A dam, big or small, always means an abrupt dead end sign for a river. It alters everything, from the natural flow of water and fish to a long list of damages that are less visible but equally harmful. Most of the existing obstacles have no use today, they are nothing more than abandoned cement.

Small obsolete barriers block fish and sediment passage and altering the natural flow of water during seasons. It also creates a series of artificial ponds with accumulated sediment and other organic material. This stagnant water has poor oxygen levels with decomposing matter, paving the way for a rise in insects and spread of disease. They also act as obstacles for many watersports.

Bigger old dams come also with their own set of damages. Apart from the ones above, the water quality of the reservoir becomes poor closer to the dam, while larger quantities of gravel and sand accumulate dangerously on the dam instead of making their way to be deposited in river deltas and beaches along the coasts. The landscape downstream is disastrous, dried up and eroded soil, urban development in hazardous areas which were in earlier times covered with water, provoke many disasters and loss of lives in times of heavy rains.  Dams also disrupt tourism and local leisure spaces for citizens.  Some dams, still functioning well past their due date, require expensive maintenance and repair, and most times they cost much more than the revenue they produce. 

Read more about dam(ages) at #RiversUnlocked