Water management in temporary rivers

In the Mediterranean most rivers hold water only intermittently. Hydrological, biogeochemical, sedimentary and ecological processes in these tributaries work very differently than in systems that carry water all of the time. The Mirage project should produce more knowledge about "drought management" in water management.

The quality of the water in our major rivers is mainly influenced by pollution, because humans have settled along rivers throughout history. "In the dry Mediterranean area, however, removal of water is the main problem," says Jochen Froebrich. "That leads not only to drying out, but also to pollution from point sources having a significant impact on the remaining water, for example, on the more elevated river bed surfaces and in the remaining pools." That is why in water management much more attention is needed for dealing with dryness. "River water that is dependent on wetlands, such as the Coto Donana at the mouth of the Guadalquivier in Andalusia or the La Mancha Lagoon, otherwise is at risk of drying out."

Froebrich initiated the Mediterranean Intermittent River Management project (Mirage) because while the European Water Framework Directive provides suitable guidelines for managing water-abundant rivers, too much is still unknown about streams that regularly fall dry. To be able to formulate management strategies for these too, the necessary knowledge was still lacking. This is made even more urgent by climate change, which causes hydrological extremes to occur more frequently. "We are now doing research in seven river basins," says Froebrich, "that together provide a good representation of the intermittently dry river basins in the Mediterranean area."

The local population is also emphatically involved, though this is not always easy. "Farmers are reluctant when it comes to measures that are good, for example, for biodiversity and clean water, but that come at the expense of their own economic and agricultural interests." Meanwhile, the project, which is being implemented with 16 other partners, is about half way. According to project leader Claire Jacobs, "We are now at a stage that we want more interaction with other Wageningen research groups with knowledge of hydrology and aquatic ecology."