The Drina is a 346 km long international river, which forms a large portion of the border between Bosnia and Herzegovina and Serbia. It is the longest karst river in the Dinaric Alps. The Drina River has been transformed as the result of extensive sand and gravel extraction. Fish stocks have decreased, the surrounding forest belt has been destroyed and access to the bank has become restricted due the construction of illegal cottages along the shore, which has been fenced and illegally privatised. Excessively (illegal) excavation of sand and gravel is endangering drinking water sources, demolishing the natural ecosystems and destroying dikes that protect against floods.