Development of a laser-based water level sensor for fine-scale ecohydrological measurements

Benjamin, Joshua; Kaplan, D. A.

doi:10.1109/sustech.2017.8333522

Cited by 4 publications

(4 citation statements)

References 9 publications

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“…When connected to a time-keeping data logger, this technology is suitable for time-series collection (Benjamin and Kaplan, 2017). A recent development and test of a LiDAR-based system has demonstrated an outstanding precision of 0.5 mm (Table 1; Benjamin and Kaplan, 2017), but condensation and, in groundwater studies, borehole non-verticality, can interfere with the light reaching the water surface.…”

Section: Types Of Devicesmentioning

confidence: 99%

Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Rau¹,

Post²,

Shanafield³

et al. 2019

Preprint

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Abstract. Hydraulic head and gradient measurements underpin practically all investigations in hydro(geo)logy. There is sufficient information in the literature to suggest that head measurement errors may be so large that flow directions can not be inferred reliably, and that their magnitude can have as great an effect on the uncertainty of flow rates as the hydraulic conductivity. Yet, educational text books 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 measurements 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

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Section: Types Of Devicesmentioning

confidence: 99%

Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Rau¹,

Post²,

Shanafield³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…It is difficult to determine the accuracy of high-precision surveying because this must be compared to a more accurate benchmark method. The measurement error for state-of-theart survey devices depends on many factors, including instrument set-up, calibration, sun position, temperature elevation gradient, battery level and, most importantly, operator's expertise (Beshr and Abo Elnaga, 2011;Bitelli et al, 2018). The literature contains very few peer-reviewed investigations that test manufacturers' specifications.…”

Section: Relative Positioning Using Traditional Surveyingmentioning

confidence: 99%

“…There are also electronic water level measurement devices that emit a laser pulse and determine the depth of water from the time it takes the pulse to reach the water table and return to the sensor (known as lidar: light detection and ranging). When connected to a time-keeping data logger, this technology is suitable for time-series collection (Benjamin and Kaplan, 2017). A recent development and test of a lidar-based system demonstrated an outstanding precision of 0.5 mm (Table 1; Benjamin and Kaplan, 2017), but condensation and, in groundwater studies, borehole non-verticality can interfere with the light reaching the water surface.…”

Section: Types Of Devicesmentioning

confidence: 99%

“…When connected to a time-keeping data logger, this technology is suitable for time-series collection (Benjamin and Kaplan, 2017). A recent development and test of a lidar-based system demonstrated an outstanding precision of 0.5 mm (Table 1; Benjamin and Kaplan, 2017), but condensation and, in groundwater studies, borehole non-verticality can interfere with the light reaching the water surface.…”

Section: Types Of Devicesmentioning

confidence: 99%

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Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Rau

Post

Shanafield

et al. 2019

Hydrol. Earth Syst. Sci.

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Abstract. 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.

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Development of Agronomist Station System for Water Table Management at Peatland

Ismail

Shukri

Azmi

et al. 2019

2019 6th International Conference on Research and Innovation in Information Systems (ICRIIS)

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Development of a laser-based water level sensor for fine-scale ecohydrological measurements

Cited by 4 publications

References 9 publications

Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Error in hydraulic head and gradient time-series measurements: a quantitative appraisal

Development of Agronomist Station System for Water Table Management at Peatland

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