Groundwater recharge and palaeoclimate in the Sirte and Kufra basins, Libya

Isotopic tracing for conceptual models of groundwater hydrodynamics in multilayer aquifer systems of central and southern Tunisia

“…These vary from 0 to 7 pmC in the Djerid-Nefzaoua basin, from 7 to 36 pmC in the Sbeïtla (Dassi 2011) and from 3 to 44 pmC in the Gafsa-south basin (Hamed et al 2011). This relatively low 14 C activity, which confirms the palaeoclimatic origin of these waters, is comparable to that of Late Pleistocene and Early Holocene palaeogroundwaters identified at a local scale in southern and central Tunisia (Fontes et al 1983, Mamou 1990, Ouda 2000, Yermani 2002, Edmunds et al 2003, Zouari et al 2003, Jéribi 2004, Dassi et al 2005, Kamel et al 2005, Kamel et al 2006, Hamed et al 2008, and at a global scale in North Africa, the Middle East and the Arabian Peninsula (Conrad and Fontes 1970, Gonfiantini et al 1974, Pearson and Swarzenski 1974, Edmunds and Wright 1979, Fontes et al 1983, Fontes 1985, Stute and Schlosser 1993, Daoud 1995, Clark and Fritz 1997, Edmunds et al 1997, Abd El Samie and Sadek 2001, Edmunds et al 2003, Guendouz et al 2003, Edmunds 2005). In the Djerid-Nefzaoua basin, ages for waters with a 14 C activity below the detection limit of 2 pmC, corrected using various models, suggest a Late Pleistocene recharge period (up to 25 ka BP) for the component coming from Algeria.…”

Influence of precipitation and deep saline groundwater on the hydrological systems of Mediterranean coastal plains: a general overview

“…In fact, a change in the stable isotope composition of groundwater marking the transition from the Late Glacial to Holocene has been identified in many aquifers containing waters of different ages. Precipitation during the glacial periods is systematically depleted in heavy isotopes, as compared to modern precipitation, and has a deuterium excess lower than 10‰ (Gat and Carmi 1970, Edmunds and Wright 1979, Dray et al1998, Gaye 2001, Issar 2003. The depleted isotopic contents indicate lower temperatures during recharge processes.…”

“…The present recharge of the peri-Mediterranean aquifers is very small and only occurs at shallow levels and in areas where the aquifers become unconfined. Direct recharge through the aquifer outcrop or via the overlying soil has been calculated by some authors (Edmunds & Wright 1979, Mart & Ben Gai 1982, Lorusso et al 2003, and varies between 150 and 3 mm year -1 . Generally, variations in aquifer recharge not only change the aquifer yield or discharge, but also modify the groundwater flow systems.…”

Numerical groundwater modelling as an effective tool for management of water resources in arid areas

“…Groundwater is mainly used for irrigation, domestic, and small industrial purposes. Climate conditions have changed over the last 10 000 years from more humid conditions after the last Ice Age to arid conditions during the last 5000 years (Edmunds and Wright 1979, Edmunds 1994, Issar 2003. Under present climatic conditions, the rate of groundwater recharge is very low, so the groundwater resources will be exhausted in the near future if abstraction continues with present trends.…”