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NASA NTRS1993

Monitoring issues from a modeling perspective

Recognition that earth's climate and biogeophysical conditions are likely changing due to human activities has led to a heightened awareness of the need for improved long-term global monitoring. The present long-term measurement efforts tend to be spotty in space, inadequately calibrated in time, and internally inconsistent with respect to other instruments and measured quantities. In some cases, such as most of the biosphere, most chemicals, and much of the ocean, even a minimal monitoring program is not available. Recently, it has become painfully evident that emerging global change issues demand information and insights that the present global monitoring system simply cannot supply. This is because a monitoring system must provide much more than a statement of change at a given level of statistical confidence. It must describe changes in diverse parts of the entire earth system on regional to global scales. It must be able to provide enough input to allow an integrated physical characterization of the changes that have occurred. Finally, it must allow a separation of the observed changes into their natural and anthropogenic parts. The enormous policy significance of global change virtually guarantees an unprecedented level of scrutiny of the changes in the earth system and why they are happening. These pressures create a number of emerging challenges and opportunities. For example, they will require a growing partnership between the observational programs and the theory/modeling community. Without this partnership, the scientific community will likely fall short in the monitoring effort. The monitoring challenge before us is not to solve the problem now, but rather to set appropriate actions in motion so as to create the required framework for solution. Each individual piece needs to establish its role in the large problem and how the required interactions are to take place. Below, we emphasize some of the needs and opportunities that could and should be addressed through participation by the theoreticians and modelers in the global change monitoring effort.

Mahlman, Jerry D.↗
DOE OSTI2018

Ambient monitoring to inform the protection of beneficial uses and achieve water quality goals in Sinclair and Dyes Inlets, Puget Sound, WA

Currently discharge limits enforced under the Clean Water Act are focused on meeting water quality standards at the end of the pipe and environmental performance is measured based on meeting the discharge limits; but meeting discharge limits has very little to do with achieving water quality goals for coastal and estuarine ecosystems. Therefore, an effective monitoring and assessment program is needed to assess continuous process improvement, evaluate the ecological conditions, and provide metrics that can inform effective management of coastal and estuarine water quality. As part of an integrated Environmental Investment (ENVVEST) project for Sinclair and Dyes Inlets (ENVVEST 2006; Johnston et al. 2009) a network of monitoring stations was established to characterize environmental conditions, assess potential impacts, and establish environmental quality trends within the Inlets. Water, sediment, and biota monitoring locations were selected that were co-located near suspected sources (industrial, waste water, and stormwater outfalls; marinas, stream mouths, and other sources) or were representative of ambient marine and nearshore conditions. Water column stations and effluents from industrial outfalls were sampled seasonally for trace metals (Cd, Cr, Cu, Hg, Pb, and Zn) using analytical procedures appropriate for seawater (Strivens, Brandenberger and Johnston, 2018), conventional parameters (salinity, dissolved and total organic carbon, total and suspended solids, dissolved O2, pH, turbidity, NO2+NO3, NH4, N, and P), and toxicity. Effluent and water column toxicity tests included mysid shrimp (Americamysis bahia) 96 hr survival, sand dollar (Dendraster excentricus) or purple sea urchin (Strongylocentrotus purpuratus) 96 hr embryo development, QwikLite – dinoflagellate (Pyrocystis lunula) 24 hr bioluminescence response, mussel larvae (Mytilus sp.) 48 hr larvae survival and development, and kelp (Macrocystis pyrifera) 48 hr growth and germination. Additionally, indigenous mussels (Mytilis spp.) were sampled biennially for contaminant residues of metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), lipid content, and stable isotopes of C and N. The mussel data were compared to benchmarks of ecological effects (Johnston et al. 2007, Applied Biomonitoring 2009), samples obtained from a local seafood market harvested from Penn Cove on Whidbey Island (PKPLPC), and data from the national mussel watch status and trends monitoring program (Kimbrough et al. 2008). Results from 2009-2016 showed that dissolved metals nearly always met water quality standards and that water quality in Navy nearshore areas appeared to improve after best management practices (BMPs) for industrial process improvements (US Navy 2012) were completed in Sept. 2013 (Figure 1). In general, toxicity from exposure to whole effluent samples was not observed and ambient water samples were not toxic to test organisms, except that ambient toxicity was only observed during the presence of algal blooms which showed that toxicity was highly correlated with the abundance of the toxic algae Gymnodinium splendens (Rosen et al. 2009). Overall, mussel tissue residues were below benchmarks at most locations (Figure 2), however there were locations that had elevated levels of PAHs, PCBs, Hg, and Cu. Results from the monitoring provide metrics that are being used to assess progress toward meeting environmental quality goals for the watershed.

ENVVEST, PSEMP↗
DOE OSTI2026

Neutrino Beam Monitoring

Accelerator facilities produce neutrino beams from meson decays in a decay volume. Experiments measure event rates that depend on flux, cross sections, and detector response, so the flux is predicted using hadron production and beamline modeling and constrained by beam instrumentation, since near detectors alone cannot separate flux from cross section. Proton, hadron, and muon monitors can track the parent particle distributions and beam conditions, providing the inputs needed for flux predictions in long-baseline experiments such as NOvA, T2K, and DUNE. This talk reviews how beam monitors are used in practice to understand neutrino flux. Proton beam monitors tell where the beam hits the target and how stable it is. Farther downstream, hadron and muon monitors sample particles produced in meson decays. Because those muons come from the same parents as the neutrinos, their profiles reveal focusing, alignment shifts, and other changes in the beam, and they are routinely used to detect problems and guide flux predictions. The muon information can be used more quantitatively; for example, to infer the parent meson phase space, and fast radiation-hard timing detectors can add sensitivity to the momentum dependence of the focusing. These developments show both how tightly beam measurements can constrain the flux and where the current limits still lie. These approaches complement monitored-beam concepts, in which the decay region is instrumented to detect charged leptons from meson decays and to measure the neutrino flux directly.

Ganguly, Sudeshna [Fermilab] (ORCID:00000003163482↗
DOE OSTI2026

Neutrino Beam Monitoring

Accelerator facilities produce neutrino beams from meson decays in a decay volume. Experiments measure event rates that depend on flux, cross sections, and detector response, so the flux is predicted using hadron production and beamline modeling and constrained by beam instrumentation, since near detectors alone cannot separate flux from cross section. Proton, hadron, and muon monitors can track the parent particle distributions and beam conditions, providing the inputs needed for flux predictions in long-baseline experiments such as NOvA, T2K, and DUNE. This talk reviews how beam monitors are used in practice to understand neutrino flux. Proton beam monitors tell where the beam hits the target and how stable it is. Farther downstream, hadron and muon monitors sample particles produced in meson decays. Because those muons come from the same parents as the neutrinos, their profiles reveal focusing, alignment shifts, and other changes in the beam, and they are routinely used to detect problems and guide flux predictions. The muon information can be used more quantitatively; for example, to infer the parent meson phase space, and fast radiation-hard timing detectors can add sensitivity to the momentum dependence of the focusing. These developments show both how tightly beam measurements can constrain the flux and where the current limits still lie. These approaches complement monitored-beam concepts, in which the decay region is instrumented to detect charged leptons from meson decays and to measure the neutrino flux directly.

Ganguly, Sudeshna [Fermilab] (ORCID:00000003163482↗
NASA NTRS2021

The Analysis of Using Satellite Soil Moisture Observations for Flood Detection, Evaluating Over the Thailand’s Great Flood of 2011

A flood monitoring and warning system provides critical information that can protect property and save lives. A basin-scale flood monitoring system requires an effective observation platform that offers extensive ground coverage of flood conditions, low latency, and high spatiotemporal resolution. While satellite imagery offers substantial spatial flood extent in detail due to its high spatial resolution, the coarse temporal resolution and cloud obstruction limit its near real-time application. Daily soil moisture data derived from satellite sensors at a scale of a few km can be used to monitor extreme wet surface conditions arising in flood occurrences. This study analyses the flood detection capabilities of several sources of soil moisture information, including the Soil Moisture and Ocean Salinity mission (SMOS), the Advanced Microwave Scanning Radiometer on EOS (AMSR-E), the Advanced SCATterometer (ASCAT) on MetOp, the Global Land Data Assimilation System (GLDAS), and the WaterGAP Global Hydrology Model (WGHM). In addition to soil moisture, the analysis includes measurements of surface reflectance from the Moderate Resolution Imaging Spectroradiometer (MODIS), precipitation measurements from the Tropical Rainfall Measuring Mission (TRMM), and terrestrial water storage estimates from the Gravity Recovery And Climate Experiment (GRACE) as proxies for flood inundations. The analysis was conducted over the Chao Phraya River Basin (CPB) in Thailand, where the Great Flood of 2011 led to one of the most significant economic losses in the country's history. Satellite-derived soil moisture exhibits a stronger correlation with the flood inundations than the precipitation, model-derived soil moisture, and terrestrial water storage data. SMOS soil moisture observation agrees best with the MODIS-derived flood extent/occurrence, both in terms of spatial distribution and timing, and providing approximated flood lead-time of one week or longer. A neural network constructed from SMOS and MODIS data is used to predict flood intensity/occurrence (given soil moisture input) with a predicted time window from eight days to thirty-two days. The short-term prediction (e.g., eight days) achieves the highest accuracy with an averaged recovery rate of approximately 60% (correlation coefficient). This study's results suggest a potential application of satellite soil moisture data in assisting flood monitoring and warning systems.

Satellite soil moisture↗
DOE OSTI2013

Assessing human rights impacts in corporate development projects

Human rights impact assessment (HRIA) is a process for systematically identifying, predicting and responding to the potential impact on human rights of a business operation, capital project, government policy or trade agreement. Traditionally, it has been conducted as a desktop exercise to predict the effects of trade agreements and government policies on individuals and communities. In line with a growing call for multinational corporations to ensure they do not violate human rights in their activities, HRIA is increasingly incorporated into the standard suite of corporate development project impact assessments. In this context, the policy world's non-structured, desk-based approaches to HRIA are insufficient. Although a number of corporations have commissioned and conducted HRIA, no broadly accepted and validated assessment tool is currently available. The lack of standardisation has complicated efforts to evaluate the effectiveness of HRIA as a risk mitigation tool, and has caused confusion in the corporate world regarding company duties. Hence, clarification is needed. The objectives of this paper are (i) to describe an HRIA methodology, (ii) to provide a rationale for its components and design, and (iii) to illustrate implementation of HRIA using the methodology in two selected corporate development projects—a uranium mine in Malawi and a tree farm in Tanzania. We found that as a prognostic tool, HRIA could examine potential positive and negative human rights impacts and provide effective recommendations for mitigation. However, longer-term monitoring revealed that recommendations were unevenly implemented, dependent on market conditions and personnel movements. This instability in the approach to human rights suggests a need for on-going monitoring and surveillance. -- Highlights: • We developed a novel methodology for corporate human rights impact assessment. • We piloted the methodology on two corporate projects—a mine and a plantation. • Human rights impact assessment exposed impacts not foreseen in ESIA. • Corporations adopted the majority of findings, but not necessarily immediately. • Methodological advancements are expected for monitoring processes.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1996

Health Monitoring System for Composite Structures

An automated system was developed to monitor the health status of composites. It uses the vibration characteristics of composites to identify a component's damage condition. The vibration responses are characterized by a set of signal features defined in the time, frequency and spatial domains. The identification of these changes in the vibration characteristics corresponding to different health conditions was performed using pattern recognition principles. This allows efficient data reduction and interpretation of vast amounts of information. Test components were manufactured from isogrid panels to evaluate performance of the monitoring system. The components were damaged by impact to simulate different health conditions. Free vibration response was induced by a tap test on the test components. The monitoring system was trained using these free vibration responses to identify three different health conditions. They are undamaged vs. damaged, damage location and damage zone size. High reliability in identifying the correct component health condition was achieved by the monitoring system.

Tang, S. S.↗
DOE OSTI2019

Electrochemical Behavior of Steel in Concrete Under Wet and Dry Condition with NaCl Solution

The corrosion of steel and environmental factors in concrete under the wet and dry condition were examined by using electrochemical impedance spectroscopy (EIS) and microelectrode sensors. The concentration of chloride ion (CL) was detected by Ag/AgCl microelectrode, and the pH was monitored by W/WO{sub x} one. The CL increased step by step according to the wet and dry condition. Besides, the cathodic current of the oxygen (I{sub O{sub 2}}) was increased just after the immersion of concrete sample in wet process. These behaviors were thought to promote the corrosion of steel. From EIS, the rust was formed and destroyed on the surface of steel in concrete under the wet and dry condition. It was quantitatively demonstrated by monitoring that the corrosion of steel started when CL exceeded the threshold value in concrete under the wet and dry condition.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Reservoir Sediment Management and Monitoring Database

Overview This dataset compiles dam sediment management and monitoring information from surveys, case studies, and journal articles. Additionally, features described by the National Inventory of Dams (i.e., presence of sluice gates) are included to indicate known infrastructure features that may address sediment releases. The location and description of records from downstream monitoring gages are catalogued in order to help with tracking conditions over time (e.g., before and after management actions, as operations change, etc.). The data help address national scale understanding of challenges and solutions related to the accumulation of sediment behind a dam as well as downstream passage. Sediment trapping causes problems as it reduces storage capacity, disrupts dam and reservoir function, impedes access for recreation, alters water quality/habitat conditions, and contributes to riverbank and coastal erosion within the reservoir. Data compilation from a variety of sources is a first step towards assessing system-wide efficacy of management solutions. This dataset was developed under the Water Power Technologies Office funded effort which began as a Seedling on Reservoir Sedimentation Data, and was supported by the Reservoir Sedimentation Modeling Framework and Data Analysis project. These projects have addressed challenges in describing sediment transport, trapping, and management at dams throughout the US. Methodology An outer join on dams/reservoirs with surveys and survey reports (documented in the RESSED database, USBR or USACE databases, project websites, etc.) with the National Inventory of Dams, based on the NIDID to determine dams with documented management and/or sluice gates. Additional dams with documented management activity were identified through review of technical articles from the past 25 years in Journal of Hydrology, Journal of Water Resources Planning and Management, Geomorphology, Journal of Hydraulic Engineering, Water, Journal of Cleaner Production, International Journal of Sediment Research, Nature Scientific Reports, Earth Surface Processes and Landforms, and Environmental Science and Pollution Research. Individual records were created for each survey or management activity documented. To evaluate downstream sediment monitoring records, the nhdPlusTools and dataRetrieval packages in R were used to find gages within 10km of each dam in the management database. Length of record and location of matched gages were retrieved for those parameters relevant to sediment concentration or total sediment discharge.

Hansen, Carly [ORNL] (ORCID:0000000193280838)↗
DOE OSTI2017

Coincident aboveground and belowground autonomous monitoring to quantify covariability in permafrost, soil, and vegetation properties in Arctic tundra

Coincident monitoring of the spatiotemporal distribution of and interactions between land, soil, and permafrost properties is important for advancing our understanding of ecosystem dynamics. In this paper, a novel monitoring strategy was developed to quantify complex Arctic ecosystem responses to the seasonal freeze-thaw-growing season conditions. The strategy exploited autonomous measurements obtained through electrical resistivity tomography to monitor soil properties, pole-mounted optical cameras to monitor vegetation dynamics, point probes to measure soil temperature, and periodic manual measurements of thaw layer thickness, snow thickness, and soil dielectric permittivity. The spatially and temporally dense monitoring data sets revealed several insights about tundra system behavior at a site located near Barrow, AK. In the active layer, the soil electrical conductivity (a proxy for soil water content) indicated an increasing positive correlation with the green chromatic coordinate (a proxy for vegetation vigor) over the growing season, with the strongest correlation (R = 0.89) near the typical peak of the growing season. Soil conductivity and green chromatic coordinate also showed significant positive correlations with thaw depth, which is influenced by soil and surface properties. In the permafrost, soil electrical conductivity revealed annual variations in solute concentration and unfrozen water content, even at temperatures well below 0°C in saline permafrost. These conditions may contribute to an acceleration of long-term thaw in Coastal permafrost regions. Finally, demonstration of this first aboveground and belowground geophysical monitoring approach within an Arctic ecosystem illustrates its significant potential to remotely “visualize” permafrost, soil, and vegetation ecosystem codynamics in high resolution over field relevant scales.

58 GEOSCIENCES↗
DOE OSTI2016

New portable instrument for the measurement of thermal conductivity in gas process conditions

The development of high temperature gas sensors for the monitoring and determination of thermophysical properties of complex process mixtures at high temperatures faces several problems, related with the materials compatibility, active sensing parts sensitivity, and lifetime. Ceramic/thin metal films based sensors, previously developed for the determination of thermal conductivity of molten materials up to 1200 °C, were redesigned, constructed, and applied for thermal conductivity measuring sensors. Platinum resistance thermometers were also developed using the same technology, to be used in the temperature measurement, which were also constructed and tested. A new data acquisition system for the thermal conductivity sensors, based on a linearization of the transient hot-strip model, including a portable electronic bridge for the measurement of the thermal conductivity in gas process conditions was also developed. The equipment is capable of measuring the thermal conductivity of gaseous phases with an accuracy of 2%-5% up to 840 °C (95% confidence level). The development of sensors up to 1200 °C, present at the core of the combustion chambers, will be done in a near future.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

2016 Inspection and Annual Site Status Report for the Site A/Plot M, Illinois, Decommissioned Reactor Site July 2016

The Site A/Plot M, Illinois, Decommissioned Reactor Site was inspected on May 17, 2016. The site, located within Cook County forest preserve that is open to the public, was found to be in good condition with one exception. Erosion on top of the grass-covered mound at Plot M continues to be a concern as presented in previous inspections. Ruts form in the soil on top of Plot M as a result of bike traffic using the open field as a pass thru between established bike trails within the forest preserve. Argonne National Laboratory (ANL) who is contracted directly from U.S. Department of Energy (DOE) has filled in the ruts with top soil and reseeding remains an ongoing process. Reseeded areas from 2015 are progressing nicely. No cause for a follow-up inspection was identified. In 2015, ANL plugged and abandoned 8 of 25 monitoring wells (BH41, BH51, BH52, BH54, DH9, DH10, DH13, and DH17). The 17 groundwater monitoring wells remaining at the site were inspected to confirm that they were locked and in good condition. Preliminary environmental monitoring results for 2015 are provided in a draft report titled Surveillance of Site A and Plot M, Report for 2015, prepared by ANL. The report also contains results of an independent analysis conducted by the Illinois Emergency Management Agency on some of the samples collected by ANL in 2015. The draft report states that the results of the surveillance program continue to indicate that the impact of radioactivity at Site A/Plot M is very low and does not endanger the health of those living in the area or visiting the site. The ANL monitoring report will be made available to the public on the DOE Office of Legacy Management public website when it is issued as final. A new county forest preserve campsite opened in 2015 at Bull Frog Lake, which is east of Plot M. Hiking trails connect Bull Frog Lake with Site A/Plot M. The site might receive more traffic from forest preserve visitors now that this new campsite is opened.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2011

The CDMS II data acquisition system

The Data Acquisition System for the CDMS II dark matter experiment was designed and built when the experiment moved to its new underground installation at the Soudan Lab. The combination of remote operation and increased data load necessitated a completely new design. Elements of the original LabView system remained as stand-alone diagnostic programs, but the main data processing moved to a VME-based system with custom electronics for signal conditioning, trigger formation and buffering. The data rate was increased 100-fold and the automated cryogenic system was linked to the data acquisition. A modular server framework with associated user interfaces was implemented in Java to allow control and monitoring of the entire experiment remotely.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2025

Tracking Local pH Dynamics during Water Electrolysis via In-Line Continuous Flow Raman Spectroscopy

The performance of electrochemical devices, which play a critical role in decarbonization efforts, is often governed by proton-coupled electron transfer reactions at the electrode–electrolyte interface. These reactions are highly sensitive to the complex and dynamic microenvironment present at the electrode surface. However, characterizing this environment─particularly monitoring interfacial pH and its evolution under reaction conditions─remains challenging, necessitating the development of advanced analytical tools. Here, in this study, we introduce in-line continuous flow Raman spectroscopy (CFRS) as a spectroelectrochemical platform for quantifying interfacial pH swings generated during water-splitting. By monitoring phosphate ion speciation and controlling the hydrodynamics with a flow cell, we measure pH swings as a function of current density, flow rate, and distance from the electrode. Comparison with theoretical models reveals the impact of bulk pH, boundary layer thickness, and bubble dynamics at high current densities. Collectively, these findings establish CFRS as a platform for quantitatively investigating pH dynamics, offering critical insights for advancing electrochemical energy conversion technologies.

Marquez, Raul A. [Univ. of Texas, Austin, TX (Unit↗
DOE OSTI2024

Height-resolved emission spectroscopy and high-speed imaging of the TiAl6V4 vapor plume under laser powder bed fusion conditions

Optical emission spectroscopy is increasingly used as an in situ monitoring technique during laser powder bed fusion (LPBF) because plume emission holds elemental information not found in other in situ sensing techniques. This work explores the shape, stability, and temperature of the emission plume above the melt pool of Ti6Al4 V undergoing laser scans under LPBF-like processing conditions, using high-speed video and height-resolved spectroscopy to study the details of plume dynamics. Optical emission spectroscopy is conducted in the 480 nm to 525 nm region, where Ti emission is strong, with 0.3 mm vertical resolution above the baseplate. The Boltzmann plot method is used to determine temperature at each probed elevation, which indicates that the hottest location of the plume is occasionally elevated 0.3 mm to 0.6 mm above the scanning surface. The results show that the plume shape, stability, temperature, and spectra are highly dependent on the processing conditions. We highlight some of the complexities of optical emission spectroscopy and discuss potential challenges for implementing optical emission spectroscopy across an entire build.

36 MATERIALS SCIENCE↗
NASA NTRS2011

Using Enhanced Grace Water Storage Data to Improve Drought Detection by the U.S. and North American Drought Monitors

NASA's Gravity Recovery and Climate Experiment (GRACE) satellites measure time variations of the Earth's gravity field enabling reliable detection of spatio-temporal variations in total terrestrial water storage (TWS), including groundwater. The U.S. and North American Drought Monitors rely heavily on precipitation indices and do not currently incorporate systematic observations of deep soil moisture and groundwater storage conditions. Thus GRACE has great potential to improve the Drought Monitors by filling this observational gap. GRACE TWS data were assimilating into the Catchment Land Surface Model using an ensemble Kalman smoother enabling spatial and temporal downscaling and vertical decomposition into soil moisture and groundwater components. The Drought Monitors combine several short- and long-term drought indicators expressed in percentiles as a reference to their historical frequency of occurrence. To be consistent, we generated a climatology of estimated soil moisture and ground water based on a 60-year Catchment model simulation, which was used to convert seven years of GRACE assimilated fields into drought indicator percentiles. At this stage we provide a preliminary evaluation of the GRACE assimilated moisture and indicator fields.

Houborg, Rasmus↗
NASA NTRS2015

Signal Processing for Determining Water Height in Steam Pipes with Dynamic Surface Conditions

An enhanced signal processing method based on the filtered Hilbert envelope of the auto-correlation function of the wave signal has been developed to monitor the height of condensed water through the steel wall of steam pipes with dynamic surface conditions. The developed signal processing algorithm can also be used to estimate the thickness of the pipe to determine the cut-off frequency for the low pass filter frequency of the Hilbert Envelope. Testing and analysis results by using the developed technique for dynamic surface conditions are presented. A multiple array of transducers setup and methodology are proposed for both the pulse-echo and pitch-catch signals to monitor the fluctuation of the water height due to disturbance, water flow, and other anomaly conditions.

health monitoring↗
DOE OSTI2015

Monitoring Streambed Scour/Deposition Using Non-Sinusoidal Water Temperature Signals and During Flood Events

Streambed erosion and deposition are inherent to river beds, and monitoring their evolution is important for ecological system management and instream infrastructure stability. The thermal scour-deposition chain (TSDC) is a novel tool capable of simultaneously monitoring scour and deposition, stream sediment thermal regime, and seepage velocity information, but previous research did not address non-sinusoidal temperature variations and natural flooding conditions. Laboratory tests show the TSDC is equally capable of measuring scour-deposition sequences and seepage velocity using sinusoidal and non-sinusoidal temperature signals under a range of seepage velocities. Application in a dam release stream during flood condition shows excellent match between surveyed and TSDC-monitored bed elevation changes and provides useful seepage velocity information even under very low temperature signal amplitudes. Future research should focus on improved techniques for temperature signal phase and amplitude extractions, as well as TSDC application to monitor scour at bridge piers and abutments.

streambed erosion, ecological system management↗