16 October 2015
Dam construction often causes a range of stresses to the health of river ecosystems and the biodiversity they support. Despite their value to humans in terms of drinking water supply or hydropower generation, dams can change the course, speed and amount of water that flows in a river. As such, dams can exacerbate droughts and flashy floods (see, for example). Dams can also fragment migration routes for fish such as salmon and sea trout, and alter nutrient and sediment flows along the course of a river.