Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in a Dune Sand Aquifer in Western Saudi Arabia: Assessment of Evaporation Loss for Design of an MAR System
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Water Desalination and Reuse Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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Earth Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
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U. A. Whitaker College of Engineering, Florida Gulf Coast University, 10501 FGCU Boulevard, Fort Myers, FL 33965-6565, USA
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Author to whom correspondence should be addressed.
Academic Editor: Y. Jun Xu
Water 2015, 7(12), 6967-6982; https://doi.org/10.3390/w7126669
Received: 5 September 2015 / Revised: 22 November 2015 / Accepted: 4 December 2015 / Published: 10 December 2015
(This article belongs to the Special Issue Water Resources Assessment and Management in Drylands)
Abstract
A component of designing a managed aquifer recharge system in a dune aquifer is the control of diffusive evaporative loss of water which is governed by the physical properties of the sediments and the position of the water table. A critical water table position is the “extinction depth”, below which no further loss of water occurs via diffusion. Field experiments were conducted to measure the extinction depth of sediments taken from a typical dune field in the region. The soil grain size characteristics, laboratory porosity, and saturated hydraulic conductivity were measured. The sand is classified as well-sorted, very fine sand with a mean grain diameter of 0.15 mm. Soil moisture gradients and diffusion loss rates were measured using sensors in a non-weighing lysimeter that was placed below land surface. The sand was saturated carefully with water from the bottom to the top and was exposed to the natural climate for a period of about two months. The moisture gradient showed a gradual decline during measurement until extinction depth was reached at about 100 cm below surface after 56 days. Diurnal temperature changes were observed in the upper 75 cm of the column and were negligible at greater depth. View Full-Text
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MDPI and ACS Style
Mughal, I.; Jadoon, K.Z.; Mai, P.M.; Al-Mashharawi, S.; Missimer, T.M. Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in a Dune Sand Aquifer in Western Saudi Arabia: Assessment of Evaporation Loss for Design of an MAR System. Water 2015, 7, 6967-6982.