Technology Spotlight/
Yu-Feng Forrest Lin, Technology Editor
Using Distributed Temperature Sensing for Hydrogeological Studies in China Jie Liu1 and Chunmiao Zheng2,3
Fiber-optic distributed temperature sensing (DTS) is a noninvasive thermal measurement method that can measure temperature spanning spatial scales from centimeters to kilometers collected at variable time scales with a resolution of up to 0.01◦ C and a spatial interval of down to 0.25 m (Selker et al. 2006; Tyler et al. 2009; Appendix S1 in the Supporting Information). Heihe River Basin (HRB) is in arid and semi-arid northwest China with very dynamic surface water-groundwater interactions in this region which are essential for water allocation and management (Yao et al. 2014). In two of recent studies in the summer of 2011 and 2012, respectively, fiber optical cables with the length of 500 to 2000 m were deployed in the Heihe River to obtain stream temperature records with a spatial resolution of 0.5 m and a temporal interval of 15 min. Compared to the traditional point temperature measurements, DTS data depict distributed temperature variations at a much higher spatiotemporal resolution and thus can reveal abnormal temperature patterns that may otherwise be neglected or hidden by point measurement methods (Figure S1 in Appendix S1). The application of DTS in the Heihe River was adversely affected when the river flow was high and the sediment load was heavy following rainfall events. Under those conditions, it was difficult to deploy the fiber-optic cables in the river channel and the cables were damaged at a high rate. Another application of DTS is in the desert of the lower HRB in July 2013. With limited precipitation of less than 50 mm/year, more than 130 desert lakes are scattered
1 Corresponding author: Center for Water Research, College of Engineering, Peking University, No. 60 Yannan Yuan, 100871 Beijing, China; +86-10-82529073; fax: +86-10-82529010; [email protected] 2 Center for Water Research, College of Engineering, Peking University, Beijing, China. 3 Department of Geological Sciences, University of Alabama, Tuscaloosa, AL. Received August 2014, accepted September 2014. © 2014, National Ground Water Association. doi: 10.1111/gwat.12298
NGWA.org
in this region, sustaining a unique desert-lake ecosystem. Groundwater is believed to be the major source of recharge for these desert lakes, but few studies have actually measured the groundwater discharge to the lakes and provided direct evidences of lake-groundwater interactions because of the rough field conditions and the difficulty to pinpoint the spots of groundwater discharge to the lakes. DTS was applied to continuously measure temperature variations in high resolution in one of the desert lakes, the Badain Lake. Different from the stream application, the use of DTS in lakes is less complicated and the effects of sedimentation and scouring are less significant, but the major challenge is the varying water depth to the lake bottom (Sebok et al. 2013). Thus it is important to eliminate other factors that affect lake temperature such as solar radiation and vertical temperature stratification, and ascertain that the temperature variations of the lake water are mainly determined by groundwater discharge to the lake. In one recent case study, the temperature distribution patterns of the entire lake with a temporal resolution of 5 min were obtained, which clearly indicated the locations of concentrated groundwater discharge to the Badain Lake. This directly measured temperature information confirms the previous hypothesis on the source of recharge for the desert lakes, and provides a good foundation for further quantitative analysis of lake-groundwater interactions in response to climate change and human activities. DTS has proven to be a very useful tool for hydrogeological studies, especially for understanding surface water-groundwater interactions under complex and extreme field conditions, as shown by the two recent applications in the HRB in China. It is noteworthy, however, that the application of DTS goes far beyond surface water-groundwater interactions. The authors’ team has started or is planning to extend the use of DTS to measure the temperature change in soils during ecohydrological experiments, monitor the temperature variation in snowpacks in the upper HRB that sustain stream runoffs to the middle and lower HRB, and detect Vol. 53, No. 1–Groundwater–January-February 2015
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the temperature breakthrough in well tests to estimate aquifer properties using the heat as a tracer.
Acknowledgments The authors are grateful to the assistance of John Selker and Scott Tyler who offered a short course on DTS at Peking University. Christopher Lowry provided valuable comments on an earlier draft. Li Huang, Chuankun Liu, Yingying Yao, and Xiang Huang contributed to the field work. The work was supported by the National Natural Science Foundation of China (Grants No. 91225301 and No. 91025019).
Supporting Information Additional Supporting Information may be found in the online version of this article:
References Sebok, E., C. Duque, J. Kazmierczak, P. Engesgaard, B. Nilsson, S. Karan, and M. Frandsen. 2013. High-resolution distributed temperature sensing to detect seasonal groundwater discharge into Lake Væng, Denmark. Water Resources Research 49, no. 6. DOI:10.1002/wrcr.20436. Selker, J., J. Th´evenaz, H. Huwald, A. Mallet, W. Luxemburg, N. Giesen, M. Stejskal, J. Zeman, M. Westhoff, and M. Parlange. 2006. Distributed fiber – optic temperature sensing for hydrologic systems. Water Resources Research 42, no. 12. DOI:10.1029/2006WR005326. Tyler, S.W., J.S. Selker, M.B. Hauser, C.E. Hatch, T. Torgersen, C.E. Thodal, and G. Schladow. 2009. Environmental temperature sensing using Raman spectra DTS fiberoptic methods. Water Resources Research 45: W00D23. DOI:10.1029/2008WR007052. Yao, Y.C., J. Zheng, G. Liu, H. Cao, H. Xiao, and W. Li. 2014. Conceptual and numerical models for groundwater flow in an arid inland river basin. Hydrological Processes. DOI:10.1002/hyp.10276.
Appendix S1. Demonstration of the Application of DTS in Streams
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Copyright of Ground Water is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
Yu-Feng Forrest Lin, Technology Editor
Using Distributed Temperature Sensing for Hydrogeological Studies in China Jie Liu1 and Chunmiao Zheng2,3
Fiber-optic distributed temperature sensing (DTS) is a noninvasive thermal measurement method that can measure temperature spanning spatial scales from centimeters to kilometers collected at variable time scales with a resolution of up to 0.01◦ C and a spatial interval of down to 0.25 m (Selker et al. 2006; Tyler et al. 2009; Appendix S1 in the Supporting Information). Heihe River Basin (HRB) is in arid and semi-arid northwest China with very dynamic surface water-groundwater interactions in this region which are essential for water allocation and management (Yao et al. 2014). In two of recent studies in the summer of 2011 and 2012, respectively, fiber optical cables with the length of 500 to 2000 m were deployed in the Heihe River to obtain stream temperature records with a spatial resolution of 0.5 m and a temporal interval of 15 min. Compared to the traditional point temperature measurements, DTS data depict distributed temperature variations at a much higher spatiotemporal resolution and thus can reveal abnormal temperature patterns that may otherwise be neglected or hidden by point measurement methods (Figure S1 in Appendix S1). The application of DTS in the Heihe River was adversely affected when the river flow was high and the sediment load was heavy following rainfall events. Under those conditions, it was difficult to deploy the fiber-optic cables in the river channel and the cables were damaged at a high rate. Another application of DTS is in the desert of the lower HRB in July 2013. With limited precipitation of less than 50 mm/year, more than 130 desert lakes are scattered
1 Corresponding author: Center for Water Research, College of Engineering, Peking University, No. 60 Yannan Yuan, 100871 Beijing, China; +86-10-82529073; fax: +86-10-82529010; [email protected] 2 Center for Water Research, College of Engineering, Peking University, Beijing, China. 3 Department of Geological Sciences, University of Alabama, Tuscaloosa, AL. Received August 2014, accepted September 2014. © 2014, National Ground Water Association. doi: 10.1111/gwat.12298
NGWA.org
in this region, sustaining a unique desert-lake ecosystem. Groundwater is believed to be the major source of recharge for these desert lakes, but few studies have actually measured the groundwater discharge to the lakes and provided direct evidences of lake-groundwater interactions because of the rough field conditions and the difficulty to pinpoint the spots of groundwater discharge to the lakes. DTS was applied to continuously measure temperature variations in high resolution in one of the desert lakes, the Badain Lake. Different from the stream application, the use of DTS in lakes is less complicated and the effects of sedimentation and scouring are less significant, but the major challenge is the varying water depth to the lake bottom (Sebok et al. 2013). Thus it is important to eliminate other factors that affect lake temperature such as solar radiation and vertical temperature stratification, and ascertain that the temperature variations of the lake water are mainly determined by groundwater discharge to the lake. In one recent case study, the temperature distribution patterns of the entire lake with a temporal resolution of 5 min were obtained, which clearly indicated the locations of concentrated groundwater discharge to the Badain Lake. This directly measured temperature information confirms the previous hypothesis on the source of recharge for the desert lakes, and provides a good foundation for further quantitative analysis of lake-groundwater interactions in response to climate change and human activities. DTS has proven to be a very useful tool for hydrogeological studies, especially for understanding surface water-groundwater interactions under complex and extreme field conditions, as shown by the two recent applications in the HRB in China. It is noteworthy, however, that the application of DTS goes far beyond surface water-groundwater interactions. The authors’ team has started or is planning to extend the use of DTS to measure the temperature change in soils during ecohydrological experiments, monitor the temperature variation in snowpacks in the upper HRB that sustain stream runoffs to the middle and lower HRB, and detect Vol. 53, No. 1–Groundwater–January-February 2015
17
the temperature breakthrough in well tests to estimate aquifer properties using the heat as a tracer.
Acknowledgments The authors are grateful to the assistance of John Selker and Scott Tyler who offered a short course on DTS at Peking University. Christopher Lowry provided valuable comments on an earlier draft. Li Huang, Chuankun Liu, Yingying Yao, and Xiang Huang contributed to the field work. The work was supported by the National Natural Science Foundation of China (Grants No. 91225301 and No. 91025019).
Supporting Information Additional Supporting Information may be found in the online version of this article:
References Sebok, E., C. Duque, J. Kazmierczak, P. Engesgaard, B. Nilsson, S. Karan, and M. Frandsen. 2013. High-resolution distributed temperature sensing to detect seasonal groundwater discharge into Lake Væng, Denmark. Water Resources Research 49, no. 6. DOI:10.1002/wrcr.20436. Selker, J., J. Th´evenaz, H. Huwald, A. Mallet, W. Luxemburg, N. Giesen, M. Stejskal, J. Zeman, M. Westhoff, and M. Parlange. 2006. Distributed fiber – optic temperature sensing for hydrologic systems. Water Resources Research 42, no. 12. DOI:10.1029/2006WR005326. Tyler, S.W., J.S. Selker, M.B. Hauser, C.E. Hatch, T. Torgersen, C.E. Thodal, and G. Schladow. 2009. Environmental temperature sensing using Raman spectra DTS fiberoptic methods. Water Resources Research 45: W00D23. DOI:10.1029/2008WR007052. Yao, Y.C., J. Zheng, G. Liu, H. Cao, H. Xiao, and W. Li. 2014. Conceptual and numerical models for groundwater flow in an arid inland river basin. Hydrological Processes. DOI:10.1002/hyp.10276.
Appendix S1. Demonstration of the Application of DTS in Streams
18
Vol. 53, No. 1–Groundwater–January-February 2015
NGWA.org
Copyright of Ground Water is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
