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Blue treasure to protect

2008/03/01 Stephan, Raya - Ur-legedian aditua eta UNESCO-IHPren aholkularia Parisen | Otchet, Amy - UNESCOren programako zientzia-aditua Accrako bulegoan Iturria: Elhuyar aldizkaria

Under our feet there are aquifers that can extend thousands of kilometers. Like rivers, aquifers exceed country boundaries and can cover two or more countries. And unlike the rivers, we know little about the aquifers that extend above the limits. There are also no international rules and agreements on the joint management of these aquifers. To advance this path, in 2002, UNESCO developed the world aquifer map within the Internationally Shared Aquifer Resources Management-ISARM. In line with the International Association of Hydrologists (IAH), FAO, its local partners and international experts, the UNESCO International Hydrology Program (PEC) has been overseeing the global inventory of transboundary aquifers for the past five years.
Blue treasure to protect
01/03/2008 | Stephan, Raya 1 and Amani, Abou 2 and Otchet, Amy | 1 Expert in aquatic legislation and consultant to UNESCO-IHP in Paris: r.stephan@unesco.org; 2 Scientific expert of the UNESCO program at the Accra office: a.amani@unesco.org

(Photo: Archive)
The first study launched was in Africa. This study exposed 38 transboundary aquifers, of which 5 were unidentified. The degree of progress of this study was evaluated at a meeting held by UNESCO in Cotonou (Benin) in May 2007. This meeting recommended the development of an atlas of aquifers distributed in more than one nation by 2009.

The meeting was organized by the UNESCO Office for Accra and the International Association of Hydrologists (IAH) in collaboration with the Dutch International Groundwater Resource Assessment Centre. The information collected so far was analyzed and the last data collection was prepared for the regional inventory. Once completed, the inventory will be located in the database of the Geographic Information System (GIS) of transboundary aquifers of the region.

Hydrogeologists Benin, Burkina Faso, Côte d'Ivoire, Ghana, Mali, Mauritania, Niger, Nigeria, Togo and Senegal produced a status report based on data and information each provided on shared aquifers. The case of Ivory Coast is typical. It reflects the problems that countries in the region have in protecting this precious resource.

The case of Ivory Coast

In the Gulf of Guinea there are two shared aquifer systems with two large sedimentary basins: Basement Basin and Burning Basin. The Tano basin extends from the coastal town of Fresco in Ivory Coast to the town of Axim in Ghana, and the aquifer system covers 2.5% of the lands of Ivory Coast. In the Tano basin there are three types of aquifers. Quaternary aquifers (under 1.8 million years) have a high risk of contamination due to the proximity of the surface of the aquifer system to soil level. The second class is Miopliocene (5-8 million years) or terminal continental aquifers. One of them supplies drinking water to Abidja, the largest city in the Ivory Coast, and the surrounding regions. The third type of aquifer is that of the Upper Cretaceous (94 million years), which is the one that exploits the Société Africaine d'explotation d'eau Minérale. It is the most mysterious of the aquifers, since its geometry, volume, level and length are unknown.

Cotonou, the largest city in Benin. In 2002, Benin hydrogeologists found that the aquifer that supplies water to Cotonou also extends from the Togo border. Both countries have expressed interest in jointly managing this aquifer.
J. O'Sullivan/UNESCO

As in Abidja, most of the major cities of the Ivory Coast are located on the coast, including the Bono and the Aboisso. In addition, the region has numerous industries dedicated to the manufacture of pineapple, rubber and palm oil, as well as the gold mine Aboisson Afema. They all consume large amounts of water. And they cause contamination.

In groundwater studies in the Abidjan area, for example, it has been observed that the concentration of nitrates (NO 3 -), ammonium (NH 4 +) and aluminum (Al 3+) in the plateau, Adjamen and western area is too high, according to the drinking water standards of the World Health Organization (WHO). This chemical pollution is due to the use of pesticides and fertilizers on land -- fishermen are also contaminating ponds with pesticides -- even though other ponds have been contaminated by gold mining, including Ghana's Afema Lagoon, located next to it, and Aby Lagoon. In any case, regardless of source, contamination of surface waters with chemicals and household waste poses a threat to people's health and water biodiversity.

The Ivory Coast currently has 18 million inhabitants, half in urban areas, and if this figure is estimated to grow by 2% annually, it will reach about 24 million inhabitants by 2025. Also in Abidjan a strong population growth is taking place (in 1999 it was considered 3.2 million people) and the aquifer of the city is drowning, due to factors linked to the rapid urban process: the construction of buildings and infrastructures on land previously covered with vegetation makes the soil waterproof to rain. If we add that they occupy the soil anarchically with the houses of the neighborhoods, it is increasingly difficult to access the water wells to control the groundwater of the aquifer and facilitate the recharge of the aquifer. In addition, since there is no water treatment or waste disposal system, wastewater is poured directly into rivers and other surface waters, contaminating the aquifer also the city's external agriculture.

(Photo: UNESCO)
The strong demand for water in Abidjane makes the need for the city far superior to underground supply. It is expected that the bond will begin to use the groundwater that supplies the village environment, but it could also begin to use more than enough quickly. In addition, the amount of water taken from the Bonoua fountain has already doubled: In 1990, 767,767 m 3 and 1,836,699 m 3 were taken in 2000.

Another serious problem is salt water intrusion. This may be due to a high presence of chlorine in the coastal aquifer. In fact, excess chlorine has forced the population to abandon several wells. Specifically, hydrologists have detected this phenomenon beyond Jacqueville, the plain of Abidjan and the east of the Adiaké region.

In short, the main problem is that the state legal framework is not adequate. Laws dealing with the environment, water and mining sectors have been developed but have not yet come into force. A number of legal water resources have been confirmed in the Ivory Coast, but they focus mainly on marine and surface waters.

Early warning system

In 2002, the UNESCO Nairobi office and the United Nations Environment Programme launched a project to assess the impact of pollution on aquifers in eight other major cities in Abidjan and Africa. The cities analyzed were: Dakar (Senegal), Ouagadougou (Burkina Faso), Bamako (Mali), Cotonou (Benin), Keta (Ghana), Mombasa (Kenya), Addis Ababa (Ethiopia) and Lusaka (Zambia).

Contamination of surface waters with chemicals and household waste poses a threat to people's health and water biodiversity.
P. Virot/UNESCO

The project has developed various methodologies to assess groundwater vulnerability by identifying pollution hotspots and major threats. An early warning system has also been established. This system, made up of the network of African scientists, is raising awareness about the risks of waste dumping and similar activities, both in the public and private sectors, with decision-making capacity. "We were looking for a solid control system," says UNESCO program expert Emmanuel Naah, "in order to give prior warnings to legislators and water managers to act in time against pollution." The project is being further developed in line with the assessment recommendations of the workshop held in Cape Town (South Africa) in November 2005.

Compliance with legal vacuum

The description of transboundary aquifers is scientifically difficult, and political factors can further hinder the process. Governments often do not admit that in other countries the aquifers they use to obtain drinking water and to water. In addition, although there are increasing international standards and agreements on shared rivers, they do not apply fully in the case of aquifers.

Also, until recently, international legislation paid little attention to groundwater and transboundary aquifer systems. The only global agreement on water use, approved in May 1997, considers groundwater only when linked to surface water, as in most interstate treaties and transboundary water agreements.

Abidjan. Like him, most of the major cities of the Ivory Coast are located on the coast, including the Bono and the Aboisso.
ISS006E54425/NASA
However, things are changing. In 2006, the United Nations International Commission approved the first reading of the set of draft articles on transboundary aquifers, prepared on the scientific and technical basis of the International Hydrology Programme. As part of this effort, in the same year UNESCO and FAO jointly published a set of binding and non-binding international groundwater agreements.

The draft articles contain, on the one hand, the principles of international water law, wise use and the non-condition standard. It includes the general principle of international law, the obligation to cooperate and, in practice, the periodic exchange of data in the case of transboundary aquifers. On the other hand, specific principles of management of transboundary aquifers such as control, protection and conservation, and cooperation with developing countries directly or through the competent international body are codified.

In the only global agreement on the use of water resources to date, only groundwater is considered when linked to surface waters.
P. Virot/WHO

The Shared Aquifer Management Entity is promoting the development of Plans by governments, as well as the creation of Commissions for the joint management of shared resources with the environment and environmental protection. There are also plans for the implementation of legal agreements to improve aquifer protection.

Source: UNESCO. A blue goldmine in need of protection, A World of Science, 5. vol. No. 3, July-September 2007 (http://www.unesco.org/science/)

Article translated and adapted by Elhuyar with the authorization of UNESCO.

Why is it so difficult to clean contaminated aquifers?
Groundwater in world aquifers accounts for 30% of the world's freshwater supply, a percentage that is striking when compared to 0.3% of lakes and rivers. However, groundwater studies have generally been deficient, although the value of groundwater is evident and many countries meet their needs with them (for example, 80% of Mauritania's water needs are covered with aquifers). Also in more humid areas the population increasingly uses groundwater, since rivers and other surface waters are heavily contaminated.
(Photo: Archive)
Aquifers offer very safe and reliable resources, but they are fragile. It is very difficult, perhaps impossible, to clean the aquifers once contaminated. "Cleaning urban aquifers in some cases is technically impossible once contaminated and economically is not practical," says UNESCO programme expert Emmanuel Naah, who works at the UNESCO Regional Science Office in Nairobi, Kenya. "Therefore, in the long run, polluted groundwater in cities will be suppressed, severe water restrictions will occur, or complex and costly treatment systems will be built to prevent public health from being compromised."
Pollution of aquifers is due to wastewater and chemicals leaked by communities, factories and farms. In addition, sources of urban pollution are increasing: organic pesticides, nitrates, heavy metals, aquatic pathogens. The growth of cities significantly affects aquifers and the African urban population has multiplied by almost three since 1970. In fact, there are currently 35 new cities with more than a million inhabitants. This rural exodus has been aggravated by climatic conditions, desertification and poverty.
The case of North Africa
Government representatives have recognized the need to establish a legal agreement on the Nubian sandstone aquifer system that extends between Libya, Egypt, Chad and Sudan. Specifically, this system can be divided into two channels: the oldest and most widespread (Nubian aquifer system) and the post-Nubian aquifer system.
Ghadamès, known as the pearl of the desert, is located in an oasis. It is one of the oldest cities in the Sahara. The Libyan Great Man-Built River project transports about 500,000 m 3 of water to coastal cities that concentrate most of Libya's population through a 4-metre diameter concrete tube network. This artificial "river" extends under the desert and has a total length of 3,500 km.
(Photo: UNESCO)
The two torrents together retain about 373,000 km 3 of fossil water, which is billions of years old. That is the liquid legacy of the time when 10,000 years ago the Sahara was a savannah. The rains that fed the region disappeared about 3,000 years ago, leaving an exceptional but limited water supply, known as fossil waters. In 1991, the Government of Libya began working on this aquifer for the largest global civil engineering project: Rio Grande Built by Man. However, once this fossil water is definitively used, it will disappear definitively, which has generated a great debate around the project.
In 2000, Chad, Egypt, Libya and Sudan were included in the regional development programme of the Nordic sandstone aquifer strategy. The program was designed by the Center for Environmental Development for the Arab Region and Europe, based in Cairo. The second agreement, which included Algeria, Libya and Tunisia, established in 2002 a consultation mechanism for the North-Western Sahara aquifer system. The details of these and other agreements can be found in the Groundwater International Law, jointly published by UNESCO and FAO last year.
Stephan, Raya 1 and Amani, Abou 2 and Otchet, Amy
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