The importance of snow cover in the process of river recharge

Snow powder… A bane for some, a joy for others. But regardless of our attitude to this form of precipitation, it is worth knowing that these billions of unique flakes are of great importance to nature, to industry, to agriculture, to us humans, to the world.

Everyone knows that water is the main component of all living organisms and that it plays a very important role in the human body. It is elementary, without it there is no life. And I mean that literally. It is assumed that without food a person can survive about 14 – 21 days, while without water the value is about 7. Virtually all of us have access to water in sufficient quantity and quality. And with households almost completely supplied with mains water, its availability at the “tap” at any time of the day or night, seems to be a given. We take for granted that it will always be there, and the summer droughts that are occurring with increasing frequency do not force everyone to save it. And also most people equate drought only with summer, high temperatures and a deficit in precipitation. Meanwhile, snow droughts, or periods of unusually low snow cover for the season, are becoming more common. So much for those smaller snowfalls across the country or snow occurring only in the mountains, we shouldn’t be happy at all.

How important is snow? Very! It is estimated that the volume of water in the form of snow, ice and glaciers on Earth is 24,064,000 ^km3, which is 1.74% of the total amount of water. But in terms of freshwater resources on our globe, it already accounts for about 69%.

Snow cover is an important source of fresh water on Earth. Meltdowns each year account for half of the world’s freshwater supplies, and up to 75 percent in the case of western areas of the US. Snow also plays a huge role in our country. This is because Polish rivers are fed by rainwater and water from melting snow cover. Poland’s water resources are small compared to other European countries, amounting to about 60 ^km3. However, they can vary – in a very dry year they are smaller than 40 ^km3, while in a very wet year they are larger than 90 ^km3. They are characterized by high seasonal variability and uneven spatial distribution. More than 70% of Poland’s water resources are surface water, while less than 30% are groundwater. And that’s where our tap water comes from.

Studies show that the amount of water flowing in a river depends largely on how much precipitation comes in the form of snow.

Snow accumulates in the cold winter months, forming a snow cover that thaws in spring and early summer. In a short period of time, during the melting of the snow cover, the channel of the watercourse is fed with a large amount of water. Meltwaters create water sources that then feed streams, rivers and lakes on their way to the sea. Snow cover supports entire ecosystems as snowmelt water flows from mountain streams into rivers, lakes and coastal areas. It can be said that snow is a winter free retention reservoir with a huge volume. Citing the National Snow and Ice Data Center, 40 million people in the United States are supplied with water from the Colorado River, whose supplies are stored in several reservoirs for this purpose. However, it should be noted that for the upper Colorado River basin, the most important “reservoir” is the snow cover. In addition, the potential for storing water in the form of snow in the mountains is much greater than in all other reservoirs on the river.

Lying on the earth’s surface is a huge amount of fresh water. They are not available immediately, you have to wait until they melt and get into the rivers. However, when it comes to snowmelt, the pace is important. The gradual, slow thawing of the snowpack provides nature with water at a “reasonable” rate when it is needed most. The water content of the soil is also increased – a supply to be used in the spring. During this time, natural aquifers and man-made reservoirs are also replenished. So, a little snowfall will translate into low water content in the soil, resulting in agricultural drought, and this, combined with the lack of rainfall in the summer, will translate into a shortage of much-needed water for plants. It should also be emphasized that a rainy winter, but without snowfall, will not provide a sufficient supply of water, as the water will quickly drain from the ecosystems. Also, the rapid melting of snow due to a significant increase in temperature is not beneficial, as it causes water to run off quickly into rivers without having time to infiltrate. In addition, it can generate flood risks. Earlier, faster snow melt will affect the drying up of rivers in late summer, but also greater evaporation from soil exposed too early.

The drought that occurs during the summer is not just about reduced yields. This consequently means less water flowing in rivers, and thus less water available to us for our daily purposes. During the summer, some rivers, as a result of the lack of supply in the form of precipitation, high temperatures, and thus intense evaporation, being fed only by groundwater (which will also not be replenished by winter snowmelt), will dry up in places. Water deficits may occur throughout the country, but central and western Poland, including Greater Poland, is most vulnerable to drought. One factor influencing this, in addition to the existing disparity between precipitation and evaporation, is the increasingly frequent occurrence of snowless winters. The aforementioned snow droughts, which occur especially in areas characterized by recharge coming mainly from snow cover, result in less water being delivered to the region in the form of snow or rain.

In conclusion, snowfall is crucial for a regulated and secure free economy.