Monitor the hydrodynamics and sediment supply to a newly engineered system. Buzzards Bay Coalition and their partners have just completed Phase I of this project to create an engineered salt marsh on a former fill area. Sediment supply is a key factor in salt marsh sustainability with rising sea-level, this site provides a unique opportunity to study the establishment of the engineered system under the natural forcing of the tides and water flow.
Location
Marsh Island site New Bedford Harbor, Acushnet River, Fairhaven, MA..
Summary
We deployed three instruments on two fence-post mounted platforms and one bed-mounted platform. All platforms are under the footbridge in the center of the channel on the seabed. The first fence-mounted platform contains a Sontek IQ+, which measures water velocity and flow every 15 minutes. This yields a volumetric water flux over each tide, and any net flux in/out during storms and rainfall events. Adjacent to this, connected with a power cable, is a submersible battery on a bed mounted fiberglass grate, weighted down with ~ 60 lbs.
On the second platform, we have a YSI EXO2, which measures water depth, turbidity, salinity, pH, oxygen, fluorescent dissolved organic material, and chlorophyll every 15 minutes. Along with water samples, we can convert the turbidity signal to suspended sediment, and with the flow data, compute sediment fluxes in/out of the system. This platform also has an RBR Dwave, which measures wave height and period.
We will conduct site visits every ~3 months to switch out the instruments, download data, and add battery power. Water samples were collected in December of 2023.
Disturbance at the site will be minimal as the platforms will stay in place and the instruments will be temporarily removed. Water sampling will continue to be conducted multiple times a year from the footbridge with a handheld sampler. These instruments will remain on-site for the duration of the experiment, which ideally will last until the system is completely vegetated and in a quasi-equilibrium.
Info derived
Time-series data of water level, currents, flow/discharge, waves, turbidity, and other water-quality parameters (temperature, salinity, chlorophyll, dissolved oxygen, pH, fDOM, blue-green algae). Supplemental water samples will be collected and analyzed for total suspended-sediment concentration and loss-on-ignition. Grain-size distribution will be determined from sediment samples collected the marsh creek bed. Aerial mapping will provide full elevation coverage and multispectral orthoimage data. Biochem time-series sensor data are groundwater well CTD measurements.
Comments
This will be an ongoing study and would like it to be an event type field activity. Multiple Information specialists due to group overlap.
Installed an exo and dwave on the same fence post mount in the main marsh channel opening to New Bedford Harbor. Installed an IQ on a separate fence post mount in the same marsh channel. Both fence posts are located under the pedestrian bridge that crosses the channel. Instruments were deployed for time-series measurements of water level, currents, flow/discharge, waves, turbidity, and other water-quality parameters (temperature, salinity, chlorophyll, dissolved oxygen, pH, fDOM, blue-green algae).
Collected three sediment samples from the channel bank sand, channel bank peat, and channel bed. Grain-size distribution will be determined from sediment samples collected the marsh creek bed.
Purpose: monitor the hydrodynamics and sediment supply to the marsh system.
Personnel: Neil Ganju, Steve Suttles, Robert Bales, Jenny Cramer, Emily Tacke, Jin-Si Over, Meagan Eagle
2023-10-26
2023-10-26
S. Brosnahan, J. Over, and J. Cramer visited site with UAS equipment and flew the M600 with the Altum PT (multispectral data) and YellowScan Mapper+ (lidar and RGB camera) attached. AeroPoints were deployed as ground control.
2023-12-18
2023-12-18
Water sampling during high winds to catch an event resuspending sediment. 21 water samples collected on same sampling interval as optical turbidity measurements from the deployed exo. Water samples were collected 30 cm above bed from the pedestrian bridge crossing the main marsh channel the exo is deployed in.
Purpose: NTU to SSC (mg/l) calibration for the optical turbidity measurements from the deployed exo.
Personnel: Neil Ganju, Robert Bales
Multispectral aerial imagery collected from UAS (DJI Matrice 600) equipped with the Altum-PT. Image locations are provided in a CSV. Bands include (RGB, NIR, Red-Edge, Thermal)
Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from multispectral and true-color aerial imagery data, collected during UAS operations at Marsh Island, New Bedford, MA on October 26th, 2023. Contains CSV files of image and Aero Point locations, orthophotos, digital surface model, digital terrain model and lidar point cloud. Individual images are available from the Imagery Data System.
Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from multispectral and true-color aerial imagery data, collected during UAS operations at Marsh Island, New Bedford, MA on October 26th, 2023. Contains CSV files of image and Aero Point locations, orthophotos, digital surface model, digital terrain model and lidar point cloud. Individual images are available from the Imagery Data System.
Lidar point cloud, elevation models, GPS data, and imagery and orthomosaics from multispectral and true-color aerial imagery data, collected during UAS operations at Marsh Island, New Bedford, MA on October 26th, 2023. Contains CSV files of image and Aero Point locations, orthophotos, digital surface model, digital terrain model and lidar point cloud. Individual images are available from the Imagery Data System.
