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At least 325 records · Page 18Linked to original sources
USGS1983

Acoustic systems for the measurement of streamflow

The acoustic velocity meter (AVM), also referred to as an ultrasonic flowmeter, has been an operational tool for the measurement of streamflow since 1965. Very little information is available concerning AVM operation, performance, and limitations. The purpose of this report is to consolidate information in such a manner as to provide a better understanding about the application of this instrumentation to streamflow measurement. AVM instrumentation is highly accurate and nonmechanical. Most commercial AVM systems that measure streamflow use the time-of-travel method to determine a velocity between two points. The systems operate on the principle that point-to-point upstream travel-time of sound is longer than the downstream travel-time, and this difference can be monitored and measured accurately by electronics. AVM equipment has no practical upper limit of measurable velocity if sonic transducers are securely placed and adequately protected. AVM systems used in streamflow measurement generally operate with a resolution of ?0.01 meter per second but this is dependent on system frequency, path length, and signal attenuation. In some applications the performance of AVM equipment may be degraded by multipath interference, signal bending, signal attenuation, and variable streamline orientation. Presently used minicomputer systems, although expensive to purchase and maintain, perform well. Increased use of AVM systems probably will be realized as smaller, less expensive, and more conveniently operable microprocessor-based systems become readily available. Available AVM equipment should be capable of flow measurement in a wide variety of situations heretofore untried. New signal-detection techniques and communication linkages can provide additional flexibility to the systems so that operation is possible in more river and estuary situations.

Water Supply Paper↗
USGS2026

Seasonal and annual survival of acoustically tagged juvenile Gulf sturgeon in the Apalachicola River, Florida, USA

Gulf sturgeon Acipenser desotoi are anadromous fish that have undergone major population declines throughout their range. Habitat alteration and previous overharvest in commercial fisheries led to the species being listed as ‘threatened’ under the US Endangered Species Act in 1991. An accurate understanding of population dynamics, including survival, is necessary for monitoring population trends and recovery. Juvenile Gulf sturgeon are migratory within their natal river system; their survival is not well-studied, but their over-winter occupation of more saline habitat has been identified as a potential bottleneck to juvenile survival. Therefore, we estimated over-winter and annual survival of juvenile Gulf sturgeon in the Apalachicola River system (Florida, USA) using Cormack-Jolly-Seber models informed by acoustic telemetry data from 2014-2023. Seasonal apparent survival estimates ranged from 0.96 in the fall to 0.99 in the spring. Contrary to our expectation, results indicated that survival was high across all seasons with no notable difference in over-winter survival compared to other periods. We also estimated apparent annual survival to be 0.76 for juvenile Gulf sturgeon in the system. These findings suggest that over-winter juvenile mortality is not a major bottleneck to Gulf sturgeon population recovery within the Apalachicola River.

Florida↗
USGS2021

Can identifying discrete behavioral groups with individual-based acoustic telemetry advance the understanding of fish distribution patterns?

Identifying patterns of organismal distribution can provide valuable insights for basic and applied marine and coastal ecology because understanding where animals are located is foundational to both research and science-based conservation. Understanding variation in distributional patterns can lead to a better assessment of ecological drivers and an improved ability to predict consequences of natural and altered relationships. Here, our purpose is to explore if quantifying coexisting groups of individual fish predators advances our understanding of field distribution patterns. Toward this end, we quantified locations of 59 acoustically tagged striped bass ( Morone saxatilis) within a 26-stationary unit telemetry receiver array in Plum Island Estuary (PIE), MA, United States. We then used cluster analyses on spatial and temporal-spatial metrics from this dataset to (1) assess if distinct groups of individuals coexisted, (2) quantify group characteristics, and (3) test associations between groups and distribution (e.g., physical site type and region). Based on multiple lines of evidence, we identified four groups of striped bass with different space use patterns that persisted across seasons (summer and fall). Similar-sized striped bass clustered at spatial and temporal scales at which individuals within distinct groups could, and did, physically overlap. In addition, distributional groups were linked to components of physical site type and region suggesting that discrete groups of individuals can interact differently with the environment within the same ecological system. The identification of these distinct groups of individuals creates a baseline from which to explore further ecological implications of grouping behavior for research and conservation in geographically large, temporally dynamic, and spatially heterogeneous marine and coastal environments.

Massachusetts↗
USGS2021

Monitoring and modeling tree bat (Genera: Lasiurus, Lasionycteris) occurrence using acoustics on structures off the mid-Atlantic coast—Implications for offshore wind development

In eastern North America, “tree bats” (Genera: Lasiurus and Lasionycteris ) are highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. This raises concern about ongoing expansion of offshore wind-energy development off the Atlantic Coast. Season, atmospheric conditions, and site-level characteristics such as local habitat (e.g., forest coverage) have been shown to influence wind turbine collision rates by bats onshore, and therefore may be related to risk offshore. Therefore, to assess the factors affecting coastal presence of bats, we continuously gathered tree bat occurrence data using stationary acoustic recorders on five structures (four lighthouses on barrier islands and one light tower offshore) off the coast of Virginia, USA, across all seasons, 2012–2019. We used generalized additive models to describe tree bat occurrence on a nightly basis. We found that sites either indicated maternity or migratory seasonal occurrence patterns associated with local roosting resources, i.e., presence of trees. Across all sites, nightly occurrence was negatively related to wind speed and positively related to temperature and visibility. Using predictive performance metrics, we concluded that our model was highly predictive for the Virginia coast. Our findings were consistent with other studies—tree bat occurrence probability and presumed mortality risk to offshore wind-energy collisions is highest on low wind speed nights, high temperature and visibility nights, and during spring and fall. The high predictive model performance we observed provides a basis for which managers, using a similar monitoring and modeling regime, could develop an effective curtailment-based mitigation strategy.

Virginia↗
USGS2018

Probabilistic substrate classification with multispectral acoustic backscatter: A comparison of discriminative and generative models

We propose a probabilistic graphical model for discriminative substrate characterization, to support geological and biological habitat mapping in aquatic environments. The model, called a fully-connected conditional random field (CRF), is demonstrated using multispectral and monospectral acoustic backscatter from heterogeneous seafloors in Patricia Bay, British Columbia, and Bedford Basin, Nova Scotia. Unlike previously proposed discriminative algorithms, the CRF model considers both the relative backscatter magnitudes of different substrates and their relative proximities. The model therefore combines the statistical flexibility of a machine learning algorithm with an inherently spatial treatment of the substrate. The CRF model predicts substrates such that nearby locations with similar backscattering characteristics are likely to be in the same substrate class. The degree of allowable proximity and backscatter similarity are controlled by parameters that are learned from the data. CRF model results were evaluated against a popular generative model known as a Gaussian Mixture model (GMM) that doesn’t include spatial dependencies, only covariance between substrate backscattering response over different frequencies. Both models are used in conjunction with sparse bed observations/samples in a supervised classification. A detailed accuracy assessment, including a leave-one-out cross-validation analysis, was performed using both models. Using multispectral backscatter, the GMM model trained on 50% of the bed observations resulted in a 75% and 89% average accuracies in Patricia Bay and Bedford Basin, respectively. The same metrics for the CRF model were 78% and 95%. Further, the CRF model resulted in a 91% mean cross-validation accuracy across four substrate classes at Patricia Bay, and a 99.5% mean accuracy across three substrate classes at Bedford Basin, which suggest that the CRF model generalizes extremely well to new data. This analysis also showed that the CRF model was much less sensitive to the specific number and locations of bed observations than the generative model, owing to its ability to incorporate spatial autocorrelation in substrates. The CRF therefore may prove to be a powerful ‘spatially aware’ alternative to other discriminative classifiers.

Geosciences↗
USGS2023

Application of electricity and underwater acoustics to clear fish from a navigation lock during maintenance

The presence of fish within navigation locks can introduce an environmental challenge for construction crews when maintenance is required. This study examined the effectiveness of a dual-deterrent fish herding technique using electricity and acoustic stimuli to reduce the abundance of fish within a navigation lock before a scheduled dewatering for maintenance. Fixed-location multi-beam imaging sonar was used to evaluate fish per minute (FPM) detections near the lock entrance before, during, and after the herding effort. Standardized mobile side-scan sonar surveys were also conducted before and after the herding to examine fish presence throughout the entire lock. Collectively, a 73% reduction in fish targets detected by side-scan sonar and a 43% reduction in FPM detected by imaging sonar were observed following the herding technique. Post-fish herding, 88% reduction in FPM >400mm and a 35% reduction in FPM <400mm were observed. Fish abundance within the lock chamber was reduced and did not result in construction delays, which was problematic and costly during previous dewatering events. Since data from this study are limited to a single lock dewatering and fish clearing event, caution should be taken with the extrapolation of these results. However, the applied methods show promise and may inform future fish clearing efforts to aid lock maintenance.

Illinois↗
USGS1998

Lake bed classification using acoustic data

As part of our effort to identify the lake bed surficial substrates using remote sensing data, this work designs pattern classifiers by multivariate statistical methods. Probability distribution of the preprocessed acoustic signal is analyzed first. A confidence region approach is then adopted to improve the design of the existing classifier. A technique for further isolation is proposed which minimizes the expected loss from misclassification. The devices constructed are applicable for real-time lake bed categorization. A mimimax approach is suggested to treat more general cases where the a priori probability distribution of the substrate types is unknown. Comparison of the suggested methods with the traditional likelihood ratio tests is discussed.

Applied Mathematics and Computer Science↗
USGS1985

APPLICATIONS OF BOREHOLE-ACOUSTIC METHODS IN ROCK MECHANICS.

Acoustic-logging methods using a considerable range of wavelengths and frequencies have proven very useful in the in situ characterization of deeply buried crystalline rocks. Seismic velocities are useful in investigating the moduli of unfractured rock, and in producing a continuous record of rock quality for comparison with discontinuous intervals of core. The considerable range of frequencies makes the investigation of scale effects possible in both fractured and unfractured rock. Several specific methods for the characterization of in situ permeability have been developed and verified in the field.

Conference Paper↗
USGS1990

Acoustic Doppler discharge-measurement system

A discharge-measurement system that uses a vessel-mounted acoustic Doppler current profiler has been developed and tested by the U.S. Geological Survey. Discharge measurements using the system require a fraction of the time needed for conventional current-meter discharge measurements and do not require shore-based navigational aids or tag lines for positioning the vessel.

Conference Paper↗
USGS1994

Recent applications of acoustic Doppler current profilers

A Broadband acoustic Doppler current profiler (BB-ADCP) is a new instrument being used by the U.S. Geological Survey (USGS) to measure stream discharge and velocities, and bathymetry. During the 1993 Mississippi River flood, more than 160 high-flow BB-ADCP measurements were made by the USGS at eight locations between Quincy and Cairo, Ill., from July 19 to August 20, 1993. A maximum discharge of 31,400 m3/s was measured at St. Louis, Mo., on August 2, 1993. A BB-ADCP also has been used to measure leakage through three control structures near Chicago, Ill. These measurements are unusual in that the average velocity for the measured section was as low as 0.03 m/s. BB-ADCP's are also used in support of studies of scour at bridges. During the recent Mississippi River flood, BB-ADCP's were used to measure water velocities and bathymetry upstream from, next to, and downstream from bridge piers at several bridges over the Mississippi River. Bathymetry data were collected by merging location data from Global Positioning System (GPS) receivers, laser tracking systems, and depths measured by the BB-ADCP. These techniques for collecting bathymetry data were used for documenting the channel formation downstream from the Miller City levee break and scour near two bridges on the Mississippi River.

Conference Paper↗
USGS1994

Field performance of an acoustic scour-depth monitoring system

The Herbert C. Bonner Bridge over Oregon Inlet serves as the only land link between Bodie and Hatteras Islands, part of the Outer Banks of North Carolina. Periodic soundings over the past 30 years have documented channel migration, local scour, and deposition at several pilings that support the bridge. In September 1992, a data-collection system was installed to permit the off-site monitoring of scour at 16 bridge pilings. The system records channel-bed elevations at 15-minute intervals and transmits the data to a satellite receiver. A cellular phone connection also permits downloading and reviewing of the data as they are being collected. A digitally recording, acoustic fathometer is the main component of the system. In November 1993, current velocity, water-surface elevation, wave characteristics, and water temperature measuring instruments were also deployed at the site. Several performance problems relating to the equipment and to the harsh marine environment have not been resolved, but the system has collected and transmitted reliable scour-depth and water-level data.

Conference Paper↗
USGS2002

Use of an Acoustic Doppler Current Profiler (ADCP) to Measure Hypersaline Bidirectional Discharge

The U.S. Geological Survey measures the exchange of flow between the north and south parts of Great Salt Lake, Utah, as part of a monitoring program. Turbidity and bidirectional flow through the breach in the causeway that divides the lake into two parts makes it difficult to measure discharge with conventional streamflow techniques. An acoustic Doppler current profiler (ADCP) can be used to more accurately define the angles of flow and the location of the interface between the layers of flow. Because of the high salinity levels measured in Great Salt Lake (60-280 parts per thousand), special methods had to be developed to adjust ADCP-computed discharges for the increased speed of sound in hypersaline waters and for water entrained at the interface between flow layers.

Conference Paper↗
USGS2002

Measurement of Turbulence with Acoustic Doppler Current Profilers - Sources of Error and Laboratory Results

Acoustic Doppler current profilers (ADCPs) provide a promising method for measuring surface-water turbulence because they can provide data from a large spatial range in a relatively short time with relative ease. Some potential sources of errors in turbulence measurements made with ADCPs include inaccuracy of Doppler-shift measurements, poor temporal and spatial measurement resolution, and inaccuracy of multi-dimensional velocities resolved from one-dimensional velocities measured at separate locations. Results from laboratory measurements of mean velocity and turbulence statistics made with two pulse-coherent ADCPs in 0.87 meters of water are used to illustrate several of inherent sources of error in ADCP turbulence measurements. Results show that processing algorithms and beam configurations have important effects on turbulence measurements. ADCPs can provide reasonable estimates of many turbulence parameters; however, the accuracy of turbulence measurements made with commercially available ADCPs is often poor in comparison to standard measurement techniques.

Conference Paper↗
USGS2015

Using 15-minute acoustic data to analyze suspended-sediment dynamics in the Rio Grande in the Big Bend Region

The Rio Grande in the Big Bend region is subject to rapid geomorphic change consisting of channel narrowing during years of low flow, and channel widening during rare, large, long duration floods. Since the 1940s, there have been large declines in mean and peak stream flow, and the channel has progressively narrowed. Large, channel widening floods are infrequent and have failed to widen the channel to widths measured prior to the onset of channel narrowing in the 1940s. Before the most recent channel-widening flood in September 2008, the Rio Grande in the Big Bend was more than 50 percent narrower than measured in the 1940s. Channel narrowing results in increased flood frequency and flood magnitude due to the loss of channel capacity and flood conveyance (Dean and Schmidt, 2011). Channel narrowing also results in the loss of important aquatic habitats such as backwaters and side-channels, because these habitats accumulate sediment and are converted to floodplains. Environmental managers are attempting to construct an environmental flow program for the purposes of minimizing channel narrowing during low flow years such that channel capacity, flood conveyance, and important aquatic habitats are maintained. Effective mitigation of channel narrowing processes requires an in-depth understanding of the predominant sediment source areas, the quantity of sediment input from those source areas, the parts of the flow regime responsible for the greatest sediment deposition, and the effect of managed flows in ameliorating the sediment loading that occurs within the channel. Here, we analyze data collected with acoustic instrumentation at high temporal resolution to quantify suspended-sediment transport during a variety of flood types. We also investigate the effect of long duration managed flows in promoting sediment export and minimizing channel narrowing.

Rio Grande, Big Bend region↗
USGS2015

Suspended-sediment transport and storage: A demonstration of acoustic methods in the evaluation of reservoir management strategies for a small water-supply reservoir in western Colorado

The U.S. Bureau of Reclamation (USBR) and local stakeholder groups are evaluating reservoir-management strategies within Paonia Reservoir. This small reservoir fills to capacity each spring and requires approximately half of the snowmelt-runoff volume from its sediment-laden source waters, Muddy Creek. The U.S. Geological Survey is currently conducting high-resolution (15-minute data-recording interval) sediment monitoring to characterize incoming and outgoing sediment flux during reservoir operations at two sites on Muddy Creek. The high-resolution monitoring is being used to establish current rates of reservoir sedimentation, support USBR sediment transport and storage models, and assess the viability of water-storage recovery in Paonia Reservoir. These sites are equipped with in situ, single-frequency, side-looking acoustic Doppler current meters in conjunction with turbidity sensors to monitor sediment flux. This project serves as a demonstration of the capability of using surrogate techniques to predict suspended-sediment concentrations in small streams (less than 20 meters in width and 2 meters in depth). These two sites provide the ability to report near real-time suspended-sediment concentrations through the U.S. Geological Survey National Water Information System (NWIS) web interface and National Real-Time Water Quality websites (NRTWQ) to aid in reservoir operations and assessments.

Colorado↗
USGS2007

Cause and solution for false upstream boat velocities measured with a StreamPro acoustic doppler current profiler

In 2003, Teledyne RD Instruments introduced the StreamPro acoustic Doppler current profiler which does not include an internal compass. During stationary moving-bed tests the StreamPro often tends to swim or kite from the end of the tether (the instrument rotates then moves laterally in the direction of the rotation). Because the StreamPro does not have an internal compass, it cannot account for the rotation. This rotation and lateral movement of the StreamPro on the end of the tether generates a false upstream velocity, which cannot be easily distinguished from a moving-bed bias velocity. A field test was completed to demonstrate that this rotation and lateral movement causes a false upstream boat velocity. The vector dot product of the boat velocity and the unit vector of the depth-averaged water velocity is shown to be an effective method to account for the effect of the rotation and lateral movement.

Conference Paper↗
USGS2009

Temporal characteristics of coherent flow structures generated over alluvial sand dunes, Mississippi River, revealed by acoustic doppler current profiling and multibeam echo sounding

This paper investigates the flow in the lee of a large sand dune located at the confluence of the Mississippi and Missouri Rivers, USA. Stationary profiles collected from an anchored boat using an acoustic Doppler current profiler (ADCP) were georeferenced with data from a real-time kinematic differential global positioning system. A multibeam echo sounder was used to map the bathymetry of the confluence and provided a morphological context for the ADCP measurements. The flow in the lee of a low-angle dune shows good correspondence with current conceptual models of flow over dunes. As expected, quadrant 2 events (upwellings of low-momentum fluid) are associated with high backscatter intensity. Turbulent events generated in the lower lee of a dune near the bed are associated with periods of vortex shedding and wake flapping. Remnant coherent structures that advect over the lower lee of the dune in the upper portion of the water column, have mostly dissipated and contribute little to turbulence intensities. The turbulent events that occupy most of the water column in the upper lee of the dune are associated with periods of wake flapping.

Missouri↗
USGS2016

Acoustic surveys of Hawaiian Hoary Bats in Kahikinui Forest Reserve and Nakula Natural Area Reserve on the Island of Maui

The Kahikinui Forest Reserve and the adjoining Nakula Natural Area Reserve (KFR-NNAR) was established in 2011 as a conservation area on the leeward slope of Haleakalā Volcano on the island of Maui to protect unique natural features and endangered species including the Hawaiian hoary bat, Lasiurus cinereus semotus . We recorded bat vocalizations from July 2012 to November 2014 using automated echolocation detectors at 14 point locations in the KFRNNAR. Our study area included remnants of recovering mesic montane forest with interspersed grasses (1,250‒1,850 m elevation, hereafter called “forest”) and xeric subalpine shrubland plant communities (1,860‒2,800 m, hereafter called “shrubland”). Monthly detections of Hawaiian hoary bats, Lasiurus cinereus semotus , within the KFR-NNAR identified areas of high and low detection probability as well as foraging activity. Sixty per cent of all detector-nights had confirmed bat vocalizations and included detections in every month of the study. Monthly detection probability values were highest from July to November 2012; these values were significantly greater than values measured in any month thereafter. Pooled values of detection probabilities, mean pulses/night, percentage of nights with feeding activity, and acoustic detections all were greater in the recovering forest zone than corresponding values from the shrublands. Our data provide baseline levels of hoary bat echolocation activity that may be compared with future studies in the KFR-NNAR relative to success criteria for Hawaiian hoary bat habitat restoration.

Hawaii↗