Water is one of the most important components of our life. Speaking about water, one should not forget about such a thing as water balance. Let's start with the definition.
Water balance - the ratio of the arrival, changes in the supply of water and its consumption in a certain period of time. It takes into account all the water on Earth in a liquid, gaseous, and solid state. For land (which has runoff into the ocean), evaporation is numerically equal to the quantitative value of precipitation, if we subtract river and underground runoff from them. And for the oceans - the sum of precipitation, river flow and groundwater inflow from the continents. If we talk about closed (drainless) land and about the whole Earth as a whole, then the evaporation is correlated with precipitation.
This is a very important indicator, therefore a special equation is derived for it, which calculates the water balance used for carrying out the balance assessment. In this way, the volumes of renewable water resources in vast territories remaining as a result of the water cycle in nature are calculated. Also, this indicator is determined for lakes, rivers, oceans and soil.
The water balance of the lake is determined based on the influx of atmospheric precipitation, groundwater and surface water, taking into account changes in the water level in the lake in the time interval of interest. According to the same principle, the water balance of reservoirs is calculated. The use of river, lake and groundwater for water supply to the population and industry, irrigation of plants significantly changes the ratio of water balance and its elements. Its calculation is also necessary for the implementation of many practical actions: forecasting water inflow into mines, quarries, designing and working on measures to manage the water regime. In many respects, the long-term and seasonal fluctuations affect the water balance, but even more - changes as a result of human activity. Elements of water balance are measured at hydrometeorological and hydrogeological stations.
There is also such a thing as a water management balance - the ratio between the income and consumption of water on a certain part of the earth’s surface for an interesting period of time when taking into account human economic activity. This indicator helps to analyze and assess the water availability of the basin. In the event that the balance has a negative indicator, we are talking about the need for measures to cover the water deficit.
Water balance of the soil is a proportional ratio of the amount of water that enters the soil, and that which is consumed from it for a certain period of time. It is calculated, if necessary, to find out the water supply level of local plants. Depending on the ratio of the measured variables, the mode is defined as:
- permafrost;
- flushing;
- periodically flushing;
- non-flushing;
- effusion;
- irrigation.
The concept of "water balance" is also used to assess the state of the human body, namely the water content in the blood and cells. This is a very important indicator, a person’s normal state of health, metabolic rate and absorption of beneficial substances depend on it.
