Jessie Lacy
Research Oceanographer with the USGS Pacific Coastal and Marine Science Center
My research interests include: Hydrodynamics of the coastal ocean, estuaries, and lakes; Lateral dynamics in estuaries with complex topography, and their influence on mixing; The dynamics of stratification and baroclinic transport; Estimation of bottom roughness, bottom shear stress, and sediment resuspension in wave-dominated environments; Interaction between aquatic vegetation and hydrodynamics
Science and Products
Filter Total Items: 15
Wind-wave and suspended-sediment data from Liberty Island and Little Holland Tract, Sacramento-San Joaquin Delta, California (ver. 2.0, September 2019)
Data were collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center to investigate the influence of wind waves on sediment dynamics in two flooded agricultural tracts in the northern Sacramento-San Joaquin Delta: Little Holland Tract and Liberty Island. This effort is part of a large interdisciplinary study led by the USGS California Water Science Center...
Hydrodynamic and sediment transport data from San Pablo Bay (northern San Francisco Bay), 2011-2012
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected data to investigate sediment dynamics in the shallows of San Pablo Bay in two deployments: February to March 2011 (ITX11) and May to June 2012 (ITX12). This data release includes time-series data and grain-size distributions from sediment grabs collected during the deployments. During each deployment, time...
Hydrodynamic and sediment transport data from San Pablo Bay and China Camp marsh (northern San Francisco Bay), 2013-2016
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected data to investigate sediment dynamics in the shallows of San Pablo Bay and sediment exchange between bay shallows and the tidal salt marsh in China Camp State Park in a series of deployments between December 2013 and June 2016. This data release includes two related groups of data sets. The first group...
Filter Total Items: 46
Seasonal variation in sediment delivery across the bay-marsh interface of an estuarine salt marsh
Sediment transport across bay–marsh interfaces depends on wave energy, vegetation, and marsh-edge morphology, and varies over a range of timescales. We investigated these dynamics in a tidal salt marsh with a gently-sloped, vegetated edge adjacent to northern San Francisco Bay. Spartina foliosa (cordgrass) inhabits the lower marsh and Salicornia pacifica (pickleweed) predominates on the...
Authors
Jessica R. Lacy, Madeline R. Foster-Martinez, Rachel (Contractor) Allen, Matthew C. Ferner, John C. Callaway
Seasonal, spring-neap, and tidal variation in cohesive sediment transport parameters in estuarine shallows
Numerical models for predicting sediment concentrations and transport rely on parameters such as settling velocity and bed erodibility that describe sediment characteristics, yet these parameters are rarely probed directly. We investigated temporal and spatial variation in sediment parameters in the shallows of San Pablo Bay, CA. Flow, turbulence, and suspended sediment data were...
Authors
Rachel (Contractor) Allen, Jessica R. Lacy, Mark T. Stacey, Evan A Variano
Measuring settling velocity in a strongly tidal estuary
Predicting sediment transport in estuarine systems requires understanding sediment settling velocity, its range of fluctuations, and the shortcomings of the tools to measure it. Previous studies have used Laser In-Situ Scattering and Transmissometry (LISST) instruments to measure particle size and Acoustic Doppler Velocimeters (ADV) to return estimates of settling velocity. We deployed...
Authors
Rachel (Contractor) Allen, Jessica R. Lacy, Evan A Variano
Bed shear stress estimation under wave conditions using near-bottom measurements: Comparison of methods
Understanding the influence of waves on bed shear stress is critical for predicting morphodynamical behaviours in coastal areas. Near-bed flow was measured on the middle and lower intertidal mudflats along the Jiangsu coast, China, using a three-dimensional acoustic velocimeter that collected a 3.5-cm vertical profile at 1mm resolution and sample rate of 25 Hz. On the lower and middle...
Authors
Qian Zhang, Zheng Gong, Changkuan Zhang, Jessica R. Lacy, Bruce Jaffe, Beibei Xu
The influence of neap-spring tidal variation and wave energy on sediment flux in salt marsh tidal creeks
Sediment flux in marsh tidal creeks is commonly used to gage sediment supply to marshes. We conducted a field investigation of temporal variability in sediment flux in tidal creeks in the accreting tidal marsh at China Camp State Park adjacent to northern San Francisco Bay. Suspended-sediment concentration (SSC), velocity, and depth were measured near the mouths of two tidal creeks...
Authors
Jessica R. Lacy, Matthew C. Ferner, John C. Callaway
Three-dimensional modeling of fine sediment transport by waves and currents in a shallow estuary
A suspended sediment transport model is implemented in the unstructured‐grid SUNTANS model and applied to study fine‐grained sediment transport in South San Francisco Bay. The model enables calculation of suspension of bottom sediment based on combined forcing of tidal currents and wind waves. We show that accurate results can be obtained by employing two‐size classes which are...
Authors
Yi-Ju Chou, Kurt S. Nelson, Rusty C. Holleman, Oliver B. Fringer, Mark T. Stacey, Jessica R. Lacy, Stephen G. Monismith, Jeffrey R. Koseff
Wave attenuation across a tidal marsh in San Francisco Bay
Wave attenuation is a central process in the mechanics of a healthy salt marsh. Understanding how wave attenuation varies with vegetation and hydrodynamic conditions informs models of other marsh processes that are a function of wave energy (e.g. sediment transport) and allows for the incorporation of marshes into coastal protection plans. Here, we examine the evolution of wave height...
Authors
Madeline R. Foster-Martinez, Jessica R. Lacy, Matthew C. Ferner, Evan A Variano
Bathymetric survey and digital elevation model of Little Holland Tract, Sacramento-San Joaquin Delta, California
The U.S. Geological Survey conducted a bathymetric survey in Little Holland Tract, a flooded agricultural tract, in the northern Sacramento-San Joaquin Delta (the “Delta”) during the summer of 2015. The new bathymetric data were combined with existing data to generate a digital elevation model (DEM) at 1-meter resolution. Little Holland Tract (LHT) was historically diked off for...
Authors
Alexander G. Snyder, Jessica R. Lacy, Andrew W. Stevens, Emily Carlson
Wave attenuation in the shallows of San Francisco Bay
Waves propagating over broad, gently-sloped shallows decrease in height due to frictional dissipation at the bed. We quantified wave-height evolution across 7 km of mudflat in San Pablo Bay (northern San Francisco Bay), an environment where tidal mixing prevents the formation of fluid mud. Wave height was measured along a cross shore transect (elevation range−2mto+0.45mMLLW) in winter...
Authors
Jessica R. Lacy, Lissa J. MacVean
Mechanisms of sediment flux between shallows and marshes
We conducted a field study to investigate temporal variation and forcing mechanisms of sediment flux between a salt marsh and adjacent shallows in northern San Francisco Bay. Suspended-sediment concentration (SSC), tidal currents, and wave properties were measured over the marsh, in marsh creeks, and in bay shallows. Cumulative sediment flux in the marsh creeks was bayward during the...
Authors
Jessica R. Lacy, Lisa M. Schile, John C. Callaway, Matthew C. Ferner
Model-based interpretation of sediment concentration and vertical flux measurements in a shallow estuarine environment
A one-dimensional numerical model describing tidally varying vertical mixing and settling was used to interpret sediment concentrations and vertical fluxes observed in the shoals of South San Francisco Bay by two acoustic Doppler velocimeters (ADVs) at elevations of 0.36 m and 0.72 m above bed. Measured sediment concentrations changed by up to 100 g m−3 over the semidiurnal tidal cycle...
Authors
Andreas Brand, Jessica R. Lacy, Steve Gladding, Rusty C. Holleman, Mark T. Stacey
Lateral baroclinic forcing enhances sediment transport from shallows to channel in an estuary
We investigate the dynamics governing exchange of sediment between estuarine shallows and the channel based on field measurements at eight stations spanning the interface between the channel and the extensive eastern shoals of South San Francisco Bay. The study site is characterized by longitudinally homogeneous bathymetry and a straight channel, with friction more important than the...
Authors
Jessica R. Lacy, Steve Gladding, Andreas Brand, Audric Collignon, Mark T. Stacey
Science and Products
Filter Total Items: 15
Wind-wave and suspended-sediment data from Liberty Island and Little Holland Tract, Sacramento-San Joaquin Delta, California (ver. 2.0, September 2019)
Data were collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center to investigate the influence of wind waves on sediment dynamics in two flooded agricultural tracts in the northern Sacramento-San Joaquin Delta: Little Holland Tract and Liberty Island. This effort is part of a large interdisciplinary study led by the USGS California Water Science Center...
Hydrodynamic and sediment transport data from San Pablo Bay (northern San Francisco Bay), 2011-2012
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected data to investigate sediment dynamics in the shallows of San Pablo Bay in two deployments: February to March 2011 (ITX11) and May to June 2012 (ITX12). This data release includes time-series data and grain-size distributions from sediment grabs collected during the deployments. During each deployment, time...
Hydrodynamic and sediment transport data from San Pablo Bay and China Camp marsh (northern San Francisco Bay), 2013-2016
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected data to investigate sediment dynamics in the shallows of San Pablo Bay and sediment exchange between bay shallows and the tidal salt marsh in China Camp State Park in a series of deployments between December 2013 and June 2016. This data release includes two related groups of data sets. The first group...
Filter Total Items: 46
Seasonal variation in sediment delivery across the bay-marsh interface of an estuarine salt marsh
Sediment transport across bay–marsh interfaces depends on wave energy, vegetation, and marsh-edge morphology, and varies over a range of timescales. We investigated these dynamics in a tidal salt marsh with a gently-sloped, vegetated edge adjacent to northern San Francisco Bay. Spartina foliosa (cordgrass) inhabits the lower marsh and Salicornia pacifica (pickleweed) predominates on the...
Authors
Jessica R. Lacy, Madeline R. Foster-Martinez, Rachel (Contractor) Allen, Matthew C. Ferner, John C. Callaway
Seasonal, spring-neap, and tidal variation in cohesive sediment transport parameters in estuarine shallows
Numerical models for predicting sediment concentrations and transport rely on parameters such as settling velocity and bed erodibility that describe sediment characteristics, yet these parameters are rarely probed directly. We investigated temporal and spatial variation in sediment parameters in the shallows of San Pablo Bay, CA. Flow, turbulence, and suspended sediment data were...
Authors
Rachel (Contractor) Allen, Jessica R. Lacy, Mark T. Stacey, Evan A Variano
Measuring settling velocity in a strongly tidal estuary
Predicting sediment transport in estuarine systems requires understanding sediment settling velocity, its range of fluctuations, and the shortcomings of the tools to measure it. Previous studies have used Laser In-Situ Scattering and Transmissometry (LISST) instruments to measure particle size and Acoustic Doppler Velocimeters (ADV) to return estimates of settling velocity. We deployed...
Authors
Rachel (Contractor) Allen, Jessica R. Lacy, Evan A Variano
Bed shear stress estimation under wave conditions using near-bottom measurements: Comparison of methods
Understanding the influence of waves on bed shear stress is critical for predicting morphodynamical behaviours in coastal areas. Near-bed flow was measured on the middle and lower intertidal mudflats along the Jiangsu coast, China, using a three-dimensional acoustic velocimeter that collected a 3.5-cm vertical profile at 1mm resolution and sample rate of 25 Hz. On the lower and middle...
Authors
Qian Zhang, Zheng Gong, Changkuan Zhang, Jessica R. Lacy, Bruce Jaffe, Beibei Xu
The influence of neap-spring tidal variation and wave energy on sediment flux in salt marsh tidal creeks
Sediment flux in marsh tidal creeks is commonly used to gage sediment supply to marshes. We conducted a field investigation of temporal variability in sediment flux in tidal creeks in the accreting tidal marsh at China Camp State Park adjacent to northern San Francisco Bay. Suspended-sediment concentration (SSC), velocity, and depth were measured near the mouths of two tidal creeks...
Authors
Jessica R. Lacy, Matthew C. Ferner, John C. Callaway
Three-dimensional modeling of fine sediment transport by waves and currents in a shallow estuary
A suspended sediment transport model is implemented in the unstructured‐grid SUNTANS model and applied to study fine‐grained sediment transport in South San Francisco Bay. The model enables calculation of suspension of bottom sediment based on combined forcing of tidal currents and wind waves. We show that accurate results can be obtained by employing two‐size classes which are...
Authors
Yi-Ju Chou, Kurt S. Nelson, Rusty C. Holleman, Oliver B. Fringer, Mark T. Stacey, Jessica R. Lacy, Stephen G. Monismith, Jeffrey R. Koseff
Wave attenuation across a tidal marsh in San Francisco Bay
Wave attenuation is a central process in the mechanics of a healthy salt marsh. Understanding how wave attenuation varies with vegetation and hydrodynamic conditions informs models of other marsh processes that are a function of wave energy (e.g. sediment transport) and allows for the incorporation of marshes into coastal protection plans. Here, we examine the evolution of wave height...
Authors
Madeline R. Foster-Martinez, Jessica R. Lacy, Matthew C. Ferner, Evan A Variano
Bathymetric survey and digital elevation model of Little Holland Tract, Sacramento-San Joaquin Delta, California
The U.S. Geological Survey conducted a bathymetric survey in Little Holland Tract, a flooded agricultural tract, in the northern Sacramento-San Joaquin Delta (the “Delta”) during the summer of 2015. The new bathymetric data were combined with existing data to generate a digital elevation model (DEM) at 1-meter resolution. Little Holland Tract (LHT) was historically diked off for...
Authors
Alexander G. Snyder, Jessica R. Lacy, Andrew W. Stevens, Emily Carlson
Wave attenuation in the shallows of San Francisco Bay
Waves propagating over broad, gently-sloped shallows decrease in height due to frictional dissipation at the bed. We quantified wave-height evolution across 7 km of mudflat in San Pablo Bay (northern San Francisco Bay), an environment where tidal mixing prevents the formation of fluid mud. Wave height was measured along a cross shore transect (elevation range−2mto+0.45mMLLW) in winter...
Authors
Jessica R. Lacy, Lissa J. MacVean
Mechanisms of sediment flux between shallows and marshes
We conducted a field study to investigate temporal variation and forcing mechanisms of sediment flux between a salt marsh and adjacent shallows in northern San Francisco Bay. Suspended-sediment concentration (SSC), tidal currents, and wave properties were measured over the marsh, in marsh creeks, and in bay shallows. Cumulative sediment flux in the marsh creeks was bayward during the...
Authors
Jessica R. Lacy, Lisa M. Schile, John C. Callaway, Matthew C. Ferner
Model-based interpretation of sediment concentration and vertical flux measurements in a shallow estuarine environment
A one-dimensional numerical model describing tidally varying vertical mixing and settling was used to interpret sediment concentrations and vertical fluxes observed in the shoals of South San Francisco Bay by two acoustic Doppler velocimeters (ADVs) at elevations of 0.36 m and 0.72 m above bed. Measured sediment concentrations changed by up to 100 g m−3 over the semidiurnal tidal cycle...
Authors
Andreas Brand, Jessica R. Lacy, Steve Gladding, Rusty C. Holleman, Mark T. Stacey
Lateral baroclinic forcing enhances sediment transport from shallows to channel in an estuary
We investigate the dynamics governing exchange of sediment between estuarine shallows and the channel based on field measurements at eight stations spanning the interface between the channel and the extensive eastern shoals of South San Francisco Bay. The study site is characterized by longitudinally homogeneous bathymetry and a straight channel, with friction more important than the...
Authors
Jessica R. Lacy, Steve Gladding, Andreas Brand, Audric Collignon, Mark T. Stacey