Continuous Monitoring Data From Herring River Wetlands, Cape Cod, Massachusetts, 2015 to January 2020

PVC wells were installed by USGS at four of the five sites; the Dry Forest well was previously installed by collaborators at the National Park Service (NPS). USGS wells consisted of two pre-manufactured sections of 1 inch (2.54 cm) diameter well casing that were threaded together: a length of slotted screened casing (2.5 feet, ~0.762 meters; slot size 0.010 inch; ~ 0.3 mm) and a solid well casing that stuck above the sediment surface. USGS wells were installed by pushing the well section into the sediment by hand or lightly tapping the top of the well with a mallet. The tip of the slotted screened well section was pushed about 1 meter below the land surface for deep wells and about 0.3 meters below land surface for shallow wells; the threaded portion (connecting the slotted length with the solid length) was below the sediment surface. Enough well casing remained above the sediment surface to ensure the groundwater well was not over-topped with surface water (0.3 meter - 1 meter). A vent hole was drilled near the top of the solid well casing. An eye-bolt was drilled into the inward facing edge of the threaded well cap; water level loggers were hung by aircraft cable threaded through the eye-bolt and through the logger cap and secured on both ends using crimped stainless-steel oval sleeves. Exact well heights and sensor deployment lengths are summarized in a separate entity and attribute section (HR_WellSensorDeploymentHeights_2015_2019.txt).
The NPS Dry Forest well was a 1.5 inch diameter PVC well (0.010 inch slotted screen) loosely capped with a PVC cap socket. The water level logger hung using the same aircraft cable used in the other wells; however it was not attached to the cap, it hung from a bolt between holes drilled approximately 4 cm from the top of the well casing.
We categorize the Typha site well installed in 2015 as "deep". In 2016, we attempted to collect water level data from a shallower well (0.3 meters below land surface) at the Typha site in order to log salinity closer to the root zone. However, this well suffered from low water level during a drought year in addition to a series of data logger problems. Therefore, water level data is unavailable from the Typha site for much of 2016 until we moved the logger back to the deeper well.
In 2017, we installed the Wet Shrub site well, the Phragmites “deep” well and the Phragmites “shallow” well. To prevent possible disturbance from other on site research activities, the Phargmites wells were moved, in 2019, slightly further away from the walking path. The process date represents the latest process date.

Additional sensors were co-deployed at the same sites as the groundwater level sensors including: dual channel (soil and air) temperature loggers, a barometer, and a photosynthetically active radiation (PAR) sensor. In 2017, the PAR sensor was moved from the Typha site to the Phragmites site and additional meteorological sensors were deployed on the same mast with the PAR. The PAR sensor and anemometer were deployed on a mast above the height of the nearest vegetation in a location that would not be shaded or impacted by vegetation or other structures (at least 3 meters above the land surface). The other meteorological sensors (rain gauge, air temperature/relative humidity) were deployed on the same mast about 2 meters above the land surface. The barometer was deployed in air (approximately 1.5 meters above the land surface) near to the PAR sensor. Note that, within the Phragmites site, the meteorological station was deployed on an exposed knoll with less vegetation density and less standing water than is otherwise characteristic of the site. This was done to to capture weather data above the height of the dense Phragmites canopy. The dual channel soil/air temperature logger were deployed with the water level wells within the Phgramites vegetation.
Soil temperature sensors were attached to a wooden stick and pushed by hand so that the bottom of the temperature sensor was 10 cm below the land surface. The air temperature sensor was attached near to the top of the groundwater well (approximately 1 meter above the land surface; for exact well heights, see included text file, HR_WellSensorDeploymentHeights_2015_2019.txt). Note that draft shields were not consistently used for air temperature sensors until 2017. The Wet Forest air temperature logger was attached to a well; however water level data was not collected at this site. Soil/air temperature data is not available for the Wet Shrub site.
Data was logged in 15 minute intervals for all parameters. Specific deployments may have been started immediately (not on a timed interval). Additionally, the Onset HOBO Micro Station, used to log data from the meteorological sensors, has a one-time 2 second delay upon starting up a new sequence that cannot be avoided. Deployments took place between 2016 and January 2020, with the process date representing the latest process date.

Well data loggers were initially deployed at two sites in September 2015. In subsequent years, additional sites, wells, and sensors were added to the study. In some years, sensors were removed from the field over winter and redeployed in spring. Data loggers were periodically downloaded in the field using instrument manufacturers' software (HOBOPro, WinSitu); data were inspected for general accuracy. Further data processing and calculation steps are described in the next process steps. Note that temperature loggers were not deployed at all sites for the entire study period. Dates of site visits are listed as follows, Typha: 9/29/2015, 10/7/2015, 11/13/2015, 1/4/2016, 5/16/2016, 6/17/2016, 7/6/2016, 7/14/2016, 7/22/2016, 8/17/2016, 8/30/2016, 9/16/2016, 10/6/2016, 10/28/2016, 11/10/2016, 4/27/2017, 5/19/2017, 6/16/2017, 6/22/2017, 6/28/2017, 7/11/2017, 7/19/2017, 8/28/2017, 10/3/2017, 1/3/2018, 4/24/2018, 5/24/2018, 7/11/2018, 9/21/2018, 12/19/2018, 4/29/2019, 5/14/2019, 7/17/2019, 9/26/2019, 1/8/2020. Dry Forest: 9/29/2015, 10/7/2015, 11/13/2015, 1/4/2016, 6/17/2016, 7/14/2016, 8/30/2016, 10/28/2016, 11/10/2016, 4/27/2017, 6/16/2017, 7/11/2017, 10/3/2017, 1/3/2018, 4/24/2018, 5/24/2018, 7/11/2018, 9/21/2018, 12/19/2018, 4/29/2019, 5/14/2019, 7/17/2019, 9/26/2019, 1/8/2020. Wet Forest: 7/11/2017, 10/3/17, 1/3/18, 4/24/18. Wet Shrub: 6/9/2017, 6/22/2017, 7/11/2017, 7/19/2017, 8/22/17, 9/27/17, 10/3/17, 1/3/2018, 5/24/2018, 7/11/2018, 9/21/2018, 12/19/2018, 4/29/2019, 5/14/2019, 7/17/2019, 9/26/2019, 1/8/2020. Phragmites: 6/9/2017, 6/16/2017, 6/28/2017, 7/11/2017, 7/19/2017, 8/22/17, 9/27/2017, 10/3/2017, 10/27/17, 1/3/2018, 5/24/2018, 7/11/2018, 9/21/2018, 12/19/2018, 4/29/2019, 5/14/2019, 7/17/2019, 9/26/2019, 1/8/2020.
The process date represents the latest process date.

Pressure data from non-vented water level sensors were barometrically corrected in manufacturers’ software (HOBOPro or WinSitu BaroMerge); corrected pressure was converted to sensor depth assuming a brackish water density (HOBOPro: 1.010 grams per cubic centimeter; WinSitu: 1.012 grams per cubic centimeter). Barometric pressure and density corrections were processed throughout the deployment period and checked while finalizing the data report. Raw pressure and barometric pressure are reported in this data release.
Data from all continuous monitoring sensors were exported from manufacturers' software as a .csv file and compiled using MATLAB. Water elevation calculations were performed in MATLAB as described in the following process steps. Data resulting from erroneous measurements (malfunctioning sensors or insufficient water within a well) were excluded from the final dataset. Data were processed throughout the deployment period and checked while finalizing the data report; the process date represents the latest date of data processing.

Field measured deployment heights for specific time periods are summarized in a txt file (tab-delimited, filename: HR_WellSensorDeploymentHeight_2015_2019.txt) included with this data release. These deployment heights were used to convert sensor depth (calculated from pressure in the manufacturer's software; described in previous process step) to water depth below land surface (dbs) and water elevation (WL_NAVD88). Calculations were processed throughout the deployment period in MATLAB. Positive dbs indicates water above the land surface; negative dbs indicates water below the land surface. The following parameters are used for these two calculations (units for all measurements are in meters): a: depth of sensor as calculated in manufacturer's software (see previous process step for description of measured pressure data and assumptions of density constants) b: land surface elevation (in the NAVD88 datum) at deployment location measured by RTK (land_surface_elevation; positive above (elevation) and negative below the datum) c: deployment well height above land surface measured periodically in the field using a meter stick (height_above_land_surface; always positive) d: total length of the deployment cable and water level sensor measured in the field using a meter stick (deployment_length; always positive)
Well water elevation is calculated as: WL_NAVD88 = a +b+c-d
Well water depth below land surface is calculated as: dbs = a+c-d
Calculations were processed throughout the deployment period; the process date represents the latest date of data processing.

Added keywords section with USGS persistent identifier as theme keyword.