Calibration of regional hydraulic and transport properties of an arid-region aquifer under modern and paleorecharge conditions using water levels and environmental tracers

Müller, Th.; Sanford, Ward

Calibration of regional hydraulic and transport properties of an arid-region aquifer under modern and paleorecharge conditions using water levels and environmental tracers | Calage des propriétés régionales hydrauliques et de transport d’un aquifère de région aride sous des conditions actuelles et anciennes de recharge utilisant des niveaux d’eau et des traceurs environnementaux Calibración de las propiedades hidráulicas y del transporte regional de un acuífero de una región árida en condiciones actuales y de paleorecarga utilizando niveles de agua y trazadores ambientales 利用水位和和环境示踪剂校准现代补给和古代补给条件下的干旱地区含水层的区域水力特性和传输特性 Calibração das propriedades hidráulicas e de transporte regionais de um aquífero de região árida sob condições modernas e de paleo recarga usando níveis de água e traçadores ambientais

2019

Müller, Th. | Sanford, Ward

A two-dimensional numerical groundwater flow model was established and calibrated for the hyperarid Najd region in southern Oman. The results indicate that recent recharge rates are required to sustain the observed groundwater heads in the Najd. The model was also used to estimate possible ranges of past recharge rates and the effective porosity of the main aquifer unit. Recharge rates during past humid periods were estimated to be no more than 1–3 times modern rates. The effective porosity was estimated to be between 0.06 and 0.093. Insight into the nature of the long-term transport within the aquifer was gained by using transient model runs over the last 350 ka and (1) varying the recharge intensity (from 0.1 to 2.5 times modern), and (2) the timing and duration of humid and dry periods. Finally, results indicate that although recharge rates and the flow conditions have likely changed over time, a steady-state model is capable of reproducing the observed groundwater residence times in the Najd based on carbon-14, helium and chlorine-36 dating.

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