Water Flow Monitoring Research Articles

Vortex-assisted figure-eight wing power system

Due to the rising demand for low-cost clean energy, the development of efficient wind and water energy-generating systems is one of the major goals of this century. A novel approach for extracting energy efficiently from wind and water currents utilizes a tail-weighted wing following a figure-eight trajectory. Our prototype consists of a vertical ribbon-type wing suspended at its endpoints by swivel bearings. Energy is extracted from the longitudinal pumping motion that occurs at the endpoints of this flexing wing. Since the forces in these wings are in tension like a suspension bridge, the design can potentially be scaled up to much larger sizes than current systems and sweep across enormous areas of moving fluid with a relatively small amount of material. High-speed photography is used to map out the trajectory of a prototype wing and to monitor water flow around the wing. These observations along with data from an interactive computer simulation program are used to study the vortices and hydrodynamic forces that propel the wing along the figure-eight trajectory. Our prototype is low-cost, simple to fabricate and extracts a high amount, 30%, of the total energy in the water that flows through it.

Si-Micromachined Thermal Flow Sensors: Devices, Simulations and Applications

A thermal mass flow sensor in bulk micromaching membrane technology is presented. This anemometric sensor is suitable for measurements of gaseous and liquid media. Semiconductor fabrication technology and thus low costs per single device enable an application in large numbers due to upcoming demands for all kind of environmental control including water flow monitoring.

Flow measurements in sewers based on image analysis: automatic flow velocity algorithm

Discharges of combined sewer overflows (CSOs) and stormwater are recognized as an important source of environmental contamination. However, the harsh sewer environment and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. An in situ system for sewer water flow monitoring based on video images was evaluated. Algorithms to determine water velocities were developed based on image-processing techniques. The image-based water velocity algorithm identifies surface features and measures their positions with respect to real world coordinates. A web-based user interface and a three-tier system architecture enable remote configuration of the cameras and the image-processing algorithms in order to calculate automatically flow velocity on-line. Results of investigations conducted in a CSO are presented. The system was found to measure reliably water velocities, thereby providing the means to understand particular hydraulic behaviors.

Integrated cave drip monitoring for epikarst recharge estimation in a dry Mediterranean area, Sif Cave, Israel

AbstractUnderstanding recharge mechanisms and controls in karst regions is extremely important for managing water resources because of the dynamic nature of the system. The objective of this study was to evaluate water percolation through epikarst by monitoring water flow into a cave and conducting artificial irrigation and tracer experiments, at Sif Cave in Wadi Sussi, Israel from 2005 through 2007.The research is based on continuous high‐resolution direct measurements of both rainfall and water percolation in the cave chamber collected by three large PVC sheets which integrate drips from three different areas (17, 46, and 52 m2). Barrels equipped with pressure transducers record drip rate and volume for each of the three areas. The combined measured rainfall and cave data enables estimation of recharge into the epikarst and to better understand the relationship of rainfall‐recharge. Three distinct types of flow regimes were identified: (1) ‘Quick flow’ through preferential flow paths (large fractures and conduits); (2) ‘Intermediate flow’ through a secondary crack system; and (3) ‘Slow flow’ through the matrix. A threshold of ∼100 mm of rain at the beginning of the rainy season is required to increase soil water content allowing later rainfall events to percolate deeper through the soil and to initiate dripping in the cave. During winter, as the soil water content rises, the lag time between a rain event and cave drip response decreases. Annual recharge (140–160 mm in different areas in the cave) measured represents 30–35% of annual rainfall (460 mm). Copyright © 2011 John Wiley & Sons, Ltd.

Field monitoring and dual permeability modelling of water flow through unsaturated calcareous rocks

Summary Environmental monitoring was carried out in order to investigate the role of topsoil, rock matrix and fractures in controlling the water flow in unsaturated zone of calcareous rocks and in determining the timing and the magnitude of groundwater recharge. A comprehensive dataset of climate data, soil moisture and rock pressure heads was used to evaluate a physically based 1D dual permeability model, in order to simulate the water flow in the vertical profile to the groundwater table. The parameters of water retention and unsaturated hydraulic conductivity curves in soil and rock matrix were estimated using two evaporation experiments in the laboratory and the tension infiltrometer in the field. The other sensitive parameters of the model were calibrated using an optimization procedure based on combinations of randomly sampled parameters. Once the model had been calibrated, it was used to obtain insights into the hydrological processes through the unsaturated profile, down to the water table. The soil acts as a attenuation layer, determining the timing and the magnitude of drainage fluxes towards the unsaturated rock zone. The low permeability petrocalcic horizon below the soil, which frequently occurs in semi-arid regions, plays a key role in controlling the water exchanges between the soil and the rock. Most water flow in the top of the rock profile occurs through the fractures. This fracture flow becomes less along the profile, as a part of it gradually infiltrates into the unsaturated rock matrix. Fracture water infiltrates entirely into the matrix only when the unsaturated rock zone is very thick, so that in sites with a shallow water table fracture flow may be the dominant groundwater recharge mechanism. The flow through the matrix is continuous over time and at the water table it becomes constant and independent of large seasonal and annual variations in rainfall. The flow through the unsaturated matrix is the dominant groundwater recharge mechanism. In dry summers and in drought years the continuous matrix water flow sustains the recharge, thus maintaining high groundwater levels when more water is extracted. This is important in regions where groundwater from unconfined calcareous aquifers are important water resources. The recharge through the fractures is sensitive to the annual rainfall pattern and also contributes to the groundwater in years when the rainfall is greater.

In Situ Monitoring of Water Percolation and Solute Transport Using a Vadose Zone Monitoring System

Water percolation and tracer migration through the vadose zone underneath an ephemeral channel were studied using a vadose zone monitoring system (VMS) and application of a multitracer test. The VMS included flexible time‐domain reflectometry (FTDR) probes for continuous tracking of water content profiles, and vadose zone sampling ports (VSPs) for frequent sampling of the deep vadose pore water at multiple depths. The VMS was installed directly under an infiltration pond with several infiltration rings containing a traceable solution. Water content measurements by the FTDR probes allowed detailed visualization of the vadose wetting process; VSP samples allowed the establishment of tracer breakthrough curves at various depths. Flow velocities and fluxes were calculated from both the wetting process and the tracer breakthrough curves. The multitracer experiment revealed an unsteady flow pattern strongly affected by the layered structure of the sediments. The tracer breakthrough curves indicated domination of a mobile–immobile flow mechanism controlling contaminant migration across the vadose zone. The experimental setup demonstrated the ability of the VMS to provide real‐time monitoring of water flow and contaminant transport in the vadose zone.

Vision-based system for the control and measurement of wastewater flow rate in sewer systems

Combined sewer overflows and stormwater discharges represent an important source of contamination to the environment. However, the harsh environment inside sewers and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. In the following, we present and evaluate an in situ system for the monitoring of water flow in sewers based on video images. This paper focuses on the measurement of the water level based on image-processing techniques. The developed image-based water level algorithms identify the wall/water interface from sewer images and measure its position with respect to real world coordinates. A web-based user interface and a 3-tier system architecture enable the remote configuration of the cameras and the image-processing algorithms. Images acquired and processed by our system were found to reliably measure water levels and thereby to provide crucial information leading to better understand particular hydraulic behaviors. In terms of robustness and accuracy, the water level algorithm provided equal or better results compared to traditional water level probes in three different in situ configurations.

Monitoring water flow in a clay-shale hillslope from geophysical data fusion based on a fuzzy logic approach

Seismic and electrical resistivity tomography allow subsurface characterization from acoustic P-waves (Vp), shear S-waves (Vs) velocities, and electrical resistivity (ρ). Both geophysical methods were used to monitor water flow during a controlled rainfall experiment on a clay-shale hillslope located in the Laval catchment at Draix (Alpes-de-Haute-Provence, France). The objectives of the rainfall experiment were to analyse the water infiltration processes and identify possible water pathways by combining multi-method observations. The seismic data provide information on fissure density and the electrical resistivity data provide information on soil water content within the hillslope. Changes of the Vp and electrical resistivity fields with time show some similar pattern. To go further in the analysis of the water flow a geophysical data fusion strategy based on fuzzy set theory is applied. The computed fuzzy cross-sections based on expert hypotheses show the possibility for the material to be saturated during the rainfall experiment. The data fusion process is repeated in time for each acquisition set. The relative difference between the obtained fuzzy cross-sections is calculated and reveals possible locations where water may be transferred within the hillslope.

Controlling groundwater pumping online

Groundwater over-pumping is a major problem in several countries around the globe. Since controlling groundwater pumping through water flow meters is hardly feasible, the surrogate is to control electricity usage. This paper presents a framework to restrict groundwater pumping by implementing an annual individual electricity quota without interfering with the electricity pricing policy. The system could be monitored online through prepaid electricity meters. This provides low transaction costs of individual monitoring of users compared to the prohibitive costs of water flow metering and monitoring. The public groundwater managers' intervention is thus required to determine the water and electricity quota and watch the electricity use online. The proposed framework opens the door to the establishment of formal groundwater markets among users at very low transaction costs. A cost–benefit analysis over a 25-year period is used to evaluate the cost of non-action and compare it to the prepaid electricity quota framework in the Batinah coastal area of Oman. Results show that the damage cost to the community, if no active policy is implemented, amounts to (−$288) million. On the other hand, the implementation of a prepaid electricity quota with an online management system would result in a net present benefit of $199 million.

Increase in Phosphorus Losses from Grassland in Response to Olsen‐P Accumulation

The Olsen-P status of grazed grassland (Lolium perenne L.) swards in Northern Ireland was increased over a 5-yr period (March 2000 to February 2005) by applying different rates of P fertilizer (0, 10, 20, 40, or 80 kg P ha(-1) yr(-1)) to assess the relationship between soil P status and P losses in land drainage water and overland flow. Plots (0.2 ha) were hydrologically isolated and artificially drained to v-notch weirs, with flow proportional monitoring of drainage water and overland flow. Annually, the collectors for overland flow intercepted between 11 and 35% of the surplus rainfall. Single flow events accounted for up to 52% of the annual dissolved reactive phosphorus (DRP) load. The Olsen-P status of the soil influenced DRP and total phosphorus (TP) concentrations in land drainage water and overland flow. Annual TP loss was highly variable and ranged from 0.19 to 1.55 kg P ha(-1) yr(-1) for the plot receiving no P fertilizer and from 0.35 to 2.94 kg P ha(-1) yr(-1) for the plot receiving 80 kg P ha(-1) yr(-1). Despite the Olsen-P status in the soils ranging from 22 to 99 mg P kg(-1), after 5 yr of fertilizer P applications it was difficult to identify a clear Olsen-P concentration at which P losses increased. Any relationship was confounded by annual variability of hydrologic events and flows and by hydrologic differences between plots. Withholding P fertilizer for over 5 yr was not long enough to lower P losses or to have an adverse effect on herbage P concentrations.

The subsurface water system role for surface and coastal water pollution

This paper addresses two main questions: 1. What is the role and importance of the subsurface water system (soil water and groundwater) for determining nutrient and pollutant loading in surface and coastal waters, and the responses of this loading to different source abatement measures? 2. Is present water flow and quality monitoring sufficient for accurate understanding of this subsurface water system role? Simulation results for nitrogen loading in the Swedish Norrström drainage basin indicate that slow reversible mass transfer and transport processes in the subsurface may be essential for determining future surface and coastal water loads and their responses to various source abatement measures. Subsurface and surface water monitoring exemplification for Sweden and the whole Baltic Sea Drainage Basin, however, indicates important data gaps, which may make it difficult or impossible to discriminate among different possible interpretations and model quantifications of the subsurface water system processes and their contributions to nutrient and pollutant loading in surface and coastal waters.

High resolution NMR microscopy of plants and fungi.

Nuclear magnetic resonance (NMR) microscopy is a completely noninvasive technique that can be used to acquire images with high spatial resolution through opaque objects such as plant organs and tissue parts. The image contrast can be chosen to represent the anatomical details or to visualize the spatial distribution of a range of physico-chemical parameters such as the apparent diffusion constant of water or the velocity of water flow within plants in vivo. In addition, images can be generated which show the spatial distribution of metabolites. Furthermore, it is possible to detect chemical compounds labelled with the stable isotope (13)C and to generate images showing the spatial distribution of the (13)C label in the intact plant. The ability to monitor water flow and transport of (13)C-labelled tracer in intact plants with NMR microscopy favours the use of this technique in the investigation of long-distance transport processes in plants. A short introduction into the technical principles of NMR microscopy is provided and the problems associated with applications to plants are summarized. The potential of the technique is explained with applications to Zinnia elegans plants, wheat grains and Brassica napus siliques.

Long-term changes in quality of discharge water from abandoned underground coal mines in Uniontown Syncline, Fayette County, PA, USA

Changes in water quality over 25 years have been documented for discharges from an extensive network of abandoned underground coal mines in the Uniontown Syncline, Fayette County, PA, USA. A baseline study of 136 mine discharges in the syncline was conducted in 1974–1975. In 1998–2000, follow-up water flow and quality monitoring was conducted at 21 selected discharges for 2 years to assess the degree of mine water-quality improvement since 1974–1975. The data from the two periods of time were compared, with consideration of differences in measurement methods. The degree and rate of water-quality improvement was found to be highly dependent on the amount and duration of flooding in the mine voids. Water quality of discharges from the substantially flooded mine voids improved significantly, going from acidic water with high sulfate and iron concentrations in 1974–1975 to alkaline water with substantially lower sulfate and iron concentrations in 1998–2000. In contrast, the water quality in the unflooded mines showed less improvement over the 25 years between studies. The water discharging from the unflooded mines in 1974–1975 was acidic with high sulfate concentrations and in 1998–2000 was still acidic but showed somewhat lower sulfate and iron concentrations, reflecting depletion of readily available pyrite. The data obtained provide insight into the potential and rate of natural amelioration of mine water quality in different abandoned underground coal mine systems.

IRRIGATION CONTROL OF CONTAINER CROPS BY MEANS OF TENSIOMETERS

IRRIGATION CONTROL OF CONTAINER CROPS BY MEANS OF TENSIOMETERS

SW—Soil and Water: Monitoring Water Flow, Turbidity and Suspended Sediment Load, from an Apennine Catchment Basin, Italy

The aim of this paper is to discuss the results of a study conducted on the monitoring of the suspended sediment load and water flow of the Sillaro torrent, during 1997–2000. The river basin is located in the Northern Apennines in the province of Bologna in Italy. Its height is from 68 to 993 m above sea level. A clayey–waterproof soil characterises the 137·6 km 2 basin surface. The mean annual precipitation is 942 mm (1962–1983). The mean annual temperature is 11·8°C, while the maximum, registered in July, is 22°C. A station for measuring the amount of sediment yield and water flow was established at the outlet from the mountain basin of the Sillaro Torrent. The monitoring station was equipped with an ultrasonic flow meter and an automatic water sampler. The flow meter measured the hydraulic level, computed the water flow and sent signal to the water sampler, so that there would be a sample of sediment yield every 100000 m 3 of water crossing the section. The suspended sediment concentration (SSC) and the turbidity were measured on the samples, and the water samples were analysed by a laboratory turbidimeter. The best relationship between turbidity and SSC was established and applied to the turbidity of the samples so as to obtain the concentration of the suspended sediment. It was concluded that firstly, the instrumentation used for hydrologic monitoring is reliable, secondly, a simple linear regression of SSC and turbidity is adequate for an accurate estimation of the load and thirdly the multiplicative model of the suspended sediment yield on water flow is a statistically significant relationship.

Technical article: Monitoring water flow in the saturated zone using georadar

First BreakVolume 19, Issue 12 p. 679-684 Technical article: Monitoring water flow in the saturated zone using georadar First published: 21 December 2001 https://doi.org/10.1046/j.1365-2397.2001.00228.xCitations: 21AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume19, Issue12December 2001Pages 679-684 RelatedInformation

Conceptual model of the geometry and physics of water flow in a fractured basalt vadose zone

A conceptual model of the geometry and physics of water flow in a fractured basalt vadose zone was developed based on the results of lithological studies and a series of ponded infiltration tests conducted at the Box Canyon site near the Idaho National Engineering and Environmental Laboratory. The infiltration tests included one 2‐week test in 1996, three 2‐day tests in 1997, and one 4‐day test in 1997. For the various tests, initial infiltration rates ranged from 4.1 cm/d (4.75 ×10−7 m/s) to 17.7 cm/d (2.05×10−7 m/s) and then decreased with time, presumably because of mechanical or microbiological clogging of fractures and esicular basalt in the near‐surface zone, as well as the effect of entrapped air. The subsurface moisture redistribution was monitored with tensiometers, neutron logging, time domain reflectrometry, and ground‐penetrating radar. A conservative tracer, potassium bromide, was added to the pond water at a concentration of 3 g/L to monitor water flow with electrical resistivity probes and water sampling. Analysis of the data shows evidence of preferential flow rather than the propagation of a uniform wetting front. We propose a conceptual model describing the saturation‐desaturation behavior of the basalt, in which rapid preferential flow occurs through the largest vertical fractures, followed by a gradual wetting of other fractures and the basalt matrix. Fractures that are saturated early in the tests may become desaturated thereafter, which we attribute to the redistribution of water between fractures and matrix. Lateral movement of water takes place within horizontal fracture and rubble zones, enabling development of perched water bodies.

Monitoring of Water Flow and Solute Transport Through the Unsaturated Zone Using a Large‐Diameter Borehole

AbstractA method for monitoring water flow and solute transport through the unsaturated zone is of crucial necessity for early detection of threats to ground water. A method developed by Ukrainian hydrogeologists in the 1970s involves a borehole of a large enough diameter for a person to enter, that provides the possibility of installing monitoring equipment, and enables collecting undisturbed sediment blocks and samples of pore water and gas. Practically, tensiometers and vacuum lysimeters are installed at various levels in the borehole walls. They provide high quality sampling and measurements, and enable determining parameters of unsaturated water flow and solute transport and their temporal and spatial variability.The method was tested at several locations. Selected results from two sites, showing the temporal and spatial distributions of capillary pressure and solute concentrations, are presented. The results exhibit the difference between lateral variation in water flow and solute transport characteristics. The accuracy and representativeness of the measurements were tested against the mutual interaction between the various instruments installed in the borehole walls. Monitoring using the large‐diameter boreholes provides the possibility of early detection of threats to ground water under areal contamination inputs, and of quantitative prediction of its future trends.

Field monitoring of nitrate leaching and water flow in a structured clay soil

Bypass flow and nitrate leaching from a field at the experimental farm The Kandelaar farm in Eastern Flevoland in the Netherlands was measured in drain outflow for a period of 4 years. Automated monitoring equipment registered precipitation, groundwater level and drain discharge continuously and was complemented with manually collected data on soil water potentials and soil mineral nitrogen. Bypass flow occurred although the air-filled porosity in the soil was more than adequate to accept the rain. In a soil without macropores this would, therefore, not have led to any bypass flow. During bypass flow events in summer, 30% of the precipitation was directly discharged via the drains. In winter periods this amount corresponded to 84% of the precipitation. Bypass flow induced nitrate leaching from the fine aggregated top soil towards the groundwater. In periods with an active growing crop, nitrate leaching was negligible. A catch crop grown directly after slurry application in late summer seemed to have a reducing effect on nitrate leaching during the entire winter season. In the subsoil, large amounts of inaccessible nitrogen are present in the soil, within large soil peds. Soil structure strongly influences bypass flow and can be used as a management tool for farmers to decrease nitrate leaching.

3–-D Migration Experiment in Sparsely Fractured Crystalline Rock

AbstractA large scale tracer experiment has been performed in sparsely fractured granitic rock at 360 m depth. Nine different conservative tracers were injected at distances ranging between 10 and 56 m from a drift excavated for this experiment. The upper part of the test site was covered completely with plastic sheets. All the water entering into the drift could be collected. Water flow monitoring shows that water flow takes place in small areas with large dry areas in between. Of the nine injected tracers six reached the test site during the experiment. The fitting of the breakthrough curves to different models could not satisfactorily explain the actual processes involved in the tracer migration. The results of the tracer experiments and the Tritium measurements gave strong support to the notion that a non–negligible portion of the flow takes place in more or less isolated channels.