From Transboundary aquifers in Mexico by Gonzalo Hatch Kuri
60% of the planet’s freshwater is crossed by an international border; 40% of transboundary basins have a legal arrangement or international treaty; 145 countries share transboundary basins.
According to the United Nations (UN, 2008), a transboundary aquifer is a permeable water-bearing geological formation overlying a less permeable layer and the water contained in the saturated zone of the formation. It may be connected to a series of two or more hydraulically linked aquifers.
Transboundary aquifers. Source: UNESCO (2015).
Types of transboundary aquifers
There are two types of transboundary aquifers: confined and unconfined.
Confined transboundary aquifers are a geological formation in which the flow systems are between two layers of lower permeability and are therefore under much higher pressure.
Unconfined transboundary aquifers have a natural discharge connection to surface water bodies, such as a river or lake.
Other types of transboundary aquifers can be found in Eckstein and Eckstein (2005).
Types of transboundary aquifers: 1) jurisdictional boundary coincides with surface water catchment and groundwater divide; 2) surface and groundwater divides are separated from state boundary; recharge in one country, discharge in adjacent country; 3) state boundary coincides with major river or lake; alluvial aquifer connected to river; 4) large deep aquifer, recharge far from boundary, not connected to local surface and groundwater. Source: Rivera (2015).
Transboundary aquifers in the world:
Transboundary aquifers in the world.
Source: Stephan, Aureli, Dumont, Lipponen y Tiefenauer-Linardon (2022).
Model provisions on transboundary waters indicated by the UN:
- Equitable and reasonable use of groundwater.
- Sustainable use to avoid damaging its systemic functioning.
- Joint monitoring programs and standardization of information.
- States should cooperate in the integrated management of groundwater and surface water.
- Precautionary principle.
- Information exchange mechanisms.
- Water rights policy coordination schemes.
- Communication of plans for the future.
Fuentes
ONU, Organización de las Naciones Unidas. (11 de diciembre, 2008). Resolución 63/124 de la ONU “El Derecho a los Acuíferos Transfronterizos”. Nueva York, EUA: Organización de las Naciones Unidas.
Rivera, A. (2015). Journal of Hydrology: Regional Studies, 4(2015), 623-643.
Stephan, R. M., Aureli, A., Dumont, A., Lipponen, A., & Tiefenauer-Linardon, S. (2022). Informe Mundial de las Naciones Unidas sobre el Desarrollo de los Recursos Hídricos 2022: aguas subterráneas: hacer visible el recurso invisible (pp. 187-195). Montevideo, Uruguay: Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura, y Comisión Económica para Europa. Recuperado de https://unesdoc.unesco.org/search/N-EXPLORE-2dce9ac3-bbe4-4341-9e30-eb634ecdd02f
UNESCO, Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura. (2015). Estrategia regional para la evaluación y gestión de los sistemas acuíferos transfronterizos en las Américas. Montevideo, Uruguay: Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura.
UNESCO & PHI, Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura & Programa Hidrológico Intergubernamental. (2008). Identificación de acuíferos transfronterizos en México. Montevideo, Uruguay: Organización de las Naciones Unidas para la Educación, la Ciencia y la Cultura.
