Tracer hydrology of the data-scarce and heterogeneous Central American Isthmus |
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Authors: | Ricardo Sánchez-Murillo Germain Esquivel-Hernández José L Corrales-Salazar Laura Castro-Chacón Ana M Durán-Quesada Manuel Guerrero-Hernández Valeria Delgado Javier Barberena Katia Montenegro-Rayo Heyddy Calderón Carlos Chevez Tania Peña-Paz Saúl García-Santos Pedro Ortiz-Roque Yaneth Alvarado-Callejas Laura Benegas Antonio Hernández-Antonio Marcela Matamoros-Ortega Lucia Ortega Stefan Terzer-Wassmuth |
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Institution: | 1. Stable Isotope Research Group, UNA-SIL, Universidad Nacional, Heredia, Costa Rica;2. Empresa de Servicios Públicos de Heredia, ESPH S.A., Heredia, Costa Rica;3. Atmospheric, Planetary and Oceanic Physics Department, School of Physics and Center of Geophysical Research, University of Costa Rica, San José, Costa Rica;4. Foundation for the Development of the Volcanic Central Cordillera, FUNDECOR, San José, Costa Rica;5. Centro para la Investigación en Recursos Acuáticos de Nicaragua, CIRA/UNAN-Managua, Universidad Nacional Autónoma de Nicaragua, Managua, Nicaragua;6. Institute of Geology and Geophysics, IGG-CIGEO, Universidad Nacional Autonoma de Nicaragua, Managua, Nicaragua;7. Water Resources Department,, Nicaraguan Institute of Territorial Studies, Managua, Nicaragua;8. Instituto Hondureño de Ciencias de la Tierra, IHCIT, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras;9. Servicio Autónomo Nacional de Acueductos y Alcantarillados, Gobierno de la República de Honduras, Tegucigalpa, Honduras;10. Centro Agronómico Tropical de Investigación y Enseñanza, CATIE, Turrialba, Costa Rica;11. Servicios de Investigación Científica y Técnica SC, Mexico, Mexico;12. Escuela de Biología, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras;13. International Atomic Energy Agency, Isotope Hydrology Section, Vienna International Center, Vienna, Austria |
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Abstract: | Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This work combines stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial–temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water–groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the mid-summer drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by (a) depleted recharge in highland areas (72.3%), (b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m a.s.l. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus. |
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Keywords: | Central American Isthmus Dry Corridor ENSO groundwater recharge processes water resources management water stable isotopes |
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