This data set includes dissolved oxygen (DO) and specific conductivity (SpC) data collected in both the surface water and shallow streambed at the Quashnet River, Mashpee, USA from 2014-16. This data was collected to better understand groundwater discharge to the river and associated brook trout habitat. DO was typically near saturation in surface water and some groundwater, but is reduced in streambed zones that may be influenced by buried peat lenses. SpC was used as an indicator of groundwater flowpath dynamics, and lower values were generally associated with higher DO.

This data release contains groundwater flux estimates from twelve locations in wetlands surrounding the Quashnet River in Cape Cod, located near Mashpee and Falmouth, Massachusetts. A VTP (i.e., rod with vertical temperature sensors with known spacings and depths) was also installed at a key groundwater discharge location to estimate 1D groundwater flux through time (Sohn et al., 2024). Vertical discharge flux patterns were estimated over time using the extended Kalman Filter (EKF) recursive estimation approach of McAliley et al. (2022). The EKF method was used to recursively estimate specific discharge in discrete time when temperature measurements were acquired (i.e., hourly) at each discharge location. The methodology used here has been previously tested on both synthetic and field data in McAliley et al. (2022) where EKF methods were shown to converge to step changes in synthetic discharge data on sub-daily timescales, and residuals between observed (i.e., field observations) and estimated (i.e., EKF predictions) temperatures were generally within 0.1°C, consistent with expected measurement precision. Further information on the numerical implementation, comparisons to synthetic and field observations, as well as links to open-source code can be found in McAliley et al. (2022). To complement these estimates, discrete measurements of groundwater discharge were taken using seepage meters directly coupled to the streambed interface. Vertical head gradients were also measured in some seeps and mean hydraulic conductivity values obtained from seepage meter measurements were used to produce estimates of 1D groundwater flux (m/d) from measured head differentials. This release covers data associated with the estimation of groundwater flux from these identified discharge zones using the methods above described above.

The temperature and surface geophysical data contained in this release have primarily been collected to support groundwater/surface water methods development, and to characterize the hydrogeological controls on native brook trout habitat. All data have been collected since 2010 along the Quashnet River corridor located on Cape Cod, MA, USA. Cape Cod is a peninsula in southeastern coastal Massachusetts, USA, composed primarily of highly permeable unconsolidated glacial moraine and outwash deposits. The largest of the Cape Cod sole-source aquifers occupies a western (landward) section of the peninsula, and is incised by several linear valleys that drain groundwater south to the Atlantic Ocean via baseflow-dominated streams. Strong groundwater discharge to the Quashnet River supports a relatively stable flow regime, as monitored by USGS gage 011058837, located at the downstream end of typical field research focus areas. The lower Quashnet River emerges from a narrow sand and gravel valley to a broader area with well-defined lateral floodplains. Historical cranberry farming practices, abandoned in the 1950s, have modified the stream corridor as described by: Barlow, P. M. and Hess, K. M.: Simulated Hydrologic Responses of the Quashnet River Stream-Auquifer System to Proposed Ground-Water Withdrawals, Cape Cod, Massachusetts, U.S. Geol. Surv. Rep. 93-4064, 51, 1993. The Massachusetts Division of Fisheries and Wildlife has been monitoring brook trout populations in the Quashnet River since 1988 and movement since 2007. Groundwater influence on stream temperature is pronounced, particularly over the 2-km reach above the USGS gage, below which stream stage is tidally affected.

The temperature and surface geophysical data contained in this release have primarily been collected to support groundwater/surface water methods development, and to characterize the hydrogeological controls on native brook trout habitat. All data have been collected since 2010 along the Quashnet River corridor located on Cape Cod, MA, USA. Cape Cod is a peninsula in southeastern coastal Massachusetts, USA, composed primarily of highly permeable unconsolidated glacial moraine and outwash deposits. The largest of the Cape Cod sole-source aquifers occupies a western (landward) section of the peninsula, and is incised by several linear valleys that drain groundwater south to the Atlantic Ocean via baseflow-dominated streams. Strong groundwater discharge to the Quashnet River supports a relatively stable flow regime, as monitored by USGS gage 011058837, located at the downstream end of typical field research focus areas. The lower Quashnet River emerges from a narrow sand and gravel valley to a broader area with well-defined lateral floodplains. Historical cranberry farming practices, abandoned in the 1950s, have modified the stream corridor as described by: Barlow, P. M. and Hess, K. M.: Simulated Hydrologic Responses of the Quashnet River Stream-Auquifer System to Proposed Ground-Water Withdrawals, Cape Cod, Massachusetts, U.S. Geol. Surv. Rep. 93-4064, 51, 1993. The Massachusetts Division of Fisheries and Wildlife has been monitoring brook trout populations in the Quashnet River since 1988 and movement since 2007. Groundwater influence on stream temperature is pronounced, particularly over the 2-km reach above the USGS gage, below which stream stage is tidally affected.

Surface geophysical tools remotely sense hydrogeological properties that can control subsurface flow and water quality. There are numerous geophysical tools, for the Quashnet River work we have principally used ground penetrating radar (GPR) and electromagnetic imaging (EMI). The instruments are either hand carried or floated down the stream channel and other cross-sections of the river corridor. Data from various field deployments of GPR and EMI are described and presented here.

Surface geophysical tools remotely sense hydrogeological properties that can control subsurface flow and water quality. There are numerous geophysical tools, for the Quashnet River work we have principally used ground penetrating radar (GPR) and electromagnetic imaging (EMI). The instruments are either hand carried or floated down the stream channel and other cross-sections of the river corridor. Data from various field deployments of GPR and EMI are described and presented here.

In summer in Massachusetts, USA, preferential groundwater discharge zones are often colder than adjacent streambed areas that do not have substantial discharge. Therefore, discharge zones can efficiently be identified and mapped over space using heat as a tracer. This data release contains fiber-optic distributed temperature sensing (FO-DTS) data collected along the streambed interface of the main channel and tributaries of the upper Quashnet River, within approximately 1 km of Johns Pond, from June 14 to June 20, 2020. For these deployments a Salixa XT-DTS control unit (Salixa Ltd, Hertfordshire, UK) was used, and measurements were made over several day increments at 0.508 m linear resolution. Specific locations for collected data are located within the data files, and additional details are contained in the ‘readme’ files within each zipped data directory. Measured data in the form of Salixa instrument files are located in the 'Raw' data directory, including data collected along lengths of optical fiber that were not installed in the streams. The 'Processed' data directory contains data that have been aggregated from the original machine output files, spatially trimmed, and georeferenced. Additionally, simple summary streambed interface temperature statistics (mean, max, min, standard deviation) are listed by streambed location.

In summer in Massachusetts, USA, preferential groundwater discharge zones are often colder than adjacent streambed areas that do not have substantial discharge. Therefore, discharge zones can efficiently be identified and mapped over space using heat as a tracer. This data release contains fiber-optic distributed temperature sensing (FO-DTS) data collected along the streambed interface of the main channel and tributaries of the upper Quashnet River, within approximately 1 km of Johns Pond, from June 14 to June 20, 2020. For these deployments a Salixa XT-DTS control unit (Salixa Ltd, Hertfordshire, UK) was used, and measurements were made over several day increments at 0.508 m linear resolution. Specific locations for collected data are located within the data files, and additional details are contained in the ‘readme’ files within each zipped data directory. Measured data in the form of Salixa instrument files are located in the 'Raw' data directory, including data collected along lengths of optical fiber that were not installed in the streams. The 'Processed' data directory contains data that have been aggregated from the original machine output files, spatially trimmed, and georeferenced. Additionally, simple summary streambed interface temperature statistics (mean, max, min, standard deviation) are listed by streambed location.

In 2015-2016, physicochemical properties and chemical characteristics of stream water, bed sediment, groundwater, and soil were determined in watersheds located outside of, but in proximity to, the Peason Ridge Training Area and Main Post at the Joint Readiness Training Center and Fort Polk boundaries to document background trace element concentrations. Water samples were analyzed for physicochemical properties, major inorganic ions, selected trace elements, and dissolved organic carbon. Selected trace elements included antimony, arsenic, cadmium, copper, iron, lead, manganese, mercury, and zinc. Stream bed-sediment and soil samples were analyzed for major inorganic ions, selected trace elements, and grain size distribution. Surface-water samples were collected near the downstream transect of each stream reach. Monitoring wells were located adjacent to the stream reach and in close proximity to the surface-water sampling sites. Bulk bed-sediment samples were collected during normal low-flow conditions. Each sample consisted of a composite sample from five locations (right edge, left edge, and center of a middle transect, then upstream and downstream of the middle transect) within each stream reach. Three soil samples, one from hilltops, one from side slopes, and one from riparian zones, were collected from areas adjacent to each stream reach. Each soil sample consisted of 5 to 10 grab samples collected by a 21-inch-long, 5/8-inch internal diameter stainless-steel hand auger and composited in Teflon lined pans. All samples were collected following USGS sampling protocols. This data release provides database and mapping information for assessment of trace element concentrations in stream water, bed sediment, groundwater, and soil found in relatively pristine and undisturbed watersheds in proximity to watersheds used for military training.

In 2015-2016, physicochemical properties and chemical characteristics of stream water, bed sediment, groundwater, and soil were determined in watersheds located outside of, but in proximity to, the Peason Ridge Training Area and Main Post at the Joint Readiness Training Center and Fort Polk boundaries to document background trace element concentrations. Water samples were analyzed for physicochemical properties, major inorganic ions, selected trace elements, and dissolved organic carbon. Selected trace elements included antimony, arsenic, cadmium, copper, iron, lead, manganese, mercury, and zinc. Stream bed-sediment and soil samples were analyzed for major inorganic ions, selected trace elements, and grain size distribution. Surface-water samples were collected near the downstream transect of each stream reach. Monitoring wells were located adjacent to the stream reach and in close proximity to the surface-water sampling sites. Bulk bed-sediment samples were collected during normal low-flow conditions. Each sample consisted of a composite sample from five locations (right edge, left edge, and center of a middle transect, then upstream and downstream of the middle transect) within each stream reach. Three soil samples, one from hilltops, one from side slopes, and one from riparian zones, were collected from areas adjacent to each stream reach. Each soil sample consisted of 5 to 10 grab samples collected by a 21-inch-long, 5/8-inch internal diameter stainless-steel hand auger and composited in Teflon lined pans. All samples were collected following USGS sampling protocols. This data release provides database and mapping information for assessment of trace element concentrations in stream water, bed sediment, groundwater, and soil found in relatively pristine and undisturbed watersheds in proximity to watersheds used for military training.