scholarly journals Investigating patterns and controls of groundwater up-welling in a lowland river by combining fibre-optic distributed temperature sensing with observations of vertical head gradients

2012 ◽  
Vol 9 (1) ◽  
pp. 337-378 ◽  
Author(s):  
S. Krause ◽  
T. Blume ◽  
N. J. Cassidy
Keyword(s):  
Surface Water ◽  
Water Exchange ◽  
Structural Heterogeneity ◽  
Small Scale ◽  
Lowland River ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Fibre Optic Cable ◽  
Cold Spots ◽  
Fast Flow

Abstract. This paper investigates the patterns and controls of aquifer-river exchange in a fast-flowing lowland river by the conjunctive use of streambed temperature anomalies identified with Fibre-optic Distributed Temperature Sensed (FO-DTS) and observations of vertical hydraulic gradients (VHG). FO-DTS temperature traces along this lowland river reach reveal discrete patterns with "cold spots" indicating groundwater up-welling. In contrast to previous studies using FO-DTS for investigation of groundwater-surface water exchange, the fibre-optic cable in this study was buried in the streambed sediments, ensuring clear signals despite fast flow and high discharges. During the observed summer baseflow period, streambed temperatures in groundwater up-welling locations were found to be up to 1.5 °C lower than ambient streambed temperatures. Due to the high river flows the cold spots were sharp and distinctly localized without measurable impact on downstream surface water temperature. VHG patterns along the stream reach were highly variable in space, revealing strong differences even at small scales. VHG patterns alone are indicators of both, structural heterogeneity of the stream bed as well as of the spatial heterogeneity of the groundwater-surface water exchange fluxes and are thus not conclusive in their interpretation. However, in combination with the high spatial resolution DTS data we were able to separate these two influences and clearly identify locations of enhanced exchange, while also obtaining information on the complex small-scale streambed transmissivity patterns responsible for the very discrete exchange patterns.

scholarly journals Investigating patterns and controls of groundwater up-welling in a lowland river by combining Fibre-optic Distributed Temperature Sensing with observations of vertical hydraulic gradients

2012 ◽  
Vol 16 (6) ◽  
pp. 1775-1792 ◽  
Author(s):  
S. Krause ◽  
T. Blume ◽  
N. J. Cassidy
Keyword(s):  
Surface Water ◽  
Water Exchange ◽  
Structural Heterogeneity ◽  
Temperature Sensing ◽  
Small Scale ◽  
Lowland River ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Hydraulic Gradients ◽  
Cold Spots

Abstract. This paper investigates the patterns and controls of aquifer–river exchange in a fast-flowing lowland river by the conjunctive use of streambed temperature anomalies identified with Fibre-optic Distributed Temperature Sensing (FO-DTS) and observations of vertical hydraulic gradients (VHG). FO-DTS temperature traces along this lowland river reach reveal discrete patterns with "cold spots" indicating groundwater up-welling. In contrast to previous studies using FO-DTS for investigation of groundwater–surface water exchange, the fibre-optic cable in this study was buried in the streambed sediments, ensuring clear signals despite fast flow and high discharges. During the observed summer baseflow period, streambed temperatures in groundwater up-welling locations were found to be up to 1.5 °C lower than ambient streambed temperatures. Due to the high river flows, the cold spots were sharp and distinctly localized without measurable impact on down-stream surface water temperature. VHG patterns along the stream reach were highly variable in space, revealing strong differences even at small scales. VHG patterns alone are indicators of both, structural heterogeneity of the stream bed as well as of the spatial heterogeneity of the groundwater–surface water exchange fluxes and are thus not conclusive in their interpretation. However, in combination with the high spatial resolution FO-DTS data we were able to separate these two influences and clearly identify locations of enhanced exchange, while also obtaining information on the complex small-scale streambed transmissivity patterns responsible for the very discrete exchange patterns. The validation of the combined VHG and FO-DTS approach provides an effective strategy for analysing drivers and controls of groundwater–surface water exchange, with implications for the quantification of biogeochemical cycling and contaminant transport at aquifer–river interfaces.

Fibre-optic distributed temperature sensing in combined sewer systems

2009 ◽  
Vol 60 (5) ◽  
pp. 1127-1134 ◽  
Author(s):  
R. P. S. Schilperoort ◽  
F. H. L. R. Clemens
Keyword(s):  
Temperature Sensing ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Sewer System ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Combined Sewer System ◽  
Fibre Optic Cable ◽  
Set Up ◽  
Single Instrument

This paper introduces the application of fibre-optic distributed temperature sensing (DTS) in combined sewer systems. The DTS-technique uses a fibre-optic cable that is inserted into a combined sewer system in combination with a laser instrument that performs measurements and logs the data. The DTS-technique allows monitoring in-sewer temperatures with dense spatial and temporal resolutions. The installation of a fibre-optic cable in a combined sewer system has proven feasible. The use of a single instrument in an easy accessible and safe location that can simultaneously monitor up to several hundreds of monitoring locations makes the DTS set-up easy in use and nearly free of maintenance. Temperature data from a one-week monitoring campaign in an 1,850 m combined sewer system shows the level of detail with which in-sewer processes that affect wastewater temperatures can be studied. Individual discharges from house-connections can be tracked in time and space. With a dedicated cable configuration the confluence of wastewater flows can be observed with a potential to derive the relative contributions of contributary flows to a total flow. Also, the inflow and in-sewer propagation of stormwater can be monitored.

Pipeline Leak Detection Using Four Mode Fibre-Optic Based Distributed Sensing

2014 ◽  
Author(s):  
Alastair Godfrey ◽  
David Hill ◽  
Chris Minto ◽  
John Williams ◽  
Jerry Worsley
Keyword(s):  
Negative Pressure ◽  
Acoustic Noise ◽  
Local Strain ◽  
Leak Detection ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Gradient Sensing ◽  
Highly Sensitive ◽  
Fibre Optic Cable ◽  
Ground Heave

Fibre-optic based Distributed Acoustic Sensing (DAS), is now commonly used around the world for providing pipeline operators with real-time and early warning of intrusions on their pipeline Right of Ways. Also open to analysis within the DAS signal return are multiple signatures derived from the egress of product leaking from pipelines. Over the last three years, focussing attention on these alternative signals, OptaSense have developed a novel 4-mode External Leak Detection capability, fusing outputs from both DAS, Negative Pressure Pulse (NPP) and Distributed Temperature Gradient Sensing (DTGS) signals (the latter not to be confused with Distributed Temperature Sensing or DTS). The first commercially deployed 4-mode Leak Detection products are now being seen on the market, for both gas and liquids pipelines. In this paper, we report how DAS can be used to provide these four modes of leak detection — including (listed in order of typical detection latency, fastest to slowest) i) negative pressure waves created in the pipeline product from the leak event ii) acoustic noise from turbulent flow through the leak orifice iii) temperature gradients in the soil due to the presence of the leaked product (positive and negative), and iv) local strain/ground heave due to soil displacement by the leaked product. These acoustic, temperature and strain measurements using a fibre-optic cable buried next to a pipeline can be fused together to provide highly sensitive and reliable alerts for pipeline leaks. The pipeline industry has always sought to detect smaller leaks faster, with better locational accuracy. This paper, which draws upon industry sponsored test results and commercial deployment data, provides an update to the industry on leak detection possibilities using DAS.

scholarly journals Practical considerations for enhanced-resolution coil-wrapped distributed temperature sensing

2016 ◽  
Vol 5 (1) ◽  
pp. 151-162 ◽  
Author(s):  
Koen Hilgersom ◽  
Tim van Emmerik ◽  
Anna Solcerova ◽  
Wouter Berghuijs ◽  
John Selker ◽  
...  
Keyword(s):  
Field Experiments ◽  
Construction Material ◽  
Study Data ◽  
Temperature Sensing ◽  
Temperature Measurements ◽  
Data Sets ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Enhanced Resolution ◽  
Fibre Optic Cable

Abstract. Fibre optic distributed temperature sensing (DTS) is widely applied in Earth sciences. Many applications require a spatial resolution higher than that provided by the DTS instrument. Measurements at these higher resolutions can be achieved with a fibre optic cable helically wrapped on a cylinder. The effect of the probe construction, such as its material, shape, and diameter, on the performance has been poorly understood. In this article, we study data sets obtained from a laboratory experiment using different cable and construction diameters, and three field experiments using different construction characteristics. This study shows that the construction material, shape, diameter, and cable attachment method can have a significant influence on DTS temperature measurements. We present a qualitative and quantitative approximation of errors introduced through the choice of auxiliary construction, influence of solar radiation, coil diameter, and cable attachment method. Our results provide insight into factors that influence DTS measurements, and we present a number of solutions to minimize these errors. These practical considerations allow designers of future DTS measurement set-ups to improve their environmental temperature measurements.

scholarly journals Revealing the influence of hyporheic water exchange on the composition and abundance of bottom-dwelling macroinvertebrates in a temperate lowland river

2021 ◽  
pp. 37
Author(s):  
Mateusz Grygoruk ◽  
Ewelina Szałkiewicz ◽  
Maria Grodzka-Łukaszewska ◽  
Dorota Mirosław-Świątek ◽  
Paweł Oglęcki ◽  
...  
Keyword(s):  
Surface Water ◽  
Pressure Gradient ◽  
Benthic Macroinvertebrates ◽  
Water Exchange ◽  
Hyporheic Zone ◽  
Field Measurements ◽  
Lowland River ◽  
Taxonomic Richness ◽  
Macroinvertebrate Fauna ◽  
Upwelling And Downwelling

We studied distributions and abundances of macroinvertebrates in relation to hyporheic water exchange (HWE) patterns of the upper Biebrza − a small, lowland, low dynamic European river located in Northeast Poland. On a 6-km stretch of the river; we determined the variability of water exchange in the hyporheic zone by using direct field measurements of the pressure gradient to determine groundwater–surface water interactions. We identified locations with upwelling and downwelling fluxes of HWE as well as ambiguous hydraulic contact between groundwater and surface water along the river. In these locations, we sampled bottom-dwelling macroinvertebrates. In total, 627 individuals of benthic macroinvertebrates of 34 taxa were identified. We revealed that bottom-dwelling macroinvertebrate fauna is more abundant and diverse in river stretches where water from the river infiltrates the hyporheic zone. Results also show higher taxonomic richness and abundances of benthic macroinvertebrates in stretches with diagnosed infiltrating conditions (downwelling flux in a hyporheic zone) compared to in stretches where the river drained groundwater (upwelling flux in a hyporheic zone), but the recorded differences were not statistically significant.

scholarly journals Practical considerations for enhanced-resolution coil-wrapped Distributed Temperature Sensing

2016 ◽  
Author(s):  
K. P. Hilgersom ◽  
T. H. M. van Emmerik ◽  
A. Solcerova ◽  
W. R. Berghuijs ◽  
J. S. Selker ◽  
...  
Keyword(s):  
Field Experiments ◽  
Construction Material ◽  
Temperature Sensing ◽  
Temperature Measurements ◽  
Fibre Optic ◽  
Distributed Temperature Sensing ◽  
Enhanced Resolution ◽  
Coil Diameter ◽  
Fibre Optic Cable ◽  
Insight Into

Abstract. Fibre optic Distributed Temperature Sensing (DTS) is widely applied in earth sciences. Many applications require a spatial resolution higher than the provided by the DTS instrument. Measurements at these higher resolutions can be achieved with a fibre optic cable helically wrapped on a cylinder. The effect of the probe construction, such as its material, shape, and diameter, on the performance has been poorly understood. In this article, we study datasets obtained from a laboratory experiment using different cable and construction diameters, and three field experiments using different construction characteristics. This study shows that the construction material, shape, diameter, and cable attachment method can have a significant influence on DTS temperature measurements. We present a qualitative and quantitative approximation of errors introduced through the choice of auxiliary construction, influence of solar radiation, coil diameter, and cable attachment method. Our results provide insight into factors that influence DTS measurements, and we present a number of solutions to minimize these errors. These practical considerations allow designers of future DTS measurement setups to improve their environmental temperature measurements.

Drivers of water exchange in the ORUST fjord system

2020 ◽  
Author(s):  
Sandra-Esther Brunnabend ◽  
Lars Axell ◽  
Maximo Garcia-Jove ◽  
Lars Arneborg
Keyword(s):  
Surface Water ◽  
Baltic Sea ◽  
Water Exchange ◽  
Sea Water ◽  
Water Masses ◽  
Open Boundary ◽  
Small Scale ◽  
Open Boundary Conditions ◽  
Near Surface ◽  
Fjord System

<p>The Orust fjord system, located on the west coast of Sweden, has openings on both ends and consists of several fjords that are connected by narrow and shallow channels. The fjord system includes the islands Orust and Tjörn as well as various smaller islands. The water exchange between the Kattegat and the different fjords is influenced by different factors, such as winds, tides, and density gradients. However, advection between the open sea and the complex fjord system are not yet well understood as lower resolution ocean models cannot resolve the small scale structures of the fjords and their connections. In addition, observations are rather sparse.</p><p>Therefore, the water exchange in the Orust fjord system is simulated using a high resolution (50 meter) NEMO3.6 ocean model setup, forced with the UERRA atmospheric reanalysis dataset. The lateral open boundary conditions for temperature, salinity, sea levels and velocities are provided by a low resolution (1.85 km) NEMO3.6 simulation, which spans the Baltic Sea and North Sea regions.</p><p>The model results are validated by comparison of modelled temperature, salinity, velocities and sea surface height with in-situ measurements. A detailed analysis of the different drivers of modelled water exchange between the Kattegat and the fjord system as well as between the different basins is presented. In general, the modelled water properties of the near surface layer in the fjord system are influenced by the Skagerrak surface water, which is controlled by the prevailing northward flowing Baltic Sea water. However, the residence times of water masses below the sill level are longer than the ones of the surface water masses as dense inflows of Skagerrak water in the basins create a strong stratification leading to weak vertical exchange.</p>

Managing the impacts of mining on Ghana’s water resources from a legal perspective

2018 ◽  
Vol 1 (3) ◽  
pp. 156-165 ◽  
Author(s):  
Nasirudeen Abdul Fatawu
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Small Scale ◽  
Mining Activities ◽  
Protection Agency ◽  
Environmental Laws ◽  
Mining Areas ◽  
Legal Perspective

Recent floods in Ghana are largely blamed on mining activities. Not only are lives lost through these floods, farms andproperties are destroyed as a result. Water resources are diverted, polluted and impounded upon by both large-scale minersand small-scale miners. Although these activities are largely blamed on behavioural attitudes that need to be changed, thereare legal dimensions that should be addressed as well. Coincidentally, a great proportion of the water resources of Ghana arewithin these mining areas thus the continual pollution of these surface water sources is a serious threat to the environmentand the development of the country as a whole. The environmental laws need to be oriented properly with adequate sanctionsto tackle the impacts mining has on water resources. The Environmental Impact Assessment (EIA) procedure needs to bestreamlined and undertaken by the Environmental Protection Agency (EPA) and not the company itself.

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