the second manual a methodology is presented for the planning of structural measures. This type of measure alters the physical characteristics of the floods and in this connection one must think of the operation of flood storage reservoirs, upstream catchment management, modification to river channels, construction of levees, special flood diversion channels (bypasses) and operation of hydraulics works. The idea behind this methodology is that it is difficult for planners and decision makers to select the appropriate flood protection system for a given situation including a range of possible floods if the problem is not approached in a systematic manner. Copyright © 2006 John Wiley & Sons, Ltd.