Italy is a country with many lakes. Many of these, especially in the alpine and pre-alpine regions, have a glacial origin. They were excavated from the ancient glaciers that once covered these areas. Not all Italian lakes, though, were created this way. Many of these, in fact, did not originate naturally: Our Country, in fact, has many artificial lakes. Some of these are artificial reservoirs with nothing in common with artificial lakes. Others are a real paradise for the fauna: lakes like the Sila ones, for example, have now become indispensable for herons and coots. Lake Salto is now a natural habitat for chubs, trouts and carps. Lake Barcis, in the Italian region "Friuli-Venezia-Giulia", is a place for canoeists, just like the Brasimone one, in the other Italian region, Emilia Romagna. But why have artificial lakes been built in the past decades and centuries? And why are they still built today?
Why does Man build artificial lakes? If constructing buildings, bridges and tunnels may be something obvious, building artificial lakes is not so much so. The origin of these water surfaces, born in areas previously occupied by pastures, forests or little villages, has many reasons.
The majority of artificial lakes were built to generate electricity. Collecting water from large artificial basins - filled with the waters of nearby rivers and torrents - can in fact regulate the water level, exploiting the kinetic energy as the water falls downwards.
Other times, artificial lakes were built to store water for agricultural purposes, to guarantee water supply, in time, and irrigate the land. An artificial lake, in certain environments, can be used for naturalistic purposes, like the creation of bird habitats. Other smaller artificial lakes, with reduced dimensions, have also been built with an aesthetic purpose in mind, especially in parks, but also sports fishing purposes.
But which are the world's largest artificial lakes? And which are Italy' largest ones?
There are two different ways to show the dimensions of artificial lakes: It is possible to think in terms of area or in terms of volume volume. The ranking of the world's largest artificial lakes can vary greatly, therefore, according to their average depth.
The artificial lake with the largest area is Lake Volta. This huge bed of water covers 8,805 km2, 3.5% of Ghana's territory (just consider that the largest Italian lake, Lake Garda, only touches 368 km2). The Akosombo dam, completed in 1966, blocked the Volta River, creating this huge water basin. Lake Volta, though, was created at the expense of many people: 76,000 residents had to, in fact, move from their lands. It was built to irrigate the land, for farming purposes and for fishing. Smallwood is the world's second largest artificial lake. It covers an area of 6,527 km2. This Canadian based basin, located between Terranova and Labrador, includes 88 dams.
Lake Kariba is the world's largest artificial lake according to volume. Located between Zambia and Zimbabwe it includes 180 km3 of water on an area of 5,500 km2. The lake took shape after a double-arched concrete dam was built on the Zambezi River, the first project to be funded by the World Bank in the African continent. Works to build the dam began in 1956 to end 4 years later. They were finished 6 months ahead of schedule and built by an Italian consortium with companies that many years later merged into Salini Impregilo. The Bratsk Reservoir is the world's second largest artificial lake according to volume. Located in Russia, it was formed after the huge dam on the Angara River was built. It's volume totals 169.3 km3.
The largest Italian artificial lake, although small when compared with the world's largest, is Lake Omodeo, in Sardegna. This basin has a volume of 0.792 km3 and extends over a 30 km2 area. It is formed by blocking the course of the Tirso River. The first dam that gave birth (so to speak) to this lake, was built between 1918 and 1924. It was designed by the Italian engineer, Angelo Omodeo (hence the name of the lake), and for many years it was Europe's largest artificial basin. Before the area was flooded, the village Zuri was rebuilt higher up. Between 1982 and 1997 a new dam was built to extend the lake for irrigation purposes: its volume, from the original 403 million m3 reached the current 792.
Lake Omodeo is the largest of the many Italian artificial lakes, some of which are particularly famous. Just think, for example, of the lakes that flooded and covered entire villages, which now and then still testify for their previous existence. Just like Lake Vagli, in Tuscany. Every 10 years, in fact, water is partially removed for maintenance purposes: It is then possible to see the old village of Fabbriche di Careggine, submerged by the lake's waters in 1947. Lake Resia, is also very famous. This scenographic lake located at 1,498 m a.s.l. in the Italian "Alto-Adige" regional area: created in 1950 following the construction of dam that connected three natural lakes: Resia, Curon and San Valentino alla Muta. Curon Venosta, a small village, was submerged by the connecting waters. Today, the top part of the bell tower can still be seen as it springs out from the lake's waters. In winter, when the waters freeze to become ice, the tower can also be reached by foot.