What is the fall of the river and its regime? The slope and fall of the largest rivers of the planet

The fall and river regime are key hydrological parameters. Using them, one can get an idea of ​​the water content, nature and speed of a particular watercourse. What is a river fall ? How to calculate its bias? What determines the regime of a particular river? We will consider the answers to all these questions in our article.

Hydrology and terrain

Each river is unique. It is very difficult to find two streams in nature that will be exactly the same. They differ from each other in length, water content, chemical composition of water, regimen and so on.

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

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

The fall of the river and the slope 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.

River fall and slope - what is it?

All streams 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 end - the mouth. What is a river fall? What is called its bias?

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

The slope of the flat rivers, as a rule, does not exceed 0.1-0.2 m / km (or 10-20 ppm). For mountain streams, this figure can be tens or even hundreds of times higher. On some sections, it can reach several tens of meters per kilometer. Such sites are a series of cascades and waterfalls.

The slope of the watercourse can be longitudinal or transverse, when there is a horizontal skew of the channel.

How to calculate the slope and fall of the watercourse?

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

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

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

River regime and factors determining it

Under the regime of the river is understood the whole complex of changes in its condition, due to the geography and climate of a particular area. These changes may be daily or seasonal. The river regime is manifested in fluctuations in temperature, flow and water level in the channel.

The three main phases of the water regime of watercourses include low water, high water and floods. High water is a period of increase in river water content and maximum water level in its channel. High water is a sharp and rapid increase in river water levels due to heavy rainfall. Low water 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 water regime of the river (except for floods) are stably repeated in the same season of the year.

The water regime of the river depends on many environmental factors. First of all, these are:

• geographical location of the region;
• climatic conditions;
• the nature of the river;
• relief and vegetation;
• the presence of a change of seasons;
• anthropogenic factors.

The fall and slope of the largest rivers of the Earth

Below are the slopes and falls of the ten largest river systems on our planet:

Finally

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