Assessing Effectiveness of Runnels in New England (Water Elevation Time Series, Field Monitoring, and Geospatial Dataset)

<b>Project Description:</b>In New England, runnels have been adopted and implemented in Rhode Island and Massachusetts with the intent to restore tidal hydrology to the marsh platform, stop the expansion of shallow water pools, and create sufficient growing conditions for high marsh graminoids (e.g., Spartina patens, Distichlis spicata, and Juncus gerardii). Long-term restoration goals of these projects include enhancing salt marsh resiliency to sea level rise and preserving high marsh habitat for specialized fauna such as the saltmarsh sparrow. Monitoring efforts of previous runnel and ditch plug removal projects have generally been tailored to one or several sites and the broader applicability and success rate of the technique has not been evaluated on a regional basis (although see Sullivan et al. 2024).To evaluate the effectiveness of runneling as a restoration tool, comprehensive monitoring of hydrology, vegetation, surface elevation, and the avian community was completed for two growing season over three years at 20 restoration sites in a modified after - control – impact (ACI) experimental design. Runnels were created between 2011 – 2022 across Maine, Massachusetts, and Rhode Island, which allowed for a space for time substitution to draw conclusions of their impact in the short (&lt; 5 years) and medium-term (5 – 10 years). The project asked one fundamental research question pertaining to marsh platform conservation and restoration: How does the hydrology, vegetation community, and avian community respond to drainage enhancement efforts over time.<b>Dataset Description</b>Dataset for the entire project is brokend own into three comprehensive files: (1) Field monitoring data (Excel), (2) Time series of water elevations (Excel), and (3) Geospatial locations of field monitoring (File Geodatabase). <b><i>Field Monitoring Data</i></b>Field monitoring data is the comprehensive dataset for vegetation monitoring (visual cover estimation, species identification, transect - plot monitoring), surface elevations (transect-based elevations with laser level - rod and RTK-GPS), calculated tidal datums and flood metrics, and avian point count surveys. Metadata is provided for background and site history for each salt marsh site (n = 21). Raw data for vegetation monitoring, surface elevation surveys, and avian point counts are included. Vegetation and bird species codes and species names are included in separate sheets. Spring tide adjustments, marsh platform elevations, and other necessary information to calculate tidal datums and flooding metrics for water level recorders are included.<br><b><i>Water Elevation Time Series</i></b>The time series of water elevations used to calculat tidal datums and flood metrics are compiled for each site on a separate sheet in the dataset. Water elevations were recorded with a Hobo pressure transducer (Onset Corporation) deployed for at least 28 days at 10 minute intervals. Water elevations on the date of deployment and collection were removed from the dataset. Pressures were transformed into water elevations using Hoboware Software and atmospheric pressure was compensated with a separate pressure transducer deployed in trees nearby. Water elevations were transformed into a vertical datum (NAVD88 m) with a Real-Time Kinematic GPS (Leica GNSS14 or GNSS16). Spring tide adjustments were made to groundwater level recorders if the difference in maximum water elevation between the local creek and ground water level recorders exceeded +/- 4 cm. All relevant information are provided in this dataset and the field monitoring dataset. <b><i>Geospatial Dataset</i></b>The locations of tidal watersheds ('tidesheds'), monitoring transects, and water level recorders are provided if future studies wish to replicate or continue monitoring at the sites. Relevant metadata and descriptions are included in the attribute tables for all geospatial datasets. <br>Funding for the project was provided by the United States Fish and Wildlife Service (F21AP00933-00). This project is the field monitoring component of <b><i>Evaluation of Drainage Enhancement for Vegetation Recovery in New Engalnd Salt Marshes Using Public Domain, High-Resolution Aerial Imagery</i></b> (doi: 10.2112/JCOASTRES-D-24-00011.1). The accompanying geospatial dataset for the remote sensing component of the project can be found on FigShare at: 10.6084/m9.figshare.25180226.v1. R code for data analysis across the entire project can be found at GitHub in perpetuity: https://github.com/Wetland-Botanist/Runnel-Effectiveness-ACJV-2025.<br>All questions or concerns about the dataset can be directed to Grant McKown, University of New Hampshire, at [e-mail].