Status: this discussion paper is a preprint. It has been under review for the journal Hydrology and Earth System Sciences (HESS). The manuscript was not accepted for further review after discussion.
Direct or indirect recharge on groundwater in the
middle-latitude desert of Otindag, China?
Bing-Qi Zhu,Xiao-Zong Ren,and Patrick Rioual
Abstract. The Otindag Desert in the middle-latitude desert zone of northern Hemisphere (NH) is essential to livestock-economy and ecoenvironment of northern China. Many areas in this zone are unexpectedly rich with groundwater resources although they have been under arid or hyper-arid climate for a long time. Widespread fresh groundwater deep to 60 m was found at the eastern part of the Otindag Desert. The occurrence of this massive fresh groundwater raises doubts on the long-lasting hypothesis in academic circles that regional atmospheric precipitation or palaeowater, namely the direct recharge, is the source of water in the middle-latitude desert aquifers of northern China. Understanding of the recharge of this fresh groundwater is important in evaluating the feasibility of groundwater exploitation and utilization. In this study we conducted hydrogeochemical and isotopical analyses to assess possible origin and recharge of these groundwaters. The analytical results indicate that the fresh groundwater is neither originated from regional atmospheric precipitation derived from the Asian Summer Monsoon system, nor from palaeowater that formed during the last glacial period. These findings suggest that the groundwater in this desert is possible to originate from remote mountain areas via the faults of the Solonker Suture zone, including the Daxing’Anlin and Yinshan Mountains. In addition, it is concluded that the hygeodrological linkage between desert aquifers and mountain systems through the suture zone is crucial to the hydrological functioning of the Otindag aquifer. This suggests that the modern indirect recharge mechanism, instead of the direct recharge and the palaeo-water recharge, is the most significant for groundwaterrecharge in the Otindag Desert. This study provides a new perspective into the origin and evolution of groundwater resources in the middle-latitude desert zone of HA.
Received: 23 Jul 2018 – Discussion started: 01 Nov 2018
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Although rainfall is scarce in global deserts, the Otindag Desert is abundant of water resources (mainly groundwater). To understand the water origin in this desert, stable and radioactive isotopes and hydrochemistry of natural waters were investigated. The groundwaters in the desert were young but not of meteoric origin, i.e., out of control by the modern and palaeo- direct recharge. The tectonic control, but not the climate control, is essentially responsible for the water origin there.
Although rainfall is scarce in global deserts, the Otindag Desert is abundant of water resources...
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