Lakes are large bodies of standing water, either found naturally or man-made for amenity purposes
Dam of the Clywedog reservoir - The reservoir is used for supplying drinking water and preventing floods downstream. Water is not taken from the reservoir directly, but is released from the dam during dry periods to ensure that there is a sufficient supply for pumping stations downstream.


Lakes are large bodies of standing water, either formed naturally or man-made for amenity purposes. Water levels tend not to fluctuate to any great extent and gently shelving margins support a wide variety of flora and associated fauna.

Lakes also serve an important aesthetic role and, within the context of designed parkland, landscapes are important heritage assets. Lake Baikal is the world's oldest, largest, and deepest freshwater lake, nearly one mile deep and holding over 23,000 cubic kilometres of water.

Reservoirs: A reservoir is the same thing as a lake in many peoples' minds. But, in fact, a reservoir is a manmade lake that is created when a dam is built on a river. River water backs up behind the dam creating a reservoir. Reservoirs are built principally to provide water supply to homes, industry, agriculture as winter storage for crop irrigation or, in some cases, for electrical power generation. Upland reservoirs are commonly known as impoundment reservoirs since they are built across river valleys.


A common form of lowland reservoir is known as a pumped storage reservoir since water is pumped from a nearby river source rather than filling naturally as in the case of an impounding reservoir. Water supply reservoirs have developed into important nature conservation assets. The major difference between these water bodies and lakes or other areas of standing water, is the phenomenon of ‘draw-down’. This occurs when abstraction from the reservoir exceeds recharge from feeder streams and rivers, typically in summer, causing lowering of the water level.


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