Watershed Water Definition
What is a water basin?
This is an area where all the waters belonging to the same natural drainage network converge; this is the mouth of a river or tributary at a body of water, such as a lake or sea.
What is a drainage network?
A drainage network is the geomorphological term for the system of rivers, lakes, and underground streams that carry water and sediment. Its morphological configuration is determined by gravity, topography, and river dynamics.
What is the difference between a drainage basin and a watershed?
A drainage basin only includes surface waters, while the watershed also takes groundwater into consideration.
What types of drainage basins are there?
- Exorheic: these flow into large, open bodies of water, like the sea or the ocean.
- Endorheic: they flow into closed bodies of water, such as lakes, lagoons, or salt flats.
- Non-rheic: the waters of these basins are not incorporated into any drainage network because they filter or evaporate before being able to flow out due to the characteristics of the terrain and the climate.
What is basin delimitation?
This is the environmental engineering process through which the boundaries of a drainage basin are defined. This helps calculate the area of the basin, as well as understanding its dynamics. This process of basin demarcation is fundamental for basin planning.
In basin delimitation, the divortium aquarum line (or “division of waters”) is determined; this legal concept establishes regulations in terms of water resources. Each country and region has its own water legislation, but they are all generally aimed at determining the rights and duties of different users and actors, considering water availability, the requirements of those who make use of the resource (domestic, agricultural, or industrial), and the environmental impact.
What is basin planning, and what purpose does it serve?
Basin planning is the set of strategies and actions that are geared toward:
- Conservation of water capital.
- Meeting human needs related to the water resource in an economically, socially, and environmentally sustainable way.
- Regional and sectoral development.
- Efficient, sustainable urbanization.
- Protecting the water quality, preventing pollutants from entering the drainage network.
- Mitigation of the effects of times of drought.
- Prevention and minimization of flood damages.
Basin planning also makes it possible to harness the energy potential of basins. The differences in elevation in a basin can serve to generate hydropower, one of the leading cleanest sources of renewable energy.
Basin planning is essential for achieving Goal 6 of the SDGs (Sustainable Development Goals): clean water and sanitation.
What are the largest watersheds in the world?
The largest water basin in the world is the Amazon Basin. It has an area of more than 7 million square kilometers, and its flow rate is about 200,000 cubic meters per second (approximately 20% of continental freshwaters). It spans 8 countries in South America. It is made up of two systems: a superficial (or fluvial) system – the Amazon River – and an underground one, the Hamza River, probably the longest underground river in the world.
In North America, the largest basin is the Mississippi Basin, which consists of the Mississippi and Missouri Rivers. It is the fourth-largest basin in the world. It covers more than three million square kilometers, its average flow rate is 18,000 cubic meters per second, and it crosses 10 of the 50 states in the United States.
The largest basin in Africa is that of the Congo River, covering almost 4 million square kilometers and nine countries. It has a flow rate of more than 40,000 cubic meters per second, and it is the second-largest basin in the world.
