Its first meeting was organized by the UNESCO IHP National Committee of Transboundary Aquifer Systems Table 2. Transboundary Aquifer Systems of the World (numbers according to map, overleaf) Conclusions derived from the map of Transboundary Aquifer Systems Germany in Koblenz in June 2003, followed by a second session at UNESCO thus far No. Name of Transboundary Aquifer System Countries sharing this Type of Extension House in Paris in March 2004 and a third meeting, again in Paris, in April 2005. Just as there are many well-known transboundary river basins, so also there 2 aquifer system aquifer [km ] Although the information shown on this first global map of Transboundary The UNESCO regional offices and the National Committees of the UNESCO are less widely recognised transboundary aquifers. Such regional aquifers River Basins and Transboundary Aquifer Systems system * IHP, the continental vice presidents of the IAH and CGMW have provided a sometimes extend over large areas and their flow paths, crossing national Aquifer Systems have to be improved in many places, a number of conclusions North America can already be drawn: valuable contribution to the project. boundaries, can extend over tens or hundreds of kilometres. The extension of 101 Okanagan-Osoyoos / Grand Forks Canada, USA 1 Close cooperation with the International Groundwater Resources Assessment the largest systems known on our planet can even reach over two million 102 Poplar Canada, USA 1 1. Transboundary Aquifer Systems of sizeable extent exist on almost all Centre (IGRAC) is assured through UNESCO, and the WHYMAP data are square kilometres and can be shared by several countries. With thick saturated 103 Estevan Canada, USA 1 continents except for Australia that is not divided into different countries. In shared with IGRAC. Furthermore the Global Runoff Data Centre (GRDC) has sediments of 1000 m and more they form huge underground water reservoirs. 104 Châteauguay Canada, USA 2 2 500 many areas of large size countries, e.g. in North America (Canada, USA), 105 Basin and Range Aquifer System (Mexicalli, USA, Mexico 1 become part of the network providing valuable global and regional data sets Although there could be massive groundwater resources in stock, in arid Upper San Pedro) South America (Brazil, Argentina), Asia (China, Russia) the number of of surface water systems. Other regional centres, scientific organisations, regions, with little contemporary renewal from rainfall, aquifers can be particularly 106 Rio Grande Aquifer System (Hueco-Mesilla) USA, Mexico 1 10 800 Transboundary Aquifer Systems is by nature of definition relatively small, universities and freelance experts in hydrogeology may also participate in vulnerable to over-exploitation. Nevertheless they are mined, just like other 107 Gulf Coastal Plain Aquifer System USA, Mexico 1 10 000 compared to the rest of the world. WHYMAP in the future. deposits of natural raw materials (cf. Table 1). Many of the large transboundary Central and South America 2. Many Transboundary Aquifer Systems are located in the semi-arid to arid The structure of the WHYMAP network is shown in Figure 1. aquifers of Northern Africa and the Arab Peninsula were replenished during 201 Masacre / Arbonito / Pedernales Haiti, Dominican Republic regions of the world, where surface water is limited and the supply unreliable. the last ice age and contain good quality water, but they do not receive 202 Various Transboundary Aquifer Systems Mexico, Guatemala, Several Transboundary Aquifer Systems form large groundwater reservoirs, contemporary recharge. As the demand for water resources reaches higher Belize, Honduras, El Salvador however with non-renewable groundwater resources that can be exploited for levels, in arid regions these transboundary aquifers are often the only resource GROUNDWATER RESOURCES IHP Vice 203 Honduras - Nicaragua Aquifer System Honduras, Nicaragua only limited periods. Such aquifers require a particularly careful mapping, National Presidents for human needs, agricultural production and some aquatic ecosystems. 204 Nicaragua - Costa Rica Aquifer System Nicaragua, Costa Rica resource evaluation and reservoir modelling, to allow the sustainable use of Committees (8 regions) 205 Sixaola / Coto Costa Rica, Panama HYMAP the precious resources. OF THE WORLD W 206 Juradó Colombia, Panama Steering IAH 207 Táchira / Paranaguachón / Carrapia / Colombia, Venezuela IGCP Table 1. Selection of major aquifer systems containing predominantly non-renewable 3. Detailed information about the groundwater flow systems on either side of Commissions Monguí / Cretácico WHYMAP groundwater resources (FOSTER & LOUCKS 2006, modified) 208Llanura Río Arauca / San Antonio-Cucuta / Colombia, Venezuela the border are a basic requirement for sound groundwater management. TRANSBOUNDARY AQUIFER SYSTEMS executing Río Pamplonita / Guayabo / Carbonera / Therefore this information should be exchanged among the countries sharing UNESCO unit National Countries Aquifer System Extension (km2) Exploitable Mirador a Transboundary Aquifer System, and there must be a willingness to cooperate Regional 3 Committees Reserves (km ) 209 A-Sand / Cosewijne / Zanderij Guyana, Suriname, Offices in the joint management of the water resources. French Guiana Egypt, Libya, Sudan, Chad Nubian Sandstone 2 200 000 6 500 Committee 210 Costeiro Brazil, French Guiana 4. There are merely very few examples of well-studied Transboundary Aquifer C 1 : 50 000 000 IAEA o Algeria, Libya, Tunisia North Western Sahara 1 000 000 1 280 211 Tulcán Colombia, Ecuador m CGMW Systems and coherent hydrogeological modelling projects, e.g. in South America Isotope nsortiu 212 Ica / Machala / Zurumilla / Tumbes Brazil, Colombia, Peru, Regional Hydrology Algeria, Libya, Niger Murzuk Basin 450 000 60 - 80 Ecuador (the Guaraní Aquifer System) and North Africa (the Nubian Sandstone Aquifer Vice Presidents Section GRDC IGRAC 213 Solimoes Brazil, Peru, Bolivia System, the Northwest Sahara Aquifer System and the Iullemeden Aquifer Mauritania, Senegal, Gambia Maastrichtian 200 000 480 - 580 214 Titicaca Peru, Bolivia System). The wealth of Transboundary Aquifer Systems is yet to be studied International Regional 215 Ignimbritas Cordillera Ocidental / Bolivia, Peru, Chile Individual Mali, Niger, Nigeria Iullemeden Multilayer 500 000 250 - 2 000 in detail, which will require important investments in funding regional investigation, programmes, organisations, Concordia-Escritos / Caplina-La Yarada / freelance Universities Continental organisations, e.g. OSS, SADC, drilling and monitoring. This is a particular challenge both to international contributors Laguna Blanca-Maure institutions OAS ... Niger, Nigeria, Chad, Sudan, Chad Basin 600 000 170 - 350 216 Silala / Ascotal / Ollague Bolivia, Chile funding organisations and to national governments. Cameroon, Libya 217 Yrendá-Toba-Tarijeño Aquifer System Paraguay, Argentina, 1 350 000 Bolivia 5. The common study of Transboundary Aquifer Systems is regarded as an Figure 1. The WHYMAP network Botswana, Namibia, Central Kalahari 80 000 86 218Pantanal / Islas Brazil, Bolivia, Paraguay important tool to foster regional cooperation in many regions of the world, and South Africa Karroo Sandstone 219 Guaraní Aquifer System Brazil, Paraguay, 1, 2 1 200 000 the important shared water resources should be adequately capitalised in order Sources: The WHYMAP Consortium agreed on an iterative approach. This consists in Saudi Arabia, Bahrain, various including 225 000 - 250 000 500 - 2 185 Argentina, Uruguay Basins selected, derived and adjusted by 220 Chile - Argentina Aquifer System Chile, Argentina to recognise their value for sustainable development of the participating nations. Special Edition Qatar, United Arab Emirates Saq Aquifer Global Runoff Data Centre (GRDC), Koblenz 2005, the first instance of providing global data sets of hydrogeological and topographic major river major river basin land area without active river basins (desert, inland ice) major transboundary aquifer system based on HYDRO1K by USGS 221 El Condor Chile, Argentina Further conclusions can be drawn from the final map at the scale of 1:25.000.000, th information; then, collecting and capturing consolidated, up-to-date information; Jordan (only)* Qa Disi Aquifer 3 000 6 & WHYMAP 2006 for the 4 World Water Forum, which is expected to be issued prior to the UNESCO General Conference in and finally, establishing and maintaining a comprehensive Geo-Information Europe Mexico City Australia Great Artesian Basin 1 700 000 170 301 Carboniferous Limestone Aquifer France, Belgium 3 2007. System (WHYMAP-GIS) for groundwater relevant data on a global scale as 302 Northwest Germany - Netherlands Aquifer Germany, Netherlands 1 a global network on groundwater. * extends into Saudi Arabia, where it is known as the Saq Aquifer which is included in entry above 303 Northeast Germany - Pommeranian Aquifer Germany, Poland 1 March 2006 Groundwater, surface water and water in the atmosphere usually form a coherent entity known 304 East Prussian Aquifer Russia, Poland, Lithuania 1 WHYMAP and the World Map of Transboundary Aquifer Systems The WHYMAP Geo-Information System For a long time, hydrogeologists and other natural scientists have recognised FO Need for improvement as the hydrological cycle. This strong interlinking of water resources gives rise to the common 305 Latvia - Lithuanian - Estonian Aquifer Latvia, Lithuania, Estonia 2, 3 at the scale of 1 : 50 000 000 that man-made boundaries infrequently coincide