TEHRAN – Throughout history, mankind has always struggled with natural disasters, which are exacerbating over time. In the meantime, the question arises as to how much of Iran's natural disasters are inevitable and how much is the cost of harming the environment?

International Day for Disaster Risk Reduction is observed annually on October 13, aiming to promote a global culture of risk awareness and disaster reduction.

It was designated in 1989, after a call by the United Nations General Assembly for a day to promote a global culture of risk-awareness and disaster reduction. 

The 2021 edition of International Day for Disaster Risk Reduction will focus on “International cooperation for developing countries to reduce their disaster risk and disaster losses”.

Mismanagement and human ownership have caused changes in nature both in national and global dimensions. The Iranian plateau, with its location between two vast expanses of water as well as the intersection of the Eurasian plateau and Saudi Arabia, has always been exposed to numerous natural hazards and disasters. 

Earthquake, as one of the main natural challenges, occasionally becomes the uninvited guest of Iranian homes. On the other hand, the existence of important rivers and water reservoirs in the country has also increased flood risk.

According to UN surveys this year, the main natural disasters listed for Iran are drought, floods, and earthquakes. Subsidence is also a phenomenon that has emerged as one of the consequences of drought along with the aforementioned three challenges.

 Flood, a small price for our oppression of nature

Hossein Rafiei, an expert in the field of water, says: "Natural floods cause destruction when agricultural lands, gardens, and construction are developed in the flood plains." In fact, encroaching on areas that are naturally flood-prone causes floods, so that damages structures and human activities.

Masoud Baqerzadeh Karimi, the director-general of aquatic ecosystems at the Department of Environment (DOE) points to the role of wetlands in flood control and, referring to the unfortunate situation of wetlands, including Anzali Wetland, states that what can be a serious threat to this wetland and surrounding villages in the future is the loss of flood control power.

Floods that flow through 11 rivers into the wetland are stored in a reservoir and gradually enter the sea, but about 80 percent of the reservoir is overflowing due to sediment accumulation and does not have the capacity to hold water, he explained.

Reza Siah-Mansour, a faculty member at the Research Institute of Forests and Rangelands, also pointing to the consequences of changes in forests and says that "when we change the nature of forest lands, we make them vulnerable to water influx." Due to the fact that the forest and rangelands in Iran are often located on slopes, the destruction of vegetation makes them vulnerable to floods, and the soil is washed away by floods bringing irreparable consequences.

The statements of these experts show that the human footprint in intensifying the destructive effects of the flood has become more prominent than before. Over the years and the disappearance of natural barriers that have been at the forefront of flood control, today mankind is more at risk.

Some mismanagements and the feeling of human ownership of nature, have caused changes not only in the national dimension but also in the global dimension, which take a long time to compensate for.

"Climate change is also associated with other devastating weather events such as frequent and more severe storms, floods, rain, and winter storms. Although climate change and global warming may occur as part of natural processes due to fluctuations in sunlight intensity, deviations in the Earth's path and volcanic activity, the climate after the Industrial Revolution and the increasing consumption of fossil fuels is increasingly under the impact of human activities."

Drought and land subsidence 

Today, it is difficult to name an area that does not deal with water problems. These conditions have led to drought as one of the main environmental challenges in Iran. Numerous illegal wells and some poor management decisions, along with global problems such as climate change, have made Iran feel the water crisis more than ever; A crisis that does not end here, and its effects, such as the depletion of groundwater aquifers, introduce us to a new term called subsidence.

Land subsidence, a gradual settling or sudden sinking of the Earth's surface due to subsurface movement of earth materials is mainly caused by aquifer-system compaction, drainage, and decomposition of organic soils, underground mining, oil and gas extraction, hydro compaction, natural compaction, sinkholes, and thawing permafrost.

Subsidence results in significant economic losses in the form of structural damage and high maintenance costs. This affects roads and transportation networks, hydraulic infrastructure, sewage systems, buildings, and foundations. The total damage worldwide is estimated at billions of dollars annually.

Geologists call subsidence a “silent earthquake” because an earthquake is instantaneous and its effects are visible at the same time, but subsidence is the cause of environmental depletion and its impact appears gradually; which is getting a big threat in the country.
Iran is greatly affected by the phenomena, as 29 provinces of the country are affected.

Tehran is the most populous city in West Asia, which is sinking into the ground at an alarming rate.

The metropolis is home to some 15 million people and is a victim of dramatic subsidence. New research reveals that the region is sinking by more than 25 centimeters annually in some parts.

Alireza Shahidi, head of Geological Survey and Mineral Exploration said in May that 80 percent of the groundwater is withdrawn annually in Iran, which outpacing the global rate.

In the whole world, water resources withdrawal is between 3 to 20 percent, and when it reaches 40 to 60 percent which is considered problematic, and it will be a crisis when exceeding 60-80 percent, Shahidi noted.

Over the past decades, some of the aquifer levels dropped by 100 centimeters.

After subsidence, there is practically no way to return, and only by quickly managing excessive withdrawals and blocking unauthorized wells, and developing watershed and aquifer management plans can prevent intensification and continuation.

Although natural disasters and their occurrence are beyond our control, our wrong and unprincipled actions can increase the number and severity of some of them. But without a doubt, the adoption of macro-policies will only affect us sooner or later, taking into account human goals and ignoring the environment.

FB/MG