What is the fall of the river and its regime? The slope and fall of the world's largest rivers

The fall and regime of the river are key hydrological parameters. From them one can form an idea of the water content, the nature and speed of the flow of a particular watercourse. What is the fall of the river? How correctly to calculate its bias? What determines the regime of a particular river? The answers to all these questions will be considered in our article.

Hydrology and relief

Each river is unique. It is very difficult to find in nature two watercourses, which will be absolutely identical. They differ in length, water content, chemical composition of water, regime, and so on.

The nature and speed of the flow of the river largely depends on the terrain in which it flows. In the mountains you can see some watercourses, and on the plains - very different. Mountain streams carry their water quickly and swiftly. Their channels are stony and full of rapids, waterfalls. Floods often occur on such rivers. Some of them have catastrophic consequences.

Plain rivers, on the contrary, are calm and measured. Their channels are smoothly bent and often have solid depths. The flow velocity is then minimal.

The fall of the river and the bias are precisely those indicators by which it is possible to determine the type of channel processes of the watercourse. How to calculate them will be discussed later.

The fall of the river and the bias - what is it?

All the watercourses on our planet flow from top to bottom, according to the law of universal gravitation. The point of the beginning of the watercourse is called its source, and the final one is called the mouth. What is the fall of the river? What is usually called its bias?

The fall of the river is the difference in meters between the height of its source and the height of the mouth. A slope is the ratio of the fall to the length of the watercourse. This parameter can be expressed in percent, ppm, degrees or in m / km.

Slope of lowland rivers, as a rule, does not exceed 0.1-0.2 m / km (or 10-20 ppm). For mountain streams this indicator can be tens or even hundreds of times higher. On some segments, it can reach several tens of meters per kilometer. Similar sites are a series of cascades and waterfalls.

The slope of the watercourse can be longitudinal or transverse, when the channel is skewed horizontally.

How to calculate the slope and fall of the watercourse?

So, what is the fall of the river and its deviation, we determined. It remains to find out how these figures are calculated.

Calculate the fall and slope of the river is very simple. For this it is necessary to know only three values: the total length of the watercourse, the height of its source and mouth. Having learned the difference in height (absolute) between the last two points, we get the value of the fall. If the river falls into the sea or the ocean, then the absolute height of its mouth should be considered a mark of 0 meters. The slope of the river is calculated as follows: the value of the fall should be divided by the total length of the watercourse.

Suppose that the length of the river "X" is 800 km. Its source is at an altitude of 1450 m, and the mouth is at 650 m. The fall of the given river is: 1450 m - 650 m = 800 m. From this it follows that the slope will be equal to: 800 m / 800 km = 1 m / km (or 100 ppm).

The regime of the river and the factors that determine it

Under the regime of the river is understood the whole complex of changes in its state, conditioned by the geography and climate of a particular locality. These changes can be diurnal or seasonal. The regime of the river is manifested in fluctuations in temperature, flow and water level in the riverbed.

The three main phases of the water regime of watercourses include meadow, high water and floods. Flood is the period of increase in the water content of the river and the maximum water level in its channel. Flooding is a sharp and rapid increase in the water level in rivers caused by heavy rainfall. Mezhen - this is the minimum water level in the channel of the watercourse (this phase of the water regime is illustrated below in the photo).

The phases of the river's water regime (except for floods) are consistently repeated in the same season of the year.

The water regime of the river depends on many factors of the environment. First of all it is:

• Geographic location of the region;
• Climatic conditions;
• Nature of supply of the river;
• Relief and vegetation;
• The presence of a change of seasons;
• Anthropogenic factors.

Fall and slope of the largest rivers of the Earth

Below are the values of the slope and fall of the ten largest river systems of our planet:

Finally

What is the fall of the river? This is the difference in height between the source and the mouth of a particular watercourse. The slope of the river is the ratio of the fall to its total extent. Based on these two parameters, we can conclude on the nature, as well as the speed of the flow of a particular river.