Mode means order, control. This term is used to denote order in many areas of human activity, as well as in the nature around us. One example of this is the river regime. But if in everyday life a person adheres to a certain routine, then in the regime of a river, he more often takes an observational position - states the fluctuations that occur in the life of the river, and only in some cases can intervene in the regime of the watercourse in order to change it.
Any object of the surrounding world can be described by giving it a characteristic. Including a characteristic is given to surface water bodies - oceans, seas, lakes, rivers, swamps. This characteristic is called hydrological. It necessarily includes the hydrological regime of the river - a set of characteristic features that change the state of the river over time.
The hydrological regime is manifested in daily, seasonal and long-term fluctuations in water levels and water content(together this constitutes the water regime), ice phenomena, water temperatures, the amount of suspension in the stream, water hydrochemistry, changes in the riverbed, flow rates, waves and other phenomena and processes that occur continuously in the life of the river. All of the above and other elements of the hydrological regime together determine the regime of the river.
Depending on whether or not there is a hydraulic structure on the river that can influence the hydrological regime, rivers have a regulated regime or a natural (domestic) regime. Of all the elements of the river regime, river runoff is of great practical importance. Its value determines the watering of the territory, territorial hydropower reserves, the size of waterways in this territory.
The river regime depends on many factors: climate, land relief, water supply and others. The main factor is water supply. The rivers are fed from atmospheric precipitation in the course of the water cycle in nature. The waters supplying food to the rivers are divided into glacial, snow, rain and underground. The same terms are used when defining the types of river feeding. In some cases, it is difficult to clearly define the dominance of any one source of river feeding (river feeding type) and then the term “mixed feeding type” is used.
Phases (periods) of the water regime are divided into high water, low water and floods according to characteristic features. The flood occurs annually in a certain season of the year, is marked by a long rise in the level with high marks and the largest water content in comparison withother phases. Low water is also seasonal in nature and is characterized by a low level and the least water content; at this time, the river is fed mainly by groundwater. Floods are characterized by rapid and short-term high levels with a large flow of water; they occur as a result of rains, snowmelt.
Characteristics of the Nile River: the length of the river with the rivers forming it in the Rukakara-Kager-Nile river system is 6852 km - this is the second longest of the Earth's rivers. The Nile flows from south to north towards the Mediterranean Sea. The course of the river is stormy in the upper and middle parts, slow in the lower part; to the mouth of the Nile is divided into numerous branches and near the Mediterranean Sea forms the greatest delta. The Nile is the source of life in the desert Sahara. Almost the entire population of Egypt (97%) settled along its coast. The permanent flow of the Nile is provided by year-round equatorial rains (the Blue Nile catchment area) and rains in the southern regions (the White Nile catchment area), and rains in the Abyssinian highlands, washing away loose soils. The river flow carries suspensions, depositing nutrient silt in the delta, on the fields of which the Egyptians harvest up to 3 times a year. To combat floods, in which the level of river water in the Cairo region rose by 8 m, which threatened disaster for the population, the famous Aswan Dam was built. And now the regime of the Nile River in the lower reaches is regulated. But although the Nile is 3 times longer than the Volga, in its channel it carries a volume of water 2 times less.
