Relationships among Fine Sediment Settling and Suspension, Bed Erodibility, and Particle Type in the York River Estuary, Virginia

In order to understand the processes controlling the temporal variability in settling velocity (Ws) and bed erodibility (ε), in the middle reaches of the York River estuary, VA, the relationships between the hydrodynamics and particle types were investigated with a near-­‐bed Acoustic Doppler Velocimeter (ADV) and the York River 3-­‐D Hydrodynamic Cohesive Bed Model. ADV observations of the flow characteristics that occurred over a strong temporal transition period indicated that Ws and ε were characterized by two distinct regimes with contrasting sediment and water column characteristics: (i) a physically-­‐dominated regime (Regime 1) which was a period dominated by flocculated muds (flocs), and (ii) a biologically-­‐influenced regime (Regime 2) which was a period dominated by biologically formed pellets mixed with flocs. During Regime 1, Ws averaged about 0.5 mm/s, and ε averaged about 3 kg/m2/Pa. In contrast, during Regime 2 average Ws increased to 1.5 mm/s, and average ε dropped to 1 kg/m2/Pa. The change between these two regimes and the transition in Ws and ε were linked with the arrival and departure of a seasonal density front. Comparison between ADV observations and the results from the York River 3-­‐D Hydrodynamic Cohesive Bed Model suggested that the current model version was not conducive to examining the temporal variability in settling velocity associated with the transition of the distinct sediment regimes. The existing model version estimated realistic values for current speed and concentration and resolved the daily variation associated with in current speed, bed stress, concentration, and settling velocity. However, model estimates of bed stress, current speed, settling velocity, and erodibility did not suggest the presence of two distinct sediment regimes. The model did a poor job of predicting peak bed stresses and settling velocities. Both were over estimated by a factor of 2 throughout most of the study period. Possible modifications to create a version that is able to simulate the bed stresses and sediment properties (i.e. erodibility and settling velocity) during each regime with more accuracy are: (1) define finer sediment classes in the model that are more representative of the water column and not just the seabed, (2) use a consolidation time scale of 5 days rather than 24 hours to allow more sediment to be suspended at lower bed stresses, (3) further reduce hydraulic roughness, and (4) turn on sediment induced stratification

Suspended Particulate Matter Longitudinal Survey – Currituck Sound, NC; Oct 13-15, 2015, Cruise: CS151013-15, CHSD Stations: S5566-5587

Dataset consists of water column and bottom burst data, PICS, and light attenuation data collected as part of a 21 station longitudinal survey of the Currituck Sound, NC along a ~60 km transect northward from the Wright Memorial Bridge

Identification of suspended resilient pellets in particles tracked by a Particle Image Camera System (PICS) in a muddy estuary

The Particle Imaging Camera System (PICS) was designed to allow for the measurement of the settling velocity of individual particles in situ by using the smaller particles (\u3c density \u3c 1800kg/m3 ). This classification system, while adequate for suspended dredge plumes, needs to be revisited when the PICS is used in a muddy estuary, such as the York River Estuary, Virginia. Figure 1B shows the settling velocities of particles tracked within a video captured 2.5m from the surface in the Clay Bank region of the York River, plotted against their equivalent spherical diameters. While most of the particles are classified as flocs, as indicated by the blue dots in Figure 1C and the peak in the relative number of particles in Figure 1E, there is still a large number of particles classified as “bed aggregates” (red dots). This number of higher density particles may be unexpected, as this video was captured 4.25m over a “muddy bed” in a natural system with a flood current of 40cm/s. However, biologically compacted mud in the form of resilient pellets (see Figure 2) may be the answer. Bed sediments from five sediment cruises during this study period (Aug 2012 – Nov 2014) were found to be comprised of 86-96% mud (Figure 3A). However, 9-14% of the mud was packaged as resilient pellets (Figure 3B). Sediment captured 38cm above the bed by traps deployed on tripods were found to have 92-98% mud, with 4-14% of the mud packaged as resilient pellets (Figures 3A and B). Pellets isolated from the Apr to Jul 2014 trap were sampled with the PICS to determine the distribution of settling velocities (Ws), particle densities, and the ratio of the long and short axis of the particles. This will be used to identify the pellets in PICS videos captured during the five 6h anchor stations (black lines in Figure 3) where three depths were sampled each hour

The importance of organic content to fractal floc properties in estuarine surface waters, insights from video, LISST, and pump sampling: Supporting data

The linked folders and associated data files contain the observations utilized in Fall, K.A., Friedrichs, C.T., Massey, G.M., Bowers, D.G., and Smith, S.J. (2021). The importance of organic content to fractal floc properties in estuarine surface waters: Insights from video, LISST, and pump sampling. JGR Oceans. The file “Description of Data Files.pdf” outlines the content of the ten data folders, each of which is associated with a data set collected on an individual one-day cruise in the York River estuary

Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

Water clarity is a subjective term and can be measured multiple ways. Different metrics such as light attenuation and Secchi depth vary in effectiveness depending on the research or management application. In this essay, we argue that different questions merit different water clarity metrics. In coastal and inland waters, empirical relationships to estimate light attenuation can yield clarity estimates that either under- or overestimate the underwater light climate for restoration goals, such as potential habitat available for submerged aquatic vegetation. Best practices in reporting water clarity measurements include regionally specific, temporally representative calibrations and communicating the metric that was actually measured. An intentional choice of the water clarity metric best suited to the research or management question yields the most useful results

Cruise: YR130612, Stations: S5127- S5138, York River Estuary and Pamunkey River, Virginia, MUDBED Longitudinal Profiler Station Survey bracketing a Flood Tide.

Dataset consists of profile and water column burst Data collected as part of a longitudinal profiler station survey at approximately 20 km, 25 km, 35 km, 45 km, 56 km and 62 km upriver from the mouth of the York River Estuary

Collaborative Research: The Role of Wind in Estuarine Dynamics, Upper Chesapeake Bay, VIMS Instruments deployed in collaboration with UMCES and WHOI; March-May, 2012 deployment.

While the project is a collaborative effort involving several researchers from the Virginia Institute of Marine Science (VIMS), the University of Maryland Center for Environmental Science (UMCES) and the Woods Hole Oceanographic Institution (WHOI), the Data archive here is primarily from VIMS owned instrumentation deployed as part of the project. A series of instruments were deployed in three transects in Upper Chesapeake Bay, South of the Choptank River from March to May 2012. This Dataset was collected with autonomously deployed Acoustic Doppler Current Profilers (ADCP), Acoustic Doppler Velicometers (ADV), and Conductivity and Temperature Sensors (CT)

Impacts of Muddy Bed Aggregates on Sediment Transport and Management in the tidal James River, VA

Aggregation state significantly influences the size, density and transport characteristics of fine sediment. Understanding sediment transport and deposition processes in the nation’s navigable waterways is a primary mission for the US Army Corps of Engineers (USACE), particularly when it comes to infilling of navigation channels. In this study, a newly developed camera system was used to evaluate the aggregation state of eroded sediment from cores collected in the tidal James River, VA. Results showed that bed sediments were composed mostly of mud, but that erosion predominately occurred in the form of aggregates with median sizes 50-270x larger than the disaggregated sediment. Aggregate size weakly correlated to shear stress at levelsPa, as well as sand content and bed density. A numerical simulation demonstrated that mud aggregates were predicted to transport in incipient suspension or bedload, while disaggregated fines were predominately maintained in full suspension. This difference in transport mode has significant implication for channel infilling and sediment transport within the system

A Data Repository for Clarifying water clarity: a call to use metrics best suited to corresponding research and management goals in aquatic ecosystems (York River estuary case study dataset)

This data repository is a permanent archive of the results presented in the associated publication (Turner et al. 2020, Limnology & Oceanography Letters, doi.xxxx). The objective of this study was to illustrate a water clarity phenomenon in the lower York River Estuary of the Chesapeake Bay. The data include light attenuation, Secchi depth, turbidity, and salinity from the lower York River Estuary in western Chesapeake Bay, Virginia, USA from the years 2014-201

Sediment Survey: YR120120, Station S4989-S4991, Clay Bank, York River Virginia

This dataset consists of sediment properties including grain size distribution, percent moisture, percent organic matter, sediment bed erodibility, as well as (in most cases) x-ray images of the sediment structure. Most samples were taken in support of an Acoustic Doppler Velocimeter (ADV) tripod deployed in nearby location