El Mar de Aral empieza a recuperarse

En el último número de la revista científica Nature sale publicado un artículo sobre los nuevos planes de recuperación del Mar de Aral.

Como sabeis, durante los años 60 este gran lago (el cuarto más extenso del mundo por aquel entonces) empezó a disminuir drásticamente su tamaño como consecuencia de los megalómanos planes soviéticos de irrigar las grandes llanuras del Kazakhstan para plantar algodón. La irrigación de estas llanuras se realizó mediante el uso de agua de los dos grandes ríos que alimentan este mar interior: el Syr-Darya y el Amu-Darya.

Como consecuencia de estos grandes planes de regadío, el Mar de Aral dejó de recibir la mayor parte de agua que lo alimentaba, disminuyendo su tamaño de forma espectacular. Las consecuencias medioambientales han sido enormes: rápidamente, el Mar de Aral se convirtió en un lago hipersalino (antes era casi dulce), lo que provocó la desaparición de toda la fauna piscícola de la que vivía mucha gente de los pueblos de alrededor, obligándolos a emigrar a otras regiones de la Unión Soviética. Los pesticidas, fertilizantes y otros elementos tóxicos empleados para potenciar el crecimiento del algodón han acabado concentrándose en el Mar de Aral (debido a la escorrentía superficial y subterránea) lo que ha provocado grandes problemas de salud, como índices de cáncer o de malformación en neonatos absolutamente intolerables en la población que aún habita en esas llanuras. La drástica disminución del Mar de Aral dejó expuestos al aire libre muchos sedimentos contaminados con pesticidas, exfoliantes y fertilizantes. Las numerosas tormentas de polvo que se producen en esta región ponen en suspensión estos sedimentos tóxicos que acaban siendo respirados por la población local, con los consiguientes problemas respiratorios. Por otra parte, la desaparición de esta gran masa de agua ha provocado que el clima de esta región haya sido fuertemente modificado.

Una de los últimos artículos donde se detalla este gran desastre medioambiental ha sido escrito por Philip Micklin (el mejor especialista de esta catástrofe y el primero en denunciarla) y lo podeis ver aquí.

Hay muchas fotografías disponibles en internet sobre esta gran catástrofe medioambiental pero las que más me han impresionado son las del fotógrafo Radek Skrivanek. También las podeis ver aquí, junto a una muy buena entrevista que le hizo un periodista de la Radio Free Europe Radio Liberty.

La disminución del nivel del agua del Mar de Aral provocó que en 1987 el lago quedase dividido en dos cuerpos de agua: el pequeño Mar de Aral, al norte, y el gran Mar de Aral, al sur.

Se han llevado a cabo diversas iniciativas para recuperar el Mar de Aral. En 1991, justo después del colapso de la Unión Soviética, se creó la Interstate Coordination Water Commission que consistía en una comisión formada por las Repúblicas Independientes de Asia Central (Kazakhstan, Kyrgyzstan, Tadjikistan, Turkmenistan y Uzbekistan) con el objetivo de intentar gestionar de forma racional los recursos hídricos de toda la cuenca hídrica del Mar de Aral. En 1993, esta Comisión acabó siendo integrada en la International Fund for saving the Aral Sea (IFAS). Esta Fundación internacional está participada, además de las 5 Repúblicas antes mencionadas, por muchos organismos internacionales como el Banco Mundial, las Naciones Unidas y la UE (a través del programa TACIS), entre otros. Aquí podeis ver la lista completa.

Una de las soluciones que mejores resultados estan dando fue adoptada en 2003. Se construyó un dique que permitió contener el agua procedente del río Syr-Darya en el Aral Norte. Este dique permitió disminuir la salinidad de esta parte del Aral y la reintroducción de peces. Ante estos resultados tan prometedores, se ha diseñado una segunda fase de recuperación, que es la que comenta el artículo en la revista Nature. Como siempre, os lo dejo a continuación:

Northern Aral Sea recovering
Kazakhstan plans second phase of project.
Daemon Fairless
The Aral Sea, whose disappearance counts as one of the world's worst environmental catastrophes, is making a modest recovery thanks to a series of water-management projects implemented by the World Bank and the government of Kazakhstan.

While the waters of the Aral Sea — now a chain of brackish lakes along the border of Kazakhstan and Uzbekistan — continue to shrink, one portion, the northern Aral in Kazakhstan, has been steadily rising thanks to improved flood levees and dam construction. Within the past year, the northern Aral has risen to the maximum holding capacity of its newly constructed dike — a process World Bank officials expected to take at least two or three years.

"The impact has been very swift and very important for the local people, both from a health point of view and from a livelihood point of view," says Joop Stoutjesdijk, team leader for the first phase of the World Bank's North Aral Sea project.

Building on this success, the Kazakh government is now conducting preliminary research for the next phase of their project.

Daene McKinney, an environmental engineer with the Center for Research in Water Resources at the University of Texas, Austin, and a former director of the United States Agency for International Development, says he is encouraged by the news. But he's not entirely optimistic. He points out that while the northern Aral is making a modest recovery, the southern Aral is still drying up.

"You have to be careful of being overly optimistic," he says. "If you ask: 'are they saving the Aral Sea?' the answer is clearly no."

High and dry

During the 1960s, the two rivers that fed the Aral — the Syr Darya, which empties into the northern Aral, and the Amu Darya, which empties into the southern Aral in Uzbekistan — were drastically diverted in order to increase agricultural efficiency under the Soviet regime.

The result is that the Aral, once the world's fourth largest inland body of water, has been steadily shrinking from the 67,000-square-kilometre sea that it was in the mid-1960s. At present it consists of a series of lakes, containing in total only about 10% of the sea's original volume1. Between 1987 and 1989 the water dropped severely, splitting the sea into two: the small northern Aral and the large southern Aral. Port towns were left stranded high and dry. "There were billions of cubic metres of water lost per year during the 1990s, says Stoutjesdijk.

Where there was once water and a thriving fishery, there is now desert wasteland, economic depression and disease; as the waters recede, they expose salt and sediment laced with agricultural residues — pesticides and chemical fertilizers — which have been linked to an increase in respiratory diseases and certain forms of cancer in the bordering communities.

Action plan

In 2001, the Kazakh government embarked on a US$85-million water-management project, securing $64.5 million in loans from the World Bank. The funds were used to improve the flow of the Syr Darya by constructing flood levees, improving hydraulic irrigation systems, and building dams to prevent over-spill from rivers and stop water draining from the northern Aral into the southern Aral.

Construction was completed in August 2005 and, by May 2006, the northern Aral had spread by nearly 900-3,300 square kilometres and risen by 3 metres — an impressive recovery. Previous attempts to contain the waters of the northern Aral with earthen dikes had failed and it wasn't clear whether or not the inflow originating from the Syd Darya river would be enough to significantly raise the water level.

With increased freshwater flow, the northern Aral's salinity is returning back to normal and, as a result, several species of freshwater fish have returned. And fishermen are once again casting their nets. "We're being told that for the first time since independence, they're exporting fish to the Ukraine again," says Stoutjesdijk.

North and south

McKinney says he is encouraged by the northern Aral's recovery. "It means that the water flow originating from the Syr Darya is enough to raise the northern Aral Sea up to levels that are adequate for the fish population and for the people who use them," he says.

But to save the entire sea, he notes, all of the water that is currently diverted from the Syr Darya and Amu Darya rivers for agricultural use would have to be directed back into the Aral. This is entirely unrealistic because agriculture, particularly of cotton, is a pillar of the Kazakh, Uzbek and other central Asian economies.

Still, the Kazakh government is eager to enhance the recovery of the northern Aral, and has begun preparations for a second stage of the project. Stoutjesdijk says he will be meeting with the Kazakh government sometime in 2008 to discuss further funding.