Torrential floods have hit Kerman Province twice in the past 20 days, overflowing their banks and inundating residential areas, especially in rural regions, deputy governor for civil affairs said.
“Kerman has more than 40,000 kilometers of rivers, of which 8,000 km are in critical conditions and need to be dredged,” Mostafa Ayatollah Mousavi was also quoted as saying by IRNA.
According to the official, measures have been taken in recent years to tackle the issue. Rivers and canals have been dredged in deluge-prone regions to prevent and reduce floodwater damage, although there is much left to be done.
“We have so far dredged 132 km of the province's rivers. If the government had not done so, we would have lost several lives in recent floods,” he said.
“Dredging these rivers requires $640 million of credit, which is equivalent to the budget allocated to the province in five years.”
Majid Saeedi, director general of the Governorate’s Crisis Management Office, said recent floods have inflicted losses worth $80 million on Kerman Province’s agriculture sector and infrastructures.
“Nineteen cities of the province were hit by natural disasters earlier this month. Losses incurred by the agriculture sector and infrastructures are estimated to reach $33 million and $47 million, respectively,” he said.
“Due to the failure of some nomads in heeding warnings related to the timely evacuation of pastures, Hamoun-e Jazmurian in particular, as many as 1,407 head of livestock were killed. A total of 1,907 homes in urban and rural areas were also damaged, of which 450 units must be demolished and renovated, and the rest need repair.”
Need for Dredging
Dredging covers a range of activities from the removal of material from the bed and sides of river channels through to the straightening (canalization) and/or deepening of watercourses.
There is no denying the fact that flooding has shaped rivers and landscapes for millennia in Iran, but because its power has been underestimated, houses, possessions, businesses and land have been lost to floodwater in the past, especially in Golestan, Lorestan and Khuzestan provinces.
According to the Energy Ministry, although dredging is not the best long-term and economically-viable solution, it has helped prevent flood damage to some degree.
Dredging of a reach (length of channel) leads to a reduction in water levels and a reduction in fluvial flood frequency in the immediate area.
Last year, $20 million were allocated for river engineering, which showed a threefold increase compared to the previous year’s spending.
River engineering helps optimize rivers’ numerous benefits while providing protection against flooding.
Although dredging can play an important role in flood risk management in some cases, a number of experts believe that it is not a “standalone solution” as it has its own negative effects.
Drawbacks and Disadvantages
Dredging can have significant direct and indirect drawbacks for ecosystems. For example, it can lead to loss and degradation of natural habitats, pools and riffles. It can also impact a range of protected species.
The removal of vegetation from within channels and along channel banks during dredging operations can increase water temperature by reducing shade. Warmer temperatures result in lower oxygen concentrations, making fish and invertebrates in dredged channels more vulnerable to stress during hot weather.
In a nutshell, 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.
Despite the fact that clearing the bed of a harbor, river, or other areas of water as well as building dams, seawalls, floodgates and levees are important in containing floodwaters, these cannot always serve the purpose effectively as they have their own constraints. Nevertheless, they are still needed.
