Low water is a phase of water regime.
Everyone loves a warm sunny summer. This is a summer vacation at school. Due to the dry warm weather, lovers of “wild” recreation can afford frequent forays into the woods with tents or ashore reservoirs for fishing.
What is the low water period of the river?
Did you happen in hot weather instead of the desired rest on the bank of a raging river to find yourself in a dried up bed? The annual increase in temperature on the planet by one or two degrees leads to a strong temperature drop in the summer. Hot dry climate leads to drying out of small streams and rivulets.
The first to dry up are reservoirs that are fed during the melting of the snow, the rainy season, and not from an underground source.
Speaking to scientific languages, low water is a decrease in the water level in the reservoirs. Most often, this difference is annual and has a certain phase. The system with which changes occur in the water regime is called periods.
The low water period can be short (not more than twenty days) and long (from four weeks or more).The concept of "low water" includes the summer and winter phases.
Dates of summer low water is difficult to determine. Most often the summer low water period is the period from the end of the spring flood to the autumn rains. In early spring, after ice drift and melting of snow, an increase in temperature begins, which, in turn, leads to a decrease in water in the stream.
Drought can only be called a sharp decrease in water in the channel, lasting at least a decade. The short-term period depends on precipitation in the summer. If it starts raining, the river’s water supply is restored.
In the cold season, drought as such is not observed. The winter low water period is the period when the water surface becomes covered with a crust of ice. It can last from late autumn until the beginning of ice drift.
If the river is shallow or has no sources for recharge, stagnation in its basin lasts from four to six months. River flow decreases by an average of 50-70%.
If the water regime of the river depends on the floods, most often it becomes intermittent. The plus of this phenomenon is the increase in the period of river flow and the ability to regulate it.
Rivers and maps
At school geography lessons, each student encountered terrain maps.In addition, we had to memorize the names of rivers, lakes, seas and oceans. Few people know that what we see in the picture in the atlas was also depicted taking into account droughts and freezing.
Low water is a rather inaccurate indicator. After all, annual droughts occur at the same time, but the water level in the channel can be very different. Therefore, it can be noted that these indicators are changeable.
Data on the summer and winter low-water periods are also used in their practice by geodesists and geologists to determine the level of groundwater and the number of sources that feed the river bed. Moreover, thanks to the systematization of information, the rate of change of water in rivers and the period during which water from the source reaches the mouth is estimated.