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DOI	10.5194/hess-23-3603-2019
	Error in hydraulic head and gradient time-series measurements: A quantitative appraisal
	Rau G.C.; Post V.E.A.; Shanafield M.; Krekeler T.; Banks E.W.; Blum P.
发表日期	2019
ISSN	1027-5606
起始页码	3603
结束页码	3629
卷号	23 期号:9
英文摘要	Hydraulic head and gradient measurements underpin practically all investigations in hydrogeology. There is sufficient information in the literature to suggest that head measurement errors can impede the reliable detection of flow directions and significantly increase the uncertainty of groundwater flow rate calculations. Yet educational textbooks contain limited content regarding measurement techniques, and studies rarely report on measurement errors. The objective of our study is to review currently accepted standard operating procedures in hydrological research and to determine the smallest head gradients that can be resolved. To this aim, we first systematically investigate the systematic and random measurement errors involved in collecting time-series information on hydraulic head at a given location: (1) geospatial position, (2) point of head, (3) depth to water, and (4) water level time series. Then, by propagating the random errors, we find that with current standard practice, horizontal head gradients < 10-4 are resolvable at distances ≥170 m. Further, it takes extraordinary effort to measure hydraulic head gradients< 10-3 over distances < 10 m. In reality, accuracy will be worse than our theoretical estimates because of the many possible systematic errors. Regional flow on a scale of kilometres or more can be inferred with current best-practice methods, but processes such as vertical flow within an aquifer cannot be determined until more accurate and precise measurement methods are developed. Finally, we offer a concise set of recommendations for water level, hydraulic head and gradient time-series measurements. We anticipate that our work contributes to progressing the quality of head time-series data in the hydrogeological sciences and provides a starting point for the development of universal measurement protocols for water level data collection. © Author(s) 2019.
语种	英语
scopus关键词	Aquifers; Flow rate; Groundwater flow; Groundwater resources; Hydrogeology; Systematic errors; Time series; Uncertainty analysis; Water levels; Best practice methods; Flow rate calculations; Gradient measurement; Measurement protocol; Measurement techniques; Random measurement errors; Standard operating procedures; Time series informations; Random errors
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159615
作者单位	Rau, G.C., Karlsruhe Institute of Technology (KIT), Institute of Applied Geosciences (AGW), Karlsruhe, Germany, Connected Waters Initiative Research Centre (CWI), University of New South Wales (UNSW), Sydney, Australia; Post, V.E.A., Federal Institute for Geosciences and Natural Resources (BGR), Hanover, Germany; Shanafield, M., National Centre for Groundwater Research and Training (NCGRT), College of Science and Engineering, Flinders University, Adelaide, Australia; Krekeler, T., Federal Institute for Geosciences and Natural Resources (BGR), Hanover, Germany; Banks, E.W., National Centre for Groundwater Research and Training (NCGRT), College of Science and Engineering, Flinders University, Adelaide, Australia; Blum, P., Karlsruhe Institute of Technology (KIT), Institute of Applied Geosciences (AGW), Karlsruhe, Germany
推荐引用方式 GB/T 7714	Rau G.C.,Post V.E.A.,Shanafield M.,et al. Error in hydraulic head and gradient time-series measurements: A quantitative appraisal[J],2019,23(9).
APA	Rau G.C.,Post V.E.A.,Shanafield M.,Krekeler T.,Banks E.W.,&Blum P..(2019).Error in hydraulic head and gradient time-series measurements: A quantitative appraisal.Hydrology and Earth System Sciences,23(9).
MLA	Rau G.C.,et al."Error in hydraulic head and gradient time-series measurements: A quantitative appraisal".Hydrology and Earth System Sciences 23.9(2019).