EghtesadOnline: Timely and effective flood mitigation strategies help in saving precious lives and minimizing material loss, director of the National Water and Wastewater Engineering Company of Iran (Abfa) said.
“Floods, the deadliest, costliest and most common form of natural disaster, are not always easy to predict. This means all contingencies must be in place at all times,” Qassem Taqizadeh Khamesi was quoted as saying by ILNA.
Taking specific measures namely building dams (if necessary), developing watershed management techniques and river dredging are among key strategies not to tag floods as “unexpected events” anymore, Financial Tribune quoted him as saying.
Despite the fact that dams, seawalls, floodgates and levees are important in containing floodwaters, these cannot always deliver as they have their own problems and constraints, but “we still need them,” he added.
Unlike senior officials, namely Energy Minister Reza Ardakanian and Khamesi, experts in other countries say dams are a legacy of the past and counter-productive to managing floods and induce a false sense of security. Furthermore, they leave behind a long trail of long and short term ecological destruction.
Although dams and levees help make floods less frequent, they can actually make floods more catastrophic when the deluge comes. That is because when they overflow (like in Sistan-Baluchestan Province last week), downstream areas must be emptied to save lives.
Heavy rainfall, which started 10 days ago, caused flash flooding in the southeastern provinces of Sistan-Baluchestan, Kerman and Hormozgan. It was Sistan-Baluchestan that bore the brunt as its southern areas received 26 times more rain than last year.
The Abfa official says humans have increased the risk of death and damage by rapid urbanization, building homes, businesses and infrastructure in vulnerable flood-prone areas like river basins.
To try to mitigate the risk, governments in many countries order residents in these areas to buy flood insurance policies (if they cannot leave the area) and announce construction requirements aimed at making buildings more flood resistant. Such measures have never been taken seriously in Iran, so far.
Referring to other mitigation measures, he noted that watershed management has been neglected in many regions not only due to financial constraints but also the failure to conduct studies based on specific needs of each region.
Geography determines whether dams need to be built or other techniques like watershed management should be applied.
A watershed is the geographic area through which water flows across the land and drains into a common body of water, whether a stream, river, lake, or ocean.
Watershed management is important as it helps protect and improve the quality of water and other natural resources within a watershed by managing the use of those land and water resources in a comprehensive manner, he noted.
Highlighting other ways to control floods, Khamesi added that river dredging does diminish some of the associated risks. Dredging is crucial to preserving the natural flow of a river and reduces the potential of a likely disaster from occurring in cities that are prone to reoccurring flooding during rainy seasons.
He said dredged channels require long term maintenance and continued work as new silt accumulates in the river bed over time.
The overall aim of most dredging activities is to reduce the extent of flooding and act as a flood management tool. However, understanding the extent to which dredging can mitigate flood risk and flooding can be difficult because of differences between location and river system hydrology and ecology, which can influence the outcome.
There are many disruptive effects of flooding on human settlements and economic activities. However, flooding can bring benefits, such as making soil more fertile and providing nutrients in which it is deficient.
Periodic flooding was seen as essential to the well-being of ancient communities along the Tigris-Euphrates Rivers, the Nile River and the Indus River among others.
The viability for hydrologically based renewable sources of energy is higher in flood-prone regions like Khuzestan Province in Iran.