Once upon a time some great civilizations grew from the riverbank. Today, the river is no longer considered by people because of several things. Though the river has many functions and benefits which, if managed properly will certainly benefit us. The river can be used optimally if it is adjusted to the characteristics of the river. For example the type of flow, based on the process of formation and even the condition of water stability.
A large flow of water that extends and flows continuously is called a river. The flow of water flows from a high topographic place to a place that has a low topography. The river is a place where rainwater is temporarily accommodated before it empties into the ocean. According to the location of the flow, rivers are divided into 3 types, namely: Rivers that flow entirely on the surface, rivers that flow entirely below the surface of the land such as limestone and rivers, some of which flow at the surface and some below the surface of the land.
According to the stability of the water conditions, rivers are divided into rivers perennial, intermittent and ephemeral.
1. Perennial river is a river with stable or permanent water condition. This river always has enough water even though it is dry. During the dry season, this type of river relies on ground water storage (base flow). The river is found in several countries, including: St. Lawrence, Fraser, Mississippi and tributaries, Red River, Rio Grande (North America) Orinoco Amazon La Plata, Uruguay Rivers (South America) Rhine, Seine, Rhone, Danube, Volga, Don, Ural, Eibe Dniester (Europe) Lena, Yenisey, Amu Darya, Yangstze Kiang, Hwangho, Sikiang, Ganges, Indus, Euphrates, Tigris (Asia) Nile, Niger, Zaire, Volta (Africa)
2. Intermittent or episodic river is a river whose water only exists in the rainy season and when the dry season disappears. In the desert it is known as wadi. Intermittent rivers cease to flow every year or at least twice every five years. Such rivers drain large arid and semi-arid areas, covering approximately a third of the earth’s surface.
3. Ephemeral river is the same river as intermittent only watering during the rainy season but when the rainy season the water discharge is not as large as expected. This type of river absolutely only depends on rain. Ephemeral river flow for very short periods following heavy rainfall or snowmelt. Such rivers are generally found in arid and semi-arid areas specifically near the tropics. Example: Luni and Son rivers (India), Ugab river (Namibia).
The need to know the types of rivers based on the stability of the water to estimate water reserves that will be used to meet daily needs. Each type of river certainly has a different management method so that it can still use water optimally.