TU Darmstadt / ULB / TUbiblio

Improving large-scale groundwater models by considering fossil gradients

Schulz, Stephan and Walther, Marc and Michelsen, Nils and Rausch, Randolf and Dirks, Heiko and Al-Saud, Mohammed and Merz, Ralf and Kolditz, Olaf and Schüth, Christoph (2017):
Improving large-scale groundwater models by considering fossil gradients.
In: Advances in Water Resources, Elsevier, pp. 32-43, 103, ISSN 03091708, DOI: 10.1016/j.advwatres.2017.02.010, [Online-Edition: https://www.sciencedirect.com/science/article/pii/S030917081...],
[Article]

Abstract

Due to limited availability of surface water, many arid to semi-arid countries rely on their groundwater resources. Despite the quasi-absence of present day replenishment, some of these groundwater bodies contain large amounts of water, which was recharged during pluvial periods of the Late Pleistocene to Early Holocene. These mostly fossil, non-renewable resources require different management schemes compared to those which are usually applied in renewable systems. Fossil groundwater is a finite resource and its withdrawal implies mining of aquifer storage reserves. Although they receive almost no recharge, some of them show notable hydraulic gradients and a flow towards their discharge areas, even without pumping. As a result, these systems have more discharge than recharge and hence are not in steady state, which makes their modelling, in particular the calibration, very challenging. In this study, we introduce a new calibration approach, composed of four steps: (i) estimating the fossil discharge component, (ii) determining the origin of fossil discharge, (iii) fitting the hydraulic conductivity with a pseudo steady-state model, and (iv) fitting the storage capacity with a transient model by reconstructing head drawdown induced by pumping activities. Finally, we test the relevance of our approach and evaluated the effect of considering or ignoring fossil gradients on aquifer parameterization for the Upper Mega Aquifer (UMA) on the Arabian Peninsula.

Item Type: Article
Erschienen: 2017
Creators: Schulz, Stephan and Walther, Marc and Michelsen, Nils and Rausch, Randolf and Dirks, Heiko and Al-Saud, Mohammed and Merz, Ralf and Kolditz, Olaf and Schüth, Christoph
Title: Improving large-scale groundwater models by considering fossil gradients
Language: English
Abstract:

Due to limited availability of surface water, many arid to semi-arid countries rely on their groundwater resources. Despite the quasi-absence of present day replenishment, some of these groundwater bodies contain large amounts of water, which was recharged during pluvial periods of the Late Pleistocene to Early Holocene. These mostly fossil, non-renewable resources require different management schemes compared to those which are usually applied in renewable systems. Fossil groundwater is a finite resource and its withdrawal implies mining of aquifer storage reserves. Although they receive almost no recharge, some of them show notable hydraulic gradients and a flow towards their discharge areas, even without pumping. As a result, these systems have more discharge than recharge and hence are not in steady state, which makes their modelling, in particular the calibration, very challenging. In this study, we introduce a new calibration approach, composed of four steps: (i) estimating the fossil discharge component, (ii) determining the origin of fossil discharge, (iii) fitting the hydraulic conductivity with a pseudo steady-state model, and (iv) fitting the storage capacity with a transient model by reconstructing head drawdown induced by pumping activities. Finally, we test the relevance of our approach and evaluated the effect of considering or ignoring fossil gradients on aquifer parameterization for the Upper Mega Aquifer (UMA) on the Arabian Peninsula.

Journal or Publication Title: Advances in Water Resources
Volume: 103
Publisher: Elsevier
Divisions: 11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Earth Science > Hydrogeology
11 Department of Materials and Earth Sciences
Date Deposited: 17 Apr 2018 12:48
DOI: 10.1016/j.advwatres.2017.02.010
Official URL: https://www.sciencedirect.com/science/article/pii/S030917081...
Export:

Optionen (nur für Redakteure)

View Item View Item