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At least 739 records · Page 41Linked to original sources
USGS2011

Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use

The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ∼1200 km south of Manzala. Freshwater wetland plants that were dominant, such as Typha and Phragmites , decreased rapidly, whereas in the early 1900s, brackish water wetland species ( e.g. , Amaranthaceae) increased. This change occurred after closure of the Aswan Low Dam in 1902. The second major modification in the pollen record occurred in the early 1970s, after Aswan High Dam closure from 1965 to 1970, when Typha pollen abundance increased rapidly. Massive population growth occurred along the Nile during the 130 years represented by the core section. During this time, the total volume of lagoon water decreased because of conversion of wetland areas to agricultural land, and input of organic-rich sediment, sewage (municipal, agricultural, industrial), and fertilizer in Manzala lagoon increased markedly. Although the wetland plant community has continued to respond to increasingly intensified and varied human-induced pressures in proximal sectors, the two most marked changes in Manzala pollen best correlate with distal events ( i.e. , closure of the two dams at Aswan). The study also shows that the two major vegetation changes in Manzala lagoon each occurred less than 10 years after closure upriver of the Low and High dams that markedly altered the Nile regime from Upper Egypt to the coast.

Manzala Lagoon↗
USGS2023

Carbonate chemistry and carbon sequestration driven by inorganic carbon outwelling from mangroves and saltmarshes

Mangroves and saltmarshes are biogeochemical hotspots storing carbon in sediments and in the ocean following lateral carbon export (outwelling). Coastal seawater pH is modified by both uptake of anthropogenic carbon dioxide and natural biogeochemical processes, e.g., wetland inputs. Here, we investigate how mangroves and saltmarshes influence coastal carbonate chemistry and quantify the contribution of alkalinity and dissolved inorganic carbon (DIC) outwelling to blue carbon budgets. Observations from 45 mangroves and 16 saltmarshes worldwide revealed that >70% of intertidal wetlands export more DIC than alkalinity, potentially decreasing the pH of coastal waters. Porewater-derived DIC outwelling (81 ± 47 mmol m −2 d −1 in mangroves and 57 ± 104 mmol m −2 d −1 in saltmarshes) was the major term in blue carbon budgets. However, substantial amounts of fixed carbon remain unaccounted for. Concurrently, alkalinity outwelling was similar or higher than sediment carbon burial and is therefore a significant but often overlooked carbon sequestration mechanism.

Nature↗
USGS2024

Seasonal and spatial patterns in sediment transport in an erosional marsh system

Salt marshes provide expansive ecosystem services to coastal regions, including serving as bird and fish habitat, providing flood protection, and sequestering carbon and toxins (Barbier et al. 2011). While marshes are naturally dynamic, they are undergoing net loss in the 21st century largely due to lateral erosion (Camp- bell et al. 2022). In regions where marsh migration is constrained by built infrastructure, or where sediment resources may be insufficient for vertical or lateral expansion, approaches to prevent net marsh loss against lateral erosion are limited. To better understand and strategize around these conditions, detailed studies of marsh-edge loss mechanisms and their connections to sediment transport dynamics are necessary (Smith et al. 2021).

California↗
USGS2002

Relationships between streambed substrate characteristics and freshwater mussels (Bivalvia: Unionidae) in coastal plain streams

Freshwater mussels and stream substrate were sampled at 30 locations in the Apalachicola, Chattahoochee, and Flint (ACF) river basins. Although >2100 mussels that included 25 species were observed in our sample of 2661 quadrats, only 5 species were sufficiently abundant to provide reliable estimates of the relationship between mussel presence and substrate composition. Among these 5 species, only Villosa lienosa was associated with substrate composition. Villosa lienosa was most prevalent in well-sorted sediments that contained high proportions of fine particles, but its presence was unrelated to sediment porosity. Because many species of freshwater mussels in these Coastal Plain streams are dispersed and rare, future studies of mussel–habitat associations in the ACF basin should include novel sampling designs and methods that allow rare species to be encountered in greater numbers than those observed in our study.

Alabama, Florida, Georgia↗
USGS2020

A classification of streamflow patterns across the coastal Gulf of Alaska

Streamflow controls many freshwater and marine processes, including salinity profiles, sediment composition, fluxes of nutrients, and the timing of animal migrations. Watersheds that border the Gulf of Alaska (GOA) comprise over 400,000 km 2 of largely pristine freshwater habitats and provide ecosystem services such as reliable fisheries for local and global food production. Yet no comprehensive watershed-scale description of current temporal and spatial patterns of streamflow exists within the coastal GOA. This is an immediate need because the spatial distribution of future streamflow patterns may shift dramatically due to warming air temperature, increased rainfall, diminishing snowpack, and rapid glacial recession. Our primary goal was to describe variation in streamflow patterns across the coastal GOA using an objective set of descriptors derived from flow predictions at the downstream-most point within each watershed. We leveraged an existing hydrologic runoff model and Bayesian mixture model to classify 4,140 watersheds into 13 classes based on seven streamflow statistics. Maximum discharge timing (annual phase shift) and magnitude relative to mean discharge (amplitude) were the most influential attributes. Seventy-six percent of watersheds by number showed patterns consistent with rain or snow as dominant runoff sources, while the remaining watersheds were driven by rain-snow, glacier, or low-elevation wetland runoff. Streamflow classes exhibited clear mechanistic links to elevation, ice coverage, and other landscape features. Our classification identifies watersheds that might shift streamflow patterns in the near future and, importantly, will help guide the design of studies that evaluate how hydrologic change will influence coastal GOA ecosystems.

Alaska↗
USGS2006

High-resolution geologic mapping of the inner continental shelf: Nahant to Gloucester, Massachusetts

This report presents high-resolution maps of the seafloor offshore of Massachusetts, from Nahant to Gloucester. Approximately 134 km² of the inner shelf were mapped with a focus on the nearshore region in water depths less than 40 m (fig. 1.1). The maps were prepared as part of a cooperative mapping program between the U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management (CZM). They are based on marine geophysical data, sediment sampling, and bottom photography obtained on two research cruises carried out in 2003 and 2004. The primary objective of this program is to develop a suite of seafloor maps that provide geologic information for management of coastal and marine resources. Accurate maps of seafloor geology are important first steps toward protecting fish habitat, delineating marine reserves, and assessing environmental changes due to natural or human impacts. The maps also provide a geologic framework for scientific research, industry and the public. The organization of this report is outlined in the navigation bar along the left-hand margin of the page. This is section 1, the introduction. Section 2 briefly describes the mapping products contained in this report and has links to large-format map sheets, that can be viewed on line or downloaded. Section 3 is a description of the data collection, processing, and analysis procedures used to create the map products. Section 4 examines the geologic framework and late Quaternary evolution of the region, and presents two different strategies for mapping the complex seafloor. This report also contains four appendices that include GIS layers of all data collected in this study, and copies of the sample and photographic data used to validate the interpretations.

Massachusetts↗
USGS1992

Effect of rising sea level on runoff and groundwater discharge to coastal ecosystems

Rising sea level can cause an increase in surface runoff from coastal areas by raising the watertable and thus increasing the incidence of saturated soil conditions in low-lying areas. As surface runoff increases, less rainfall will infiltrate into the ground and groundwater discharge to the coast will decrease. The link between sea level rise and runoff is critically dependent on the sensitivity of surface runoff to changes in the elevation of the watertable. A significant relation between the two is demonstrated for a coastal watershed on Cape Cod, where it is estimated that a 10 cm rise in the watertable will increase surface runoff by 70% and decrease groundwater discharge by 20%. Effects on near-shore ecosystems include changes in nutrient fluxes and in the salinity of the sediments.

Estuarine, Coastal and Shelf Science↗
USGS2025

Site response and wave propagation effects in the eastern United States

Fourier amplitude spectra from regional earthquakes in the eastern United States are used in a parametric inversion for source, path, and site effects. Five earthquakes are selected for analysis during the installation of the United States National Seismic Network (US), Earthscope’s USArray Transportable Array (TA), and other temporary arrays to maximize station coverage. A global search algorithm is used to solve for site response from 0.1 to 15 Hz, corner frequency, geometrical spreading ( r - γ ), and frequency dependent anelastic attenuation in the form Q(f) = Q o f α . Tradeoff between moment and geometric spreading is handled by fixing the moment. The tradeoff between corner frequency and Q(f) is solved by selecting the value of corner frequency that minimizes an objective function defined over all stations. Values of site response and attenuation parameters show a strong spatial correlation with the physiographic provinces of the eastern United States. Site response for the Atlantic Coastal Plain is consistent with previous work using spectral ratios relative to a reference site, defined by strong resonance peaks correlated with the thickness of sediments. Site response for the other physiographic provinces is markedly different from the coastal plain, with a lack of distinct resonance peaks and a broad moderate high at frequences from 0.1 to 0.5 Hz consistent with the hard-rock geology of the regions. Like site response, Q(f) has a strong correlation with physiographic province, showing lower values on the coastal plain and higher values inland. Geometric spreading exponent, γ, decreases with increasing hypocenter distance from just above 1 at a few tens of kilometers to 0.9 at 500 km. The limited range in geometric spreading values is attributed to starting the Fourier transform window at the S ‐wave arrival for all distances and averaging over multiple wave types.

eastern United States↗
USGS1991

Late Quaternary stratigraphy and depositional history of the Long Island Sound basin

The stratigraphy of Late Quaternary geologic units beneath Long Island Sound (LIS) is interpreted from 3,500 km of high-resolution, seismic-reflection profiles supplemented by vibracore data. Knowledge gained from onshore regional geologic studies and previous offshore investigations is also incorporated in these interpretations. Glacial deposits overlie and nearly fill an Inner Lowland which is floored by crystalline rocks in the north and bounded to the south by an irregular, north-facing cuesta scarp in Cretaceous Coastal-Plain strata. The thick glacial section consists largely of sediment that was deposited in glacial Lake Connecticut during the retreat of the last (late Wisconsin) ice sheet. Ice-marginal lacustrine fan deposits and submerged extensions of the southeastern Connecticut recessional moraines mark positions of the ice margin during systematic northward retreat. When the ice margin stood at positions just north of the present shoreline of Connecticut (17.6-16.5 ka), glacial Lake Connecticut was slightly larger than Long Island Sound is today. Ice-marginal deltas and near-ice marginal fluviodeltaic deposits occur along coastal Connecticut. Delta-building was diachronous; progressively younger deltas record northwesterly retreat of the ice margin and lowering lake levels. Distally from the deltas, varied lake-clays (up to 150 m thick) drape the underlying topography. The lake spillway cut across the Harbor Hill-Roanoke Point-Fishers Island-Charlestown end moraine at its lowest point just west of Fishers Island (The Race). Lake levels fell as the spillway notch was erosionally deepened, and gradually the lakebed became subaerially exposed. A largely preserved channel system cuts the lake-deposit surface; fluvial channel-fill sediments are overlain by estuarine sediments in the channel system. Perhaps as early as 15 ka, but no later than 13 ka, the sea entered the Basin through the channel at The Race and quickly transgressed westward via the lakebed channel system. As the sea rose further and spread throughout the Basin, a wave-cut surface was formed. Extensive marine deltaic deposits, up to 40 m thick, overlie the wave-cut marine unconformity in the east-central part of the Basin. These sediments were derived from erosion of the drained bed of Lake Hitchcock, in the Connecticut valley to the north, and were deposited in a -40-m relative sea at about 12.4 ka. Where quiet waters prevail, marine mud generally less than 15 m thick blankets the older deposits of the Basin. Elsewhere, especially in eastern LIS, tidal currents are actively reworking and transporting glacial and postglacial deposits.

Connecticut, New York↗
USGS2011

Geomorphology of the Elwha River and its Delta: Chapter 3 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

The removal of two dams on the Elwha River will introduce massive volumes of sediment to the river, and this increase in sediment supply in the river will likely modify the shapes and forms of the river and coastal landscape downstream of the dams. This chapter provides the geologic and geomorphologic background of the Olympic Peninsula and the Elwha River with emphasis on the present river and shoreline. The Elwha River watershed was formed through the uplift of the Olympic Mountains, erosion and movement of sediment throughout the watershed from glaciers, and downslope movement of sediment from gravitational and hydrologic forces. Recent alterations to the river morphology and sediment movement through the river include the two large dams slated to be removed in 2011, but also include repeated bulldozing of channel boundaries, construction and maintenance of flood plain levees, a weir and diversion channel for water supply purposes, and engineered log jams to help enhance river habitat for salmon. The shoreline of the Elwha River delta has changed in location by several kilometers during the past 14,000 years, in response to variations in the local sea-level of approximately 150 meters. Erosion of the shoreline has accelerated during the past 80 years, resulting in landward movement of the beach by more than 200 meters near the river mouth, net reduction in the area of coastal wetlands, and the development of an armored low-tide terrace of the beach consisting primarily of cobble. Changes to the river and coastal morphology during and following dam removal may be substantial, and consistent, long-term monitoring of these systems will be needed to characterize the effects of the dam removal project.

Washington↗
USGS2008

Slowing of coastal subsidence is good news for restoration of Louisiana's wetlands

Every year, volunteers use thousands of discarded Christmas trees to build brush fences in the coastal waters of Louisiana. The fences slow down waves and trap sediment, allowing aquatic vegetation to take root in the still water and stimulating the growth of new marsh. This is one of many efforts to counteract wetland loss (the loss of saline, brackish, intermediate, and freshwater marshes) that has plagued coastal Louisiana since the mid-20th century. U.S. Geological Survey (USGS) scientists recently announced good news for Louisiana's coastal-restoration projects: using a combination of historical and recently released data, they discovered that subsidence of coastal land in the Mississippi River delta plain appears to have slowed considerably since the 1990s. This discovery means that new marshlands created by the Christmas tree program and other restoration projects may persist—that is, stay above sea level—longer than previously thought.

Louisiana↗
USGS2007

Ecology of tidal freshwater forests in coastal deltaic Louisiana and northeastern South Carolina: Chapter 9

Tidal freshwater swamps in the southeastern United States are subjected to tidal hydroperiods ranging in amplitude from microtidal (<0.1 m) to mesotidal (2-4 m), both having different susceptibilities to anthropogenic change. Small alterations in flood patterns, for example, can switch historically microtidal swamps to permanently flooded forests, scrub-shrub stands, marsh, or open water but are less likely to convert mesotidal swamps. Changes to hydrological patterns tend to be more noticeable in Louisiana than do those in South Carolina. The majority of Louisiana’s coastal wetland forests are found in the Mississippi River deltaic plain region. Coastal wetland forests in the deltaic plain have been shaped by the sediments, water, and energy of the Mississippi River and its major distributaries. Baldcypress ( Taxodium distichum [L.] L.C. Rich.) and water tupelo ( Nyssa aquatica L.) are the primary tree species in the coastal swamp forests of Louisiana. Sites where these species grow usually hold water for most of the year; however, some of the more seaward sites were historically microtidal, especially where baldcypress currently dominates. In many other locations, baldcypress and water tupelo typically grow in more or less pure stands or as mixtures of the two with common associates such as black willow ( Salix nigra Marsh.), red maple ( Acer rubrum L.), water locust ( Gleditsia aquatic Marsh.), overcup oak ( Quercus lyrata Walt.), water hickory ( Carya aquatica [Michx. f.] Nutt.), green ash ( Fraxinus pennsylvanica Marsh.), pumpkin ash (F. profunda Bush.), and redbay ( Persea borbonia [L.] Sprengel) (Brown and Montz 1986). The South Carolina coastal plain occupies about two-thirds of the state and rises gently to 150 m from the Atlantic Ocean up to the Piedmont plateau. Many rivers can be found in the Coastal Plain with swamps near the coast that extend inland along the rivers. Strongly tidal freshwater forests occur along the lower reaches of redwater rivers (Santee, Great Pee Dee, and Savannah) that arise in the mountains and along the numerous blackwater rivers (Ashepoo, Combahee, Cooper, and Waccamaw) that arise in the coastal regions. Most of the tidal freshwater forests were converted to tidal rice fields in the 1700s (Porcher 1995). Canopy members of the present day forests include baldcypress, water tupelo, swamp tupelo ( N. biflora Walt.), red maple, and Carolina ash ( Fraxinus caroliniana Miller). Subcanopy and shrub species include Virginia sweetspire ( Itea virginica L.), dwarf palmetto ( Sabal minor (Jacquin) Pers.), coastal plain willow ( Salix caroliniana Michx.), redbay, and water-elm ( Planera aquatica Gmel.).

Louisiana, South Carolina↗
USGS1994

Sediment-transport events on the northern California continental shelf during the 1990-1991 STRESS experiment

Measurements of currents and light transmission were made at bottom tripods and moorings arrayed across the northern California continental shelf along the Coastal Ocean Dynamics Experiment (CODE) "C" transect as part of the 1990-1991 Sediment Transport Events on Shelves and Slopes (STRESS) experiment. In combination with meteorological and wave data from the National Data Buoy Center Buoy 46013, these measurements provide information about the physical forcing and resultant resuspension and transport of bottom material between 21 November and 8 March. Sixteen events were identified in the wave, wind and current-meter records for this period. Only two were local storms with southerly winds, but they caused about half of the seasonal net transport. Seven were swell events that combined long-period waves generated by distant storms with local currents. At the 90-m site, swells interacted with the mean northward flow to produce northward transport. During six northerly wind events, upwelling-favorable winds often were sufficient to slow or reverse the mean northward flow and thus caused southward transport. A single current event, which produced moderate southward transport, was observed at the 130-m site. Net transport during the winter experiment was offshore at all sites, northward at the inner- and mid-shelf sites, but southward at the outer-shelf site. The results suggest that local storms with southerly winds may dominate seasonal transport, as on the Washington shelf, but significant transport also can occur during fair weather and during periods of northerly winds. ?? 1994.

Continental Shelf Research↗
USGS2018

The geomorphology of an Aleutian volcano following a major eruption: The 7-8 August 2008 eruption of Kasatochi Volcano, Alaska, and its aftermath

Analysis of satellite images of Kasatochi volcano and field studies in 2008 and 2009 have shown that within about one year of the 78 August 2008 eruption, significant geomorphic changes associated with surface and coastal erosion have occurred. Gully erosion has removed 300,000 to 600,000 m3 of mostly fine-grained volcanic sediment from the flanks of the volcano and much of this has reached the ocean. Sediment yield estimates from two representative drainage basins on the south and west flanks of the volcano, with drainage areas of 0.7 and 0.5 km2, are about 104 m3 km-2 yr-1 and are comparable to sediment yields documented at other volcanoes affected by recent eruptive activity. Estimates of the retreat of coastal cliffs also made from analysis of satellite images indicate average annual erosion rates of 80 to 140 m yr-1. If such rates persist it could take 35 years for wave erosion to reach the pre-eruption coastline, which was extended seaward about 400 m by the accumulation of erupted volcanic material. As of 13 September 2009, the date of the most recent satellite image of the island, the total volume of material eroded by wave action was about 106 m3. We did not investigate the distribution of volcanic sediment in the near shore ocean around Kasatochi Island, but it appears that erosion and sediment dispersal in the nearshore environment will be greatest during large storms when the combination of high waves and rainfall runoff are most likely to coincide. ?? 2010 Regents of the University of Colorado.

Arctic, Antarctic, and Alpine Research↗
USGS2016

Decoupling processes and scales of shoreline morphodynamics

Behavior of coastal systems on time scales ranging from single storm events to years and decades is controlled by both small-scale sediment transport processes and large-scale geologic, oceanographic, and morphologic processes. Improved understanding of coastal behavior at multiple time scales is required for refining models that predict potential erosion hazards and for coastal management planning and decision-making. Here we investigate the primary controls on shoreline response along a geologically-variable barrier island on time scales resolving extreme storms and decadal variations over a period of nearly one century. An empirical orthogonal function analysis is applied to a time series of shoreline positions at Fire Island, NY to identify patterns of shoreline variance along the length of the island. We establish that there are separable patterns of shoreline behavior that represent response to oceanographic forcing as well as patterns that are not explained by this forcing. The dominant shoreline behavior occurs over large length scales in the form of alternating episodes of shoreline retreat and advance, presumably in response to storms cycles. Two secondary responses include long-term response that is correlated to known geologic variations of the island and the other reflects geomorphic patterns with medium length scale. Our study also includes the response to Hurricane Sandy and a period of post-storm recovery. It was expected that the impacts from Hurricane Sandy would disrupt long-term trends and spatial patterns. We found that the response to Sandy at Fire Island is not notable or distinguishable from several other large storms of the prior decade.

New York↗
USGS2002

Climate change impacts on U.S. coastal and marine ecosystems

Increases in concentrations of greenhouse gases projected for the 21st century are expected to lead to increased mean global air and ocean temperatures. The National Assessment of Potential Consequences of Climate Variability and Change (NAST 2001) was based on a series of regional and sector assessments. This paper is a summary of the coastal and marine resources sector review of potential impacts on shorelines, estuaries, coastal wetlands, coral reefs, and ocean margin ecosystems. The assessment considered the impacts of several key drivers of climate change: sea level change; alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment; increased ocean temperature; alterations in circulation patterns; changes in frequency and intensity of coastal storms; and increased levels of atmospheric CO 2 . Increasing rates of sea-level rise and intensity and frequency of coastal storms and hurricanes over the next decades will increase threats to shorelines, wetlands, and coastal development. Estuarine productivity will change in response to alteration in the timing and amount of freshwater, nutrients, and sediment delivery. Higher water temperatures and changes in freshwater delivery will alter estuarine stratification, residence time, and eutrophication. Increased ocean temperatures are expected to increase coral bleaching and higher CO 2 levels may reduce coral calcification, making it more difficult for corals to recover from other disturbances, and inhibiting poleward shifts. Ocean warming is expected to cause poleward shifts in the ranges of many other organisms, including commercial species, and these shifts may have secondary effects on their predators and prey. Although these potential impacts of climate change and variability will vary from system to system, it is important to recognize that they will be superimposed upon, and in many cases intensify, other ecosystem stresses (pollution, harvesting, habitat destruction, invasive species, land and resource use, extreme natural events), which may lead to more significant consequences.

Estuaries↗
USGS2008

Development of a three-dimensional, regional, coupled wave, current, and sediment-transport model

We are developing a three-dimensional numerical model that implements algorithms for sediment transport and evolution of bottom morphology in the coastal-circulation model Regional Ocean Modeling System (ROMS v3.0), and provides a two-way link between ROMS and the wave model Simulating Waves in the Nearshore (SWAN) via the Model-Coupling Toolkit. The coupled model is applicable for fluvial, estuarine, shelf, and nearshore (surfzone) environments. Three-dimensional radiation-stress terms have been included in the momentum equations, along with effects of a surface wave roller model. The sediment-transport algorithms are implemented for an unlimited number of user-defined non-cohesive sediment classes. Each class has attributes of grain diameter, density, settling velocity, critical stress threshold for erosion, and erodibility constant. Suspended-sediment transport in the water column is computed with the same advection-diffusion algorithm used for all passive tracers and an additional algorithm for vertical settling that is not limited by the CFL criterion. Erosion and deposition are based on flux formulations. A multi-level bed framework tracks the distribution of every size class in each layer and stores bulk properties including layer thickness, porosity, and mass, allowing computation of bed morphology and stratigraphy. Also tracked are bed-surface properties including active-layer thickness, ripple geometry, and bed roughness. Bedload transport is calculated for mobile sediment classes in the top layer. Bottom-boundary layer submodels parameterize wave-current interactions that enhance bottom stresses and thereby facilitate sediment transport and increase bottom drag, creating a feedback to the circulation. The model is demonstrated in a series of simple test cases and a realistic application in Massachusetts Bay.

Computers & Geosciences↗
USGS2014

Studying seafloor bedforms using autonomous stationary imaging and profiling sonars

The Sediment Transport Group at the U.S. Geological Survey, Woods Hole Coastal and Marine Science Center uses downward looking sonars deployed on seafloor tripods to assess and measure the formation and migration of bedforms. The sonars have been used in three resolution-testing experiments, and deployed autonomously to observe changes in the seafloor for up to two months in seven field experiments since 2002. The sonar data are recorded concurrently with measurements of waves and currents to: a) relate bedform geometry to sediment and flow characteristics; b) assess hydrodynamic drag caused by bedforms; and c) estimate bedform sediment transport rates, all with the goal of evaluating and improving numerical models of these processes. Our hardware, data processing methods, and test and validation procedures have evolved since 2001. We now employ a standard sonar configuration that provides reliable data for correlating flow conditions with bedform morphology. Plans for the future are to sample more rapidly and improve the precision of our tripod orientation measurements.

Conference Paper↗