Sudden rise in water level in the river: when this happens

The amount of water in the reservoirs is not the same throughout the year. Sometimes there is a sudden rise in the water level in the river or its significant decrease. For example, the flat river arteries of temperate latitudes are full in the spring during the rapid melting of snows, when the channels are unable to contain rapidly flowing water and flood, flooding the floodplain.

This phenomenon is called flood, but it is not the only one that causes significant fluctuations in the height of the water. After abnormal rainfall, a sudden sudden rise in the water level in the river is recorded. This flood is called a flood, and its consequences are flooding. Let's talk about how these phenomena differ and how they arise in this article.

Flooding

A pronounced and seasonally recurring flood of rivers, called flood, is a consequence of the natural process of rapid thawing of the snows. This is a very long-lasting action. It causes a significant increase in water in the river, which usually provokes a way out of the habitual channel and the flooding of nearby floodplain meadows. By and large, this phenomenon can not be regarded as a sudden rise in the water level in the river, since such a situation is always predictable, but this state differs from the usual one. At the time of high water, the lion's share of the total volume of the annual flow is from 50 to 80%.

Seasonality of the phenomenon depends on the characteristics of the waterway, its nutrition and the terrain where it flows. So, the spring high water is inherent in most of the plains water with snow feeding. A clear demonstration of these are rivers flowing among coniferous and mixed forests of the plains of Russia. They are dominated by the snow food, and since the peak melting of ice occurs at the beginning of April, then the flood comes at the same time. Mountain is more often spilled in summer, because at this time, active melting of glaciers begins , causing a sudden rise in the water level in the river. Summer floods are also observed on rivers with rain feeding in the Far Eastern monsoon climatic zones with characteristic dry winter and rainy summer.

The process of increasing water is uneven: in the first few days it arrives slowly, then accelerates, often reaching 0.3-0.6 meters per day. The rise of water in small and medium rivers can be 2-4 m, on large waterways - up to 20 m. Often even from the expected arrival of water, very serious consequences are caused by large-scale spills.

In a word, the sudden rise in the water level in the river caused by the flood is natural, and its seasonality is explained by the peculiarities of the natural zone where the river flows.

Flood duration

On small reservoirs, the water level returns to normal after 20-30 days. The highest point of the rise in water reaches them at the end of the first week. On large navigable rivers, the duration of the flood is 2-3 months, and the peak of the maximum rise is fixed for 20-30 days.

In contrast, an increase in the level falls several times longer. Spring flood is usually accompanied by an ice drift, the duration of which varies from 5 to 15 days.

Sudden rise in the water level in the river, provoked by the flood

A phenomenon of a completely different order is considered to be flood, the occurrence of which can not be predicted. Here, neither the seasonality, nor the periodicity, nor the regularity are involved, as it is impossible to envisage a spontaneous event. Flooding represents the consequences of the elements, resulting in a sudden short-term rise in the water level in the river. Flooding occurs at very different times of the year. It is absolutely not dependent on river life processes and can be provoked by abnormal weather conditions - abundant rains, snowmelt, etc.

For example, monsoon rains in India and Pakistan cause river spills several times a year. The duration of the flood varies from 2-3 hours to 3-7 days.

Flood

The sudden rise in the water level, which is natural or unexpected in the river, causes consequences, which are called flooding. It manifests itself in floods of rivers, flooding of the terrain and depends only on the size of the flood or high water. The rise in water caused by the flood is classified in different ways. Here the decisive importance is the degree of expectation or randomness of the occurred phenomenon.