Forests and water - case studies
Freshwater in the Mediterranean basin
The Mediterranean region is bioclimatically characterized by strong summer droughts. Over the past 20 years, most countries have experienced droughts lasting several years. Precipitation is irregular and often violent. Mediterranean high water often causes disastrous flooding, and rain is a major cause of soil erosion. Faced with these constraints, Mediterranean societies and governments have always endeavoured to manage water and soils efficiently, as demonstrated by the traditional expertise of farming communities and the major urban water works of antiquity. In the nineteenth and twentieth centuries, major drainage and irrigation works transformed numerous marshy plains into high-yielding land.
Nowadays, 300 billion m3 of water is used every day across the region. Water demand (consumption + losses from conveyance and distribution) doubled over the last century, and has increased by 60 percent over the past 25 years. It remains unevenly distributed from country to country, ranging from 100 to more than 1 000 m3/capita/year. The main cause of increased water use is irrigation, which represents 82 percent of the current demand in the South. As towns of more than 10 000 inhabitants will account for 80 million inhabitants by 2025 (compared with 43 million in 1995), water supply and sanitation needs for this population will also require more and more water, involving considerable investment in aqueducts and water treatment. In addition, rapidly developing tourism - the Mediterranean is the most visited destination in the world - greatly increases summer demand for potable water in coastal areas.
Water withdrawal already exceeds 50 percent of the renewable natural water in countries such as the Syrian Arab Republic, Tunisia and the Mediterranean watershed of Spain, and 90 percent in Egypt and Israel. Groundwater exploitation is more than 400 percent of renewable supply in the Libyan Arab Jamahiriya, which uses mainly non-renewable fossil resources. These averages mask extremely strong local pressures on water resources. The Mediterranean’s unsustainable water production index is the result of groundwater overexploitation by multiple, unsupportive and short-term users, and increased use of fossil resources.
Erosion, generated by the silting of reservoirs, is another cause of unsustainability, with annual losses of useful capacity of up to 2 to 3 percent in northern Africa. Half of Morocco’s existing useful capacity will be lost by 2050. Overexploitation of coastal aquifers has already caused a lot of nearly irreversible invasion by seawater. More than half - and up to 90 percent in some places - of the Mediterranean wetlands have disappeared, creating a huge impact on ecosystems. Conflicts of use and interest between upstream and downstream areas, cities and farming, and the short and the long term are about to get worse. Management costs for water protection, urban sanitation and pollution control are growing.
The question is how to avoid a breakdown in the balance of water supply and demand, while stabilizing pressure on the environment at an acceptable level and taking social and economic issues into account? The answer calls for closely combining resource management and water demand in order to stabilize the latter, particularly through reducing losses, increasing efficiency in use and arbitrating in resource allocation. This implies much determination and a new “water culture”, as well as renewed water policies. In particular, it means adopting performance and environmental and social conditionalities with defined quantified objectives, reallocating roles between the public and private sectors, changing behaviours through decentralizing and increasing stakeholder participation in management, and using technical and economic tools. Above all, it calls for structural adaptations of agricultural and rural development policies in the Mediterranean region, which should encourage consideration of environmental and social issues while seeking higher irrigation efficiency.
Adapted from L. Dassonville and L. Fé d’Ostiani. 2005. “Mediterranean watershed management: overcoming water crisis in the