An estuary is a funnel-shaped mouth of a river with one branch, expanding closer to the sea. When sediment - earth and sand brought by wind or water - is removed either by sea currents or tides, and the part of the sea adjacent to the place is deeper, an estuary is formed. The Yenisei, Don and many other rivers have estuary-shaped mouths. The opposite concept of the estuary in geography is the delta. This is the mouth of the river, divided into streams. The Nile, the Amazon and the Volga have such a part of the water flow, but the latter, in turn, forms an estuary when it flows into the Caspian Sea.
How does an estuary appear?
Usually, a river estuary is the result of submersion of one of the sections of the coast of the watercourse. This process is accompanied by flooding of its lower part. The tides have a strong effect on the estuary, as a result of which saline (ocean and sea) as well as fresh (river) waters enter the riverbed. Tides often occur with such force that the flow of the stream turns back, and s alt and fresh waterpenetrate many kilometers deep into the earth. If such a tide hits a rather narrow V-shaped estuary with very steep and high banks, the water level can rise so much that a huge wave called a bore is formed. In this case, he will penetrate deep into the earth until he completely spends all his energy.
Largest estuaries
The estuary is a place convenient for navigation, as it is protected from all sides. In many areas, there are even quite large cities. For example, Lisbon is located on the estuary of the Tagus River.
The world's largest site of this type is called La Plata. It is located between the countries of Uruguay and Argentina. There, rivers such as Paraguay and Parana flow into the sea. It is on the banks of the La Plata estuary that the cities of Montevideo and Buenos Aires are located.
Climatic conditions
Estuary is a place where the climate is very stable and rarely "pleases" with new and unexpected precipitation. For example, the monsoonal pattern may most often prevail. It represents constant tropical winds. As a rule, they go from the land side in summer, and from the sea in winter. Summer in such conditions is somewhat cool - about 15 degrees. And also the described climatic conditions make it clear that an estuary is a site that can constantly be fed by rain waters. An example of such a territory is the Gulf of St. Lawrence. It is constantly visited by tourists and can always please with its landscapes.
