Free-Flowing Rivers
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Increase length of free-flowing rivers
Improving
Iberian Highlands
Spain
Problem: Important rivers in this landscape contain numerous anthropogenic barriers, such as weirs and dams, that block natural flows, reduce connectivity for fish species and impede natural hydrological processes.
Action: The project will map the barriers in the rivers in the watershed and prioritise those barriers that can be removed or mitigated to improve connectivity for fish populations. Weirs and dams will then be removed, where possible, or mitigated, for example by adding fish ladders.
Indicator: The length of river without barriers such as dams and weirs will indicate the increased river connectivity within the project landscape.
Methods
The barriers present on the rivers will be mapped by travelling along the riverbanks of the landscape during the season of lowest flow (late spring – summer). Each barrier found will be recorded, along with a physical description of the barrier and its coordinates.
As barriers are removed from the rivers, the location and date will be recorded. The length of free-flowing river without barriers in the project area will then be calculated and reported annually.
Dam removal on the Cabrillas river. Photo: AEMS – Ríos con Vida.
Results
At the start of the project in 2022 there was a maximum of 8km of the Cabrillas river that was free of barriers and no barriers had been removed by the project. During 2022, two weirs, Molino Bajo and the Molino del Cabrillas, were removed. This created a continuous, connected 25 km stretch of the Cabrillas river and reconnected it with the Tagus river. An interactive map of river connectivity can be found here.
Before (left) and after (right) removal of the Molino Bajo weir. Photo: AEMS – Ríos con Vida.
Partners
