9. How can floods be prevented?

There are many ways of preventing floods, which, if implemented holistically, can lead to a reduction in their occurrence.

Flood prevention can be implemented at the following levels:

  • World level – through environmental protection, addressing climate change and through development of forecasting and prediction systems;
  • Regional level – through the establishment of prevention systems and prediction and early-warning systems for flood risks, such as implemented after the tsunami in the Indian Ocean. It was due to an undersea earthquake (M = 9.1)  which struck Indonesian Island of Sumatra killing at least 225,000 people across a dozen countries in December 2004;
  • National level – through the development and implementation of a national policy for combating disasters and, in particular, floods;
  • Local level – through the implementation of a range of measures: development and maintenance of the respective plans for protection, control and activities designed to prevent floods and reduce their impact, construction and maintenance of hydraulic installations, etc. As concerns hydraulic structure, for instance, in the northern and central Apennnes (Italy) since several decades, flow regulation devices were constructed in areas adjacent to the courses of some rivers (Parma, Enza, Secchia, Panaro, Arno, Tevere and others) in order to control the hydrological hazard of riverine floods. These structures (named “Flow regulation systems”) consist principally of a regulating dam built across the riverbed and a storage basin bordered by embankments. Their most important function is to reduce the flood peak, that is, they intervene on only a limited scale (Fig. 9).
  • Measures for personal protection which should include school training, cultivation of individual awareness of the existence of a flood risk in the places where people live or stay as tourists, knowledge of the steps to be taken both during and after flooding and a minimum of first aid skills, etc.
Fig. 9. Flow regulation system of the Secchia River, located to the West of Modena, during the 13 May 2019 flood peak. It shows Secchia River flows from right to left. In the centre stands the regulating dam built across the riverbed and on the right side, the  storage basin bordered by embankments (From a video of Marco Amendola).