Supporting Data for: Spatial and temporal variation in drivers of saltmarsh eco-geomorphic evolution: Field insights from the St. Lawrence Estuary, Canada

This field dataset was collected from the saltmarshes of the Petites-Bergeronnes River, Quebec, Canada (48º14’6.27” N, 69º34’39.97” W). Eight field campaigns were conducted from July-October 2023 and May-August 2024, to support a hydro-eco-geomorphic characterization of the site. The resulting dataset is organized into three folders, containing data related to each: (1) Hydrodynamics, (2) Sediment dynamics, and (3) Vegetation.

HYDRODYNAMICS
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Three types of instruments were deployed for collection of hydrodynamic data. Six pressure sensors (RBR soloD) were deployed throughout the Petites-Bergeronnes River (P1-6) measuring tide characteristics. One acoustic doppler current profiler (ADCP) (Nortek ECO) was deployed for collection of current velocities, at two different locations during the 2023-24 campaigns (C1, C2). Six MSR accelerometers, or "mini buoys" , were deployed at 30 different locations over the various campaigns, measuring acceleration (g) along the sensor's y-axis. This dataset captures transitions from dry to flooded conditions (point measurement).

SEDIMENT DYNAMICS
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Sediment dynamics were investigated along two transects perpendicular to the saltmarsh edge, each with 5 sampling stations. Deposition (D) (sediment mass) was measured on acrylic tiles over periods of appr. 1 month, and siphon samplers were used for measurements of suspended sediment concentration (SSC) in tidal floodwaters.

VEGETATION
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Two types of vegetation surveys were conducted with 0.5 m x 0.5 m quadrats. Random quadrat surveys were performed for species distribution (quadrat percent coverage by species). Repeated (seasonal) quadrat surveys along two marsh edge transects (10 m intervals) consisted of percent coverage and stem length and diameter measurements for dominant species.

GEOSPATIAL DATA
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RTK data for instrument/sampling locations was collected using Emlid Reach GNSS receivers. Root-mean-square error for positioning (easting, northing, elevation) was always < 3 cm. All RTK GPS data was collected in the following coordinate system:
• Horizontal Datum : NAD83 (CSRS)
• Projection : UTM19N
• Vertical Datum : CGVD2013
• Geoid Model : CGG2013