AECOM was appointed by the Ebro Water Authority in Spain to investigate fish mortalities and other episodes of water quality degradation that were initially attributed to illegal and sporadic toxic spills.

Extensive limnological research revealed that continuous and legal spills coming from two different chemical plants located upstream of the dam were causing the fish mortalities and other environmental problems. When released in the stream, this highly mineralized water soon reached the Cabriana reservoir and started to accumulate in the bottom of the water column due to its higher density. This resulted in a significant reduction of oxygen concentrations, which had a profound effect on the river’s water quality.

In order to mitigate the environmental problem, AECOM performed detailed engineering, purchase management, construction management, health and safety coordination, and start-up of a deep water intake project at the Cabriana Dam on the Ebro River. Water intake and transport are performed using the river energy and surface topography, and the whole system works without the need of an external energy source. The project increased the ecological stream-flow downstream of the dam and produced a major environmental improvement.