THE EFFECT OF SNOWFALL ON WATER RESOURCES AND HUMAN LIFE
Prof. Dr. M. Cihan AYDIN
A portion of the Earth’s water mass is constantly undergoing transformation through the hydrological cycle. During this process, an average of 100 cm of precipitation falls on the Earth’s surface each year. This amount may increase due to the effects of global warming. For our country, the average annual precipitation is about 65 cm, which is below the global average.
During the hydrological cycle, water evaporated from the surface of the Earth, lakes, seas, and oceans moves through meteorological processes and returns to the surface as precipitation. Part of this precipitation infiltrates into the ground to recharge groundwater, while another portion flows into rivers, eventually reaching lakes and seas again. This recurring cycle, which occurs naturally every year, provides the clean water resources necessary for drinking, domestic use, and energy—sustaining both human life and that of other living organisms. The same cycle also plays a vital role in purifying polluted water sources.
Although most of the Earth’s surface is covered by water, usable freshwater resources are limited. The amount of usable groundwater and surface water constitutes only about 0.6‰ (six-thousandths) of all the water on Earth. A large portion of this is deep groundwater, which is often uneconomical to extract. Although the remaining usable water seems small, it becomes critically important through the hydrological cycle, serving as the true source of life on Earth.
Within the hydrological cycle, precipitation is the most important stage in terms of clean water resources. Most precipitation falls as rain or snow. The portion of rainfall that becomes surface runoff directly and immediately feeds rivers, making rainfall primarily beneficial during spring months, when it enhances water productivity. During dry periods, however, rainfall is less effective for water replenishment, and sudden downpours can cause floods and damage instead of providing benefits.
On the other hand, snowfall, especially in higher elevations, melts gradually over time and continues to feed water resources throughout the year. Therefore, snowfall in high-altitude regions is a key factor in increasing the efficiency of freshwater resources. In this regard, the Eastern Anatolia Region, often referred to as the “roof of Turkey,” plays a crucial role in the productivity of water resources. The highlands of Eastern Anatolia feed major basins such as the Euphrates–Tigris, Aras, Çoruh, and Lake Van. The snowfall during winter is the primary source of water for these basins.
In addition to meeting needs for irrigation and drinking water, large dams built on these rivers—such as Keban, Karakaya, Atatürk, Deriner, Yusufeli, and Ilısu—supply a significant portion of Turkey’s energy needs through hydroelectric power plants, which are renewable and clean energy sources. Thus, the snowfall in these regions also sustains Turkey’s most important energy facilities.
The area receiving the highest amount of snowfall in both Turkey and Eastern Anatolia is the city center of Bitlis. The precipitation in this area simultaneously feeds both the Euphrates–Tigris and Lake Van basins. For Bitlis, the maximum ground snow load exceeds 1 ton/m². However, according to Turkish standards TS 498 and TS EN 1991-1-3, the officially considered value for Bitlis is only 184 kg/m², which significantly underrepresents the real conditions. In other words, the actual maximum snow load can be 5–6 times higher than the value prescribed by standards.
This poses a serious problem for the region. Because structural systems are not designed according to real snow loads, substantial structural damages occur every year. Authorities must urgently take action and update design snow load standards for this region. Another major hazard is the loss of life and property caused by accumulated snow and ice masses on roofs. Due to improper roof designs, dozens of such accidents happen in the region every year. Attention must also be paid to the risk of avalanches—as tragically demonstrated in 2020, when an avalanche in Bahçesaray, Van, claimed 41 lives.
As can be understood, although snowfall significantly affects our lives during winter months, it is actually the most vital source of freshwater, an indispensable element of life and civilization. Let us remember that if we live in harmony with nature, natural events will cease to be disasters and instead will provide us with the essential needs that ensure our comfort and quality of life.