Thursday, 7 February 2008

Drought measures go to stage two

The recent rains in Catalonia had virtually no effect on shrinking reservoirs, prompting the government to introduce second-stage measures to conserve water. With water in the Ter and Llobregat reservoirs now at 23.6% of capacity, the Environmental Ministry has banned water use for pools and gardens, both public and private. In the latter case, watering is allowed only to ensure the survival of woodlands, the Ministry said. Water use for washing vehicles has also been banned, except at public car washes. (Full story in printed edition).


Arnau 9 February 2008 at 00:21  

Southern Catalans don't give a dam ("Sense presa")

Former and current Franquists often picture dams as a success of the former regime. Most dams were built in upstream portions of upper Catalonia rivers and had the main purpose of power generation (at the time hydroelectric power generation in Spain used to amount to over 50% of the total electrical consumption.) But this system planned by dictatorship technocrats has been proved to be highly ineffective regarding flooding of coastal areas and usage of seasonal floodwaters . However, since the end of the Franquism, no major project has been endeavored to improve the management of these problems in southern Catalonia.

Presently twelve water systems in southern Catalonia run with no flow regulation. Among these are the Besòs and Fluvià rivers and its tributaries. Smaller watercourses as the creeks in the Maresme region have no flow control either and its seasonal floodwaters are also wasted to the sea.

Among the reasons to avoid undertaking any project to avoid water flooding and to collect rain water in coastal areas is the fact that these watercourses have a very low average flow and run along highly populated areas. These are, nonetheless chief reasons to think about new water management solutions. Flooding of coastal areas occur almost every second year along the courses of unregulated rivers like Besòs and Fluvià. On the other hand, droughts are becoming a serious problem in the Barcelona area.

For instance, Besòs river – a system that takes two thirds of its water from the Ter and Llobregat systems- has a typical average Mediterranean flow of only 2 cubic meters per second . But this value is actually ten times higher than the median daily flow of Santa Ynez river in California prior to the construction of Cachuma reservoir in 1952.

Santa Ynez river flows used to be highly variable before its regulation and could multiply by 2000 during seasonal storms (twice as the Besòs river).

Considering an area of 400 square kilometers along the Besòs river and its tributaries where the annual precipitation is around 900 mm, a water collecting system could collect up to 360 milion cubic meters (Sau-Susqueda-Camarasa system has a capacity of 459 milion cubic meters.) Even collecting a fraction of this amount would be highly beneficial.

California seacoast projects like Cachuma, Santa Maria and Ventura are highly explanatory on what should be a properly planned water management project in a Mediterranean climate. Instead of poorly planned canals or inflatable dikes along the course of the river (as those made recently in the Besòs river) management of the level of the aquifers and capturing seasonal floodwaters are key in avoiding floods and fighting drought.

A project of this magnitude should include several regulating reservoirs and multiple conduits and water tunnels in both sides of the litoral mountains. Properly designed flow regulation must ensure environmentally healthier water systems.


Extracted from my personal blog