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 continued to maintain three instruments on two fence-post mounted platforms and one fiberglass grated bottom landing platform. All platforms are located 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. Water samples were collected in February, April, and December of 2025 from the footbridge with a handheld sampler. 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.
In May of 2025, the IQ was removed due to technical difficulties and was not re-deployed. It was determined that enough velocity and flow data was collected; however, the IQ may be re-deployed at the same location in the future.
The Exo and RBR 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. We will continue to conduct site visits every ~3 months to switch out the instruments and collect elevation data. 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 from the footbridge with a handheld sampler multiple times a year.
AIM mapped the area with UAS twice, in March and in July. The March data collect included lidar, rgb photos, and GPS check shots. The July data collect included lidar, rgb, multispectral, thermal imagery, and gps check shots. From the UAS data, multiple orthomosaics and elevation models were made.
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. 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.
Entries for this field activity are based on entries from Field Activity 2023-025-FA.
Entries for this field activity are based on entries from Field Activity 2024-004-FA.
Bales and Marsjanik checking on CED instruments/moorings under bridge at Marsh Island for any ice interference. Will assess if next instrument turnaround should happen in the next couple weeks or pull instruments for remainder of winter.
2025-02-26
2025-02-26
Bales and De Meo doing a turn-around of Exo, Dwave, and IQ.
2025-03-11
2025-03-11
J. Over and A. Milo will be performing a lidar UAS survey at low tide.
2025-04-29
2025-04-29
Bales and De Meo collecting water samples.
2025-05-27
2025-05-27
Bales and De Meo turning around instruments.
2025-07-23
2025-07-23
AIMG group and Brita are going out to collect UAS Skydio RGB, Wingtra Lidar, M600 Lidar and Multispectral imagery for a mid-summer peak vegetation dataset.
2025-08-20
2025-08-20
Bo and Neil switching out Exo and Dwave; removing battery platform and fence post mount for IQ
2025-12-04
2025-12-04
Bo and Olivia collecting water samples and switching out instruments at Marsh Island
