The movement of water in the river is caused by the fact that height of its source and the mouth is not identical. The mouth and a source have different marks in relation to sea level. Usually count full falling and on some site of the course. These data are necessary at design and construction of dams, planning of transport and tourist routes.
It is required to you
- - physical map of a river basin;
- - GPS navigator;
- - tools for measurement of distances;
- - calculator.
Instruction
1. Define falling of the large Po River to the card. On physical maps marks of a source and the mouth usually are affixed. The first will always be more the second. At the mountain rivers a difference usually very big. Those which make all the way on the flat plain can have it not so considerable, but all the same is. Subtract a mouth mark from a source mark. It will also be full falling of the river.
2. Sometimes it is required to define falling of the river between two points of its course which are not the mouth and a source. The algorithm of calculations will be the same, as in the first case. Find the necessary marks in the card and subtract smaller from bigger value.
3. Falling of the small river or a stream can be determined without card, by the GPS navigator. Choose clear day and walk to a source. Determine its height above sea level. In the same way measure mouth height. Carry out necessary calculations. Calculate falling on the certain site. As a rule, it is measured on course kilometer. At the flat rivers value usually small therefore consider it in centimeters on kilometer. At the mountain rivers the difference of heights even on very small site of the course can reach several meters. Actually in this case you calculate not only falling, but also a river bias on the site in 1 km.
4. Knowing falling, you can calculate a bias. For this purpose you need to measure still the extent of all course or certain site. On the map the scale is always designated. Measure river length by a ruler or compasses measuring instrument and increase by the number of kilometers which is the share of 1 cm. Then divide decline of the river by the received distance. The bias most often as a percentage, but maybe in per mille, and in angular degrees is calculated (as a rule, for the mountain rivers).