Data and Model Archive for Simulations of Seawater Restoration on Diked Salt Marshes

This dataset and model archive provides geochemical modeling input and selected output data used in simulations of seawater restoration on historically diked salt marshes. Biogeochemical changes resulting from seawater reintroduction were simulated using the computer program PHREEQC (Parkhurst and Appelo, 2013) to help support efforts to restore tidal flow and associated estuarine habitat to diked marshes, including the Herring River estuary in Wellfleet, Massachusetts, on Cape Cod. First, one-dimensional reactive transport models were developed and calibrated using data from Portnoy and Giblin (1997) microcosm experiments of sediment cores to better understand the associated timing and sequence of biogeochemical reactions and their implications to aquatic health. These cores included diked, flooded marsh sediments and subaerially exposed, diked, drained sediments representative of the Herring River diked marsh (Portnoy and Giblin, 1997). Solute concentrations measured in the microcosm experiment data were used to estimate sedimentary organic matter decay rates by matching the timing and magnitude of simulated dissolved ferrous iron and sulfide concentrations. Then, "basecase" models were used to simulate a single flow velocity to better understand biogeochemical conditions over longer time periods and with varying ferric iron source minerals.

This data release includes the metadata and the data and model archive folder "HerringR_PHRQC.zip", which contains the following files:

1. readme.txt — documents the work that was done, the structure of the model data release, the model files, and instructions on how to run the PHREEQC simulations.
2. HerringR_PHRQC_input.xlsx — a workbook of 14 PHREEQC model inputs as separate worksheets that can be copied and pasted into PHREEQCi input (pqi) files.
3. HerringR_PHRQC_seloutput.xlsx — a workbook of selected output for each model in separate worksheets.
4. data_dictionary_seloutput.csv — specific to "HerringR_PHRQC_seloutput.xlsx" providing the definitions for each column in selected output worksheets.
5. phreeqci.exe — executable file to run PHREEQC Interactive, the graphical users interface to PHREEQC, as described in the readme.txt file.
6. phreeqc.dat — the geochemical database used in simulations for this study.

References
Parkhurst, D.L., and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC version 3: a computer program for speciation, batch-reaction, one-dimensional transport, and inverse     geochemical calculations: U. S. Geological Survey Techniques and Methods 6-A43 6-        A43, 519 p., http://pubs.er.usgs.gov/publication/tm6A43.
Portnoy, J.W., and Giblin, A.E., 1997, Biogeochemical effects of seawater restoration to diked salt marshes: Ecological applications, v. 7, no. 3, p. 1054-1063, https://doi.org/10.1890/1051-   0761(1997)007[1054:BEOSRT]2.0.CO;2.