Akbar Kiasalari :

Devastating Flash Floods and Preventing from Its Happening in Future

May 16, 2019

According to the expert officials of the Ministry of Energy, occurrence of heavy and unprecedented spring rainfalls in the first Iranian month of Farvardin in 2016 has been unprecedented in most west and southwest part of the country, the issue of which incurred physical and financial damages to a number of dear fellow countrymen severely.

Introduction:

A look at the past times in Iran and its ancient-historical cities and due to the thickness of alluvium in these areas indicates the occurrence ancient destructive flash floods in these regions and in some cases it has led to the complete destruction of civilization. Although there is no statistics available on the rate of estimation pf ancient flash floods in the country, this has led to the destruction and burial of some human settlements in Iran on a mass of alluvial deposits, some of which have been excavated with ancient archeological discoveries.

On the other hand, thickness of alluvium in some Iranian cities such as Khuzestan plain indicates the occurrence of large flash floods in the past which has led to a significant increase in the thickness of alluvium in these areas. Since any damage [whether environmental or natural resources aspects] has been taken by human for the upstream basins of these areas, naturally, no degradation has been made in terms of vegetation.

Also, any seizure of natural floodways and rivers, construction of building, concrete-based bridges, roads and other buildings had not been formed in the past years. All historical evidences in Iran show that no major flood control has been undertaken by vegetation including pastures and trees.

Also, floodways and rivers have not been able to fully dispose and discharge these destructive and devastating floodwaters.

Accelerating in Completion of Construction of Dam and Implementing Approved Feasibility Studies

Dams under feasibility studies, moreover controlling flood, undertake the role of controlling floodwater, generating electricity, supplying drinking water, industry, agriculture and environment.

Moreover, controlling destructive floodwaters, construction of dam is of paramount importance for the development of industry, agriculture and urban planning.

Storing the water of destructive floodwaters and use of water stored during drought, moreover reducing flood damage, will reduce the damage caused by drought in dry seasons and successive droughts.

Accelerating New Feasibility Studies for Construction of Dam in Upstream of Flood-Hit Populated Areas

For this purpose, it is required to identify high-risk areas from the perspective of destructive floodwater before conducting new feasibility studies. In this regard, accident-prone areas should first be identified. After identifying these regions, feasibility studies should be conducted in upstream basins in order to prevent occurrence of unpleasant events such as the devastating flood happened in the beginning of the current year in 1398 (started March 21, 2019).

Occurrence of Destructive and Devastating Floods in 1st Month of 1395 and 1398

In an article published in 2016, I had pointed to the occurrence of destructive and devastating floodwaters in basin of Khuzestan dams and urged the implementation of feasibility studies projects of passive defense and crisis management and also role of dams in Khuzestan Province to prevent from a large catastrophe. But lack of paying due attention of managers of the country to the viewpoints of expert officials in the field of water crated repetitive and bitter incidents such as devastating flash floods in the first Iranian month of Farvardin (March 21 – April 21).

According to the expert officials of the Ministry of Energy, occurrence of heavy and unprecedented spring rainfalls in the first Iranian month of Farvardin in 2016 has been unprecedented in most west and southwest part of the country, the issue of which incurred physical and financial damages to a number of dear fellow countrymen severely.

The more interesting point that should be mentioned here is this that spring rainfalls in the current year (started March 21, 2019) broke the record the same as in the year 2016. 

This time, more destructive flash floods happened that turned into a national crisis across the nationwide.

Lack of existence of enough dams with considerable tank in storage of water in upstream basin of Gorganroud River caused uncontrolled release of floodwater in Aqqala Plain and its surrounding areas, the issue of which created heavy economic damages to the rural and urban infrastructures.

Although finding the root cause of such unexpected incidents requires carrying out expert-level studies but as the history of this land and territory shows, presenting watershed management strategies and protecting natural resources as well as adopting other structured and non-structured strategies, apart from dam construction, will not control and store this volume of floodwater automatically.

Controlling and Curbing Floodwater in Downstream Side

 Fortunately, a large part of this heavy torrential floodwater soothed and controlled in large reservoirs in rivers of Marun, Karun, Karkheh an Dez. The flash floods were discharged towards sea, lagoons and marches with the controlled release of water. In order to avoid flooding of Dez and Karun rivers and create uncontrolled conditions in dams, controlled release of water from dams was taken into consideration.

Although volume of water was so high that was led to the submerge of several villages and a vast part of roads and fields. But it prevented the occurrence of a larger disaster and full submerge of large cities of Khuzestan Province to a great extent.

It should be noted that dams did not show good performance in controlling and discharging floodwater from themselves. But it prevented from the occurrence of a large disaster and full submerge of large cities in Khuzestan province especially Ahvaz.

It should be noted that dams showed good performance in controlling and discharging floodwater from themselves. Lack of construction of dam led to the submerge of villages and some parts of the cities in downstream sides of dams and plains in Khuzestan province. However, significant damages incurred to some fellow countrymen which is a great sorrow.

Implementation of the below strategies can prevent heavy economic damages to the downstream lands and installations:

Crisis management and integration in the systemic dams,

Identification of risky floodprone areas across the country

Preventing the probable seizure of flooded land areas of rivers in the downstream in drought years by residents and inhabitants,

Lack of construction of recreational sites in floodwater of plain of rivers.

Ready for the occurrence of unprecedented floods in the course of operations of dams,

Dredging natural floodwaters timely,

Drilling and digging artificial floodways around risky points in order to deviate and discharge destructive floodwaters,

Promoting and updating urban disaster management

Training in all public and management levels,

Training in lower levels and schools for raising awareness of people in the face of natural risks,

Therefore, inattention to the aforementioned factors will incur economic damages to a part of downstream villages, each of which plays a leading role in incidence of such accident.

Independent experts of water resources believe that if dams of Dez, Karkheh, Gotvand, Seymareh, Karun 3, Karun 1, etc. had not been constructed, these flash floods would have devoured large cities including Andimeshk, Shush, Dezful, Ahvaz, Abadan, Khorramshahr, etc. completely.

Under such circumstance, all the aforementioned cities were sunken completely.

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