This data release contains extended estimates of daily groundwater levels and monthly percentiles at 27 short-term monitoring wells in Massachusetts. The Maintenance of Variance Extension Type 1 (MOVE.1) regression method was used to extend short-term groundwater levels at wells with less than 10 years of continuous data. This method uses groundwater level data from a correlated long-term monitoring well (index well) to estimate the groundwater level record for the short-term monitoring well. MOVE.1 regressions are used widely throughout the hydrologic community to extend flow records from streamgaging stations but are less commonly used to extend groundwater records at wells. The data in this data release document the results of the MOVE.1 regressions to estimate groundwater levels and compute updated monthly percentiles for select wells used in the groundwater index in the Massachusetts Drought Management Plan (2019). The U.S. Geological Survey (USGS) groundwater identification ...

A method to estimate the probable high groundwater level in Massachusetts, excluding Cape Cod and the Islands was developed in 1981. The method, commonly called the “Frimpter Method,” uses a groundwater measurement from a test site, groundwater measurements from an index well, and a distribution of high groundwater levels from wells in similar geologic and topographic settings. Historic groundwater-level statistics (maximum and 90th percentile groundwater level and annual groundwater-level range) were calculated for 153 wells in Massachusetts and nearby States to update the method inputs. In addition, as part of a comparison of approaches to determine the best index well for a given site, a multiple linear regression equation was developed to explore the relations between predictor variables and the correlations, with the goal of predicting the most highly correlated index well for each test site. This data release includes the calculated groundwater level statistics, the ancillar ...

The data in this tile service is a raster (100-meter resolution) that uses average transmissivity from SURFGEO24K_T_AY, topographic relief, and groundwater recharge to calculate the water table ratio. Positive values indicate that the region has a topography-controlled water table, and negative numbers indicate a recharge-controlled water table. For further methods see Gleeson et al. (2011).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata and map service.

The data in this feature service uses the same polygons as the MassGIS USGS 1:24,000 Surficial Geology data layer and includes minimum, maximum, and average hydraulic conductivity in feet per day for each surficial unit. Hydraulic conductivity values were extracted from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 165 aquifer tests or aggregates of aquifer tests depending on the available data in each report).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).\One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata and the map service.

Groundwater and estuary water levels near Mill Creek and the Herring River in Wellfleet, Massachusetts, were measured from June 2017 to August 2022. The data contained in these datasets consist of tables of updated statistics provided in the original work by Mullaney and others (2020, Appendix 2) and associated data release by Mullaney and Barclay (2020). The data include summary tables of water-level statistics and summary tables of updated statistical coefficients for the models in the original work. The data release also includes the underlying input data sets for these statistical regression models and an update of table 2 from the larger work, which consists of summary statistics of water levels for the period of data analysis from 2017-06-01 to 2022-08-05. Mullaney, J.R., and Barclay, J.R., 2020, Data on Tidally Filtered Groundwater and Estuary Water Levels, and Climatological Data Near Mill Creek and the Herring River, Cape Cod, Wellfleet, Massachusetts, 2017-2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9T167II. Mullaney, J.R., Barclay, J.R., Laabs, K.L., and Lavallee, K.D., 2020, Hydrogeology and interactions of groundwater and surface water near Mill Creek and the Herring River, Wellfleet, Massachusetts, 2017–18: U.S. Geological Survey Scientific Investigations Report 2019–5145, 60 p., https://doi.org/10.3133/sir20195145.

The data in this map service is a raster (100-meter resolution) that uses average transmissivity from SURFGEO24K_T_AY, topographic relief, and groundwater recharge to calculate the water table ratio. Positive values indicate that the region has a topography-controlled water table, and negative numbers indicate a recharge-controlled water table. For further methods see Gleeson et al. (2011).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata.

Groundwater and estuary water levels near Mill Creek, and the Herring River in Wellfleet Massachusetts were measured from June 2017 to June 14, 2018. Water-level data have been filtered to remove the effects of the daily tides. The mean daily value of the tidally filtered 15 minute water-level data is presented. The data also include a composite data set of daily precipitation values, as well as data on the growing degrees days (50 degrees Fahrenheit), from two weather stations on Cape Cod, Massachusetts.

The data in this map service is a polygon feature class (converted from a 100-meter resolution raster dataset) that uses the hydraulic conductivity fields from SURFGEO24K_K_POLY, water table elevation from the statewide groundwater flow model, and bedrock altitude to calculate aquifer yield and minimum, maximum, and average transmissivity in square feet per day. Transmissivity was calculated as hydraulic conductivity multiplied by aquifer thickness. Aquifer thickness was determined by the water table elevation minus bedrock altitude. Transmissivity cutoff values to characterize aquifer yield were from the MassGIS Aquifers layer (AQUIFERS_POLY).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata and the feature service.

This data release provides a comprehensive dataset of sampling-site characteristics and baseline groundwater-quality data collected from a network of multilevel sampling wells installed in a densely developed coastal neighborhood undergoing a conversion from onsite septic systems to municipal sewering. Groundwater samples were collected during multiple events from a total of 227 well screens at 15 locations using a peristaltic pump between June 2016 and March 2024. Samples were collected and preserved following methods documented in the U.S. Geological Survey National Field Manual (variously dated) and Savoie and others (2012). This dataset provides well construction information, groundwater levels, water-quality field parameters, and laboratory results from nutrient and major ion analyses.
Savoie, J.G., LeBlanc, D.R., Fairchild, G.M., Smith, R.L., Kent, D.B., Barber, L.B., Repert, D.A., Hart, C.P., Keefe, S.H., and Parsons, L.A., 2012, Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006–08: U.S. Geological Survey Data Series 648, 11 p, available online at https://pubs.usgs.gov/ds/648/
U.S. Geological Survey, variously dated, National field manual for the collection of water-quality data: U.S. Geological Survey Techniques of Water-Resources Investigations, book 9, chaps. A1-A10, available online at https://pubs.water.usgs.gov/twri9A. First release: March 2019 Revised to include June 2019 and September 2019 data: November 2019 (ver. 2.0) Revised to include January 2020, June 2020, September 2020, and December 2020 data: March 2021 (ver. 3.0) Revised to include June 2021 and September 2021 data: February 2022 (ver. 4.0) Revised to include for February 2022, May 2022, August/September 2022, February 2023, May 2023, August 2023, and March 2024 data: May 2024 (ver. 5.0)

The data in this feature service is a polygon feature class (converted from a 100-meter resolution raster dataset) that uses the hydraulic conductivity fields from SURFGEO24K_K_POLY, water table elevation from the statewide groundwater flow model, and bedrock altitude to calculate aquifer yield and minimum, maximum, and average transmissivity in square feet per day. Transmissivity was calculated as hydraulic conductivity multiplied by aquifer thickness. Aquifer thickness was determined by the water table elevation minus bedrock altitude. Transmissivity cutoff values to characterize aquifer yield were from the MassGIS Aquifers layer (AQUIFERS_POLY).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata and the map service.

An existing, three-dimensional, transient groundwater-flow model of the Upper Charles River Basin, eastern Massachusetts, was modified to evaluate alternative groundwater-withdrawal scenarios on water levels in Kingsbury Pond. The pond is hydraulically connected to the groundwater-flow system, and water levels in the pond fluctuate in response to recharge to the aquifer from precipitation and wastewater return flows through septic systems, to withdrawals from the aquifer at nearby wells, and to precipitation directly on the pond surface. Concerns about the effects of groundwater withdrawals on water levels in the pond prompted an investigation by the U.S. Geological Survey (USGS) in cooperation with the Massachusetts Department of Environmental Protection to better understand the hydrology of Kingsbury Pond and its response to withdrawals. The goal of the study was to determine if withdrawals from wells in Franklin, Massachusetts, can be modified to simultaneously reduce the effect on water levels in the pond and yet meet the water-supply demands of the Town of Franklin. The model, which uses MODFLOW-2000, simulates flow within the surficial deposits and groundwater interactions with surface water in the basin. The model was modified for the study near Kingsbury Pond to improve representation of the hydrologic system near the pond. A groundwater-management model that links the groundwater-flow model with a mathematical-optimization method (referred to as the response-matrix method) was developed to evaluate the effects of three alternative groundwater-withdrawal scenarios for the Franklin public-water system on water levels in Kingsbury Pond. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20235083).

The U.S. Geological Survey, in cooperation with the Town of Barnstable, Massachusetts, modified an existing numerical, steady-state regional MODFLOW-2005 groundwater-flow model to evaluate changes in water levels from a reference condition (2015) for nine pumping and wastewater return flow scenarios prepared by the Hyannis Water System.

The three-dimensional, steady-state groundwater-flow model used to simulate water level changes is a modified and recalibrated version of an existing model that was used to simulate the potential effects of sea-level rise on groundwater levels of the Sagamore and Monomoy freshwater lenses of the Cape Cod aquifer (Walter and others, 2016) (https://doi.org/10.3133/sir20165058). Two modifications, (1) the addition of spatially variable natural recharge from precipitation, and (2) a revised representation of wastewater return-flow recharge to septic systems in the Town of Barnstable, were made to the existing regional groundwater-flow mode ...

The U.S. Geological Survey (USGS) assisted the Massachusetts Department of Environmental Protection (MassDEP) with the Massachusetts Estuary Project (MEP), by delineating groundwater-contributing areas to various hydrologic features including ponds, streams, and coastal water bodies, throughout southeastern Massachusetts. These contributing areas were delineated over a 6-year period from 2003 to 2008 using previously published USGS groundwater-flow models for the Plymouth-Carver region (Masterson and others, 2009), the Sagamore (western) and Monomoy (eastern) flow lenses of Cape Cod (Walter and Whealan, 2005), and lower Cape Cod (Masterson, 2004). The original USGS groundwater-contributing areas were subsequently revised in some locations by the MEP to remove modeling artifacts or to make the contributing areas more consistent with site-specific hydrologic features or streamflow data. The data series report (Carlson and others, 2017; refer to the section below) associated with this data release describes the process used to create the USGS groundwater-contributing areas and this data release serves to publish those model results in their original format in a single, publicly accessible publication. This data release contains shapefiles of groundwater-contributing areas and the outline of each model area in the following folders available for downloading: 'LowerCape' 'Monomoy' 'PlyCar' 'Sagamore' ‘Ancillary’. The shapefiles in these folders are aggregated in an ArcMap project, "USGS_original_contributing_areas_PlyCar_CapeCod_shapefiles.mxd", which is included in this data release and organizes the shapefiles for all groundwater-contributing areas for each model area for the Plymouth-Carver region and Cape Cod. A readme.txt file is also included that describes the file folders associated with each model area. These groundwater-contributing areas are associated with the following publications: Carlson, C.S., Masterson, J.P., Walter, D.A., and Barbaro, J.R., 2017, Development of simulated groundwater-contributing areas to selected streams, ponds, coastal water bodies, and production wells in the Plymouth-Carver region and Cape Cod, Massachusetts: U.S. Geological Survey Data Series 1074, 17 p. [Also available at https://doi.org/10.3133/ds1074.] Masterson, J.P., Carlson, C.S., and Walter, D.A., 2009, Hydrogeology and simulation of groundwater flow in the Plymouth-Carver-Kingston-Duxbury aquifer system, southeastern Massachusetts: U.S. Geological Survey Scientific Investigations Report 2009–5063, 110 p. [Also available at http://pubs.er.usgs.gov/publication/sir20095063.] Walter, D.A., and Whealan, A.T., 2005, Simulated water sources and effects of pumping on surface and ground water, Sagamore and Monomoy flow lenses, Cape Cod, Massachusetts: U.S. Geological Survey Scientific Investigations Report 2004-5181, 85 p. [Also available at http://pubs.usgs.gov/sir/2004/5181/]. Masterson, J.P., 2004, Simulated interaction between freshwater and saltwater and effects of ground-water pumping and sea-level change, Lower Cape Cod aquifer system, Massachusetts: U.S. Geological Survey Scientific Investigations Report 2004-5014, 78 p. [Also available at http://pubs.usgs.gov/sir/2004/5014/].

A dataset of well information and geospatial data was developed for 426 U.S. Geological Survey (USGS) observation wells in Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. An extensive list of attributes is included about each well, its location, and water-level history to provide the public and water-resources community with comprehensive information on the USGS well network in New England and data available from these sites. These data may be useful for evaluating groundwater conditions and variability across the region. The well list and site attributes, which were extracted from USGS National Water Information System (NWIS), represent all of the active wells in the New England network up to the end of 2017, and an additional 45 wells that were inactive (discontinued or replaced by a nearby well) at that time. Inactive wells were included in the database because they (1) contain periods of water-level record that may be useful for groundwater assessments, (2) may become active again at some point, or (3) are being monitored by another agency (most discontinued New Hampshire wells are still being monitored and the data are available in the National Groundwater Monitoring Network (https://cida.usgs.gov/ngwmn/index.jsp). The wells in this database have been sites of water-level data collection (periodic levels and/or continuous levels) for an average of 31 years. Water-level records go back to 1913. The groundwater-level statistics included in the dataset represent hydrologic conditions for the period of record for inactive wells, or through the end of water year 2017 (September 30, 2017) for active wells. Geographic Information Systems (GIS) data layers were compiled from various sources and dates ranging from 2003 to 2018. These GIS data were used to calculate attributes related to topographic setting, climate, land cover, soil, and geology giving hydrologic and environmental context to each well. In total, the data include 90 attributes for each well. In addition to site number and station name, attributes were developed for site information (15 attributes); groundwater-level statistics through water year 2017 (16 attributes); well-construction information (9 attributes); topographic setting (11 attributes); climate (2 attributes); land use and cover (17 attributes); soils (4 attributes); and geology (14 attributes). Basic well and site information includes well location, period of record, well-construction details, continuous versus intermittent data collection, and ground altitudes. Attributes that may influence groundwater levels include: well depth, location of open or screened interval, aquifer type, surficial and bedrock geology, topographic position, flow distance to surface water, land use and cover near the well, soil texture and drainage, precipitation, and air temperature.

Environmental parameters affecting plant productivity and microbial respiration, such as water level, salinity, and groundwater temperature included in these datasets, are key components of wetland carbon cycling, carbon storage, and capacity to maintain elevation. Data were collected to (1) provide background data to evaluate potential differences in water level and carbon flux between wetland sites with differing elevation and tidal inundation and (2) facilitate applications of Blue Carbon projects in coastal wetlands. Associated child pages include continuous water level, salinity, and temperature from shallow wells installed in coastal wetland sites on Cape Cod, Massachusetts. These datasets are grouped by the project they support or by study site. Project study sites include salt marshes with natural tidal flow, salt marshes that were previously tidally restricted and have been restored, impounded coastal wetlands with restricted tidal flow inclusive of various vegetation typ ...

The data in this map service uses the same polygons as the MassGIS 1:250,000 Surficial Geology data layer (SURFGEO250K_POLY) and includes minimum, maximum, and average specific yield for each surficial unit. Specific yield values were extracted from U.S. Geological Survey groundwater reports and Morris & Johnson (1967) (a total of 60 aquifer tests).The Hydrogeologic Atlas of Massachusetts provides data on the hydraulic properties of the statewide surficial aquifers. The datasets were developed using surficial geology, bedrock altitude, a statewide groundwater flow model, and a compilation of hydraulic property data from U.S. Geological Survey groundwater reports, Massachusetts Department of Environmental Protection Zone II reports, and other Massachusetts-specific journal articles (a total of 23 sources).One of the goals of this project was to understand current and projected future groundwater flooding risks across the state. To understand groundwater flooding risks, we developed a statewide three-dimensional groundwater flow model to simulate the water table elevation. The Hydrogeologic Atlas of Massachusetts compiles new datasets developed as input into the groundwater model, groundwater model simulation results, and other statewide map products created through this project. For further information regarding the methods of this study see Corkran et al. (2024), a report submitted to the Massachusetts Executive Office of Energy and Environmental Affairs.Suggested Citation:Corkran, D., Kirshen, A., Moran, B.J., Blin, N., King, R., Bresee, M., & Boutt, D. (2024). Massachusetts State-wide Groundwater Model and Flooding Risk Assessment 1.0. Report funded by the Massachusetts Executive Office of Energy and Environmental Affairs and published on the ResilientMass website.See full metadata and the feature service.

This data release contains well yield and ancillary data for 7,287 bedrock wells used in an analysis of bedrock well yield in the Nashoba Terrane and surrounding area in eastern and central Massachusetts. The data release also contains Geographic Information System (GIS) data layers of lineaments delineated from aerial photographs and digital elevation data for a part of the Nashoba Terrane study area. Ancillary data consist of well depth; bedrock geology, surficial geology, topographic setting, and wetlands at the well location; distance of the well to hydrologic and geologic features; and distance of the well to lineaments. The data were interpreted in U.S. Geological Survey Scientific-Investigations Report 2012-5155, and a data layer of estimated well yield in 200 by 200 meter grid cells throughout the Nashoba Terrane and surrounding area, based on kriging of yield data from the 7,287 wells, is included in the data release. The data release contains 4 separate items: 1. Well yield and ancillary data for 7,287 bedrock wells 2. Well locations 3. Lineaments in a part of the study area 4. Estimated bedrock well yield from kriging of well yield data These data are associated with the following publication: DeSimone, L.A., and Barbaro, J.R., 2012, Yield of bedrock wells in the Nashoba terrane, central and eastern Massachusetts: U.S. Geological Survey Scientific Investigations Report 2012-5155, 74 p., available at http://pubs.usgs.gov/sir/2012/5155

The USGS compiles online access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, Puerto Rico, the Virgin Islands, Guam, American Samoa and the Commonwealth of the Northern Mariana Islands.

This U.S. Geological Survey (USGS) data release provides a comprehensive dataset of water-quality results, physical-parameter measurements, hydrologic measurements, and site information collected to study the nature and extent of water quality along groundwater flow paths adjacent to glacial-kettle lakes on Cape Cod, Massachusetts. Water-quality samples were collected in 2003, 2005, and 2012 through 2018 in and near seven kettle lakes located on western Cape Cod, with most of the data collected in 2015-2017 from Ashumet Pond, which is located in the towns of Falmouth and Mashpee. Data were also collected at other lakes to compare the lake-specific influences of geochemistry and hydrology on the downgradient groundwater systems. Samples were collected over the course of multi-day and multi-month sampling events to capture the influence of annual and diel changes in the lakes. Water-quality results are presented for groundwater samples collected from monitoring wells and multilevel samplers (MLS) located downgradient from the lakes; shallow groundwater samples from beneath the lake bottoms (also referred to herein as porewater samples) collected near shore by using microwells, also known as pushpoints (manufactured by M.H.E. Products1), installed 5-100 centimeters below the lake-bottom surface into known groundwater upwelling and lake-water downwelling zones near the lake shore; grab samples of lake water collected in conjunction with the near-shore groundwater samples; and profiles of the lake water column collected in deeper parts of the lake basins. The data include field water-quality measurements of specific conductance, pH, dissolved oxygen, temperature, and alkalinity (incremental field titration method) using single-parameter field probes as well as multiprobe sondes; concentrations of samples collected for selected organic and inorganic solutes, including major cations and anions, minor elements, nitrate, nitrite, ammonium, total dissolved nitrogen, dissolved organic carbon, and dissolved inorganic carbon; concentrations of dissolved gases, including nitrous oxide and methane, absorbance of ultraviolet/visible light; stable isotopic ratios of carbon (delta 13C, d13C) measured in dissolved inorganic carbon; isotope ratios of oxygen (d18O) and hydrogen (d2H) measured in water; isotope ratios of oxygen (d18O) and nitrogen (d15N) measured in nitrate plus nitrite; and isotope ratios of oxygen (d18O) measured in dissolved oxygen gas. The data release also includes results from analyses of sediment-core material collected from the sediment surface to 30 centimeters below the lake bottom, and analyses of aquatic vegetation and biofilms on pebble surfaces in Ashumet Pond. The sediment-core results include total carbon and nitrogen content of dried organic material scraped from the pebbles, d13C and d15N of carbon and nitrogen of the organic matter, extractions of ammonium, and carbon dioxide and oxygen measurements used to estimate potential respiration rates from incubation experiments. The data are compiled into ten Excel (.xlsx) tables: (1) A summary of all the sampling event names and dates (Summary Sampling Events.xlsx), (2) sample information, field measurements, and results from laboratory water-quality analyses for environmental samples collected from monitoring wells, MLSs, lake-basin profiles, and near-shore pushpoints (Water Quality Samples.xlsx), (3) results from selected water-quality analytes for laboratory duplicates, laboratory blanks, and equipment rinseate samples (QAQC Samples.xlsx), (4) distance from shore and lake-stage measurements for Ashumet Pond pushpoint site ASHPD-GWOUT-R-N at select times used in a regression equation to estimate distance to shore, and measured distances between pushpoint, MLS, and well locations relative to site ASHPD-GWOUT-R-N (Distance Calculations.xlsx), (5) approximate water-level altitudes at monitoring well and MLS sites calculated from water-level measurements made at water-table wells concurrent to water-quality sampling (Approximate Well Water Level.xlsx), (6) carbon and nitrogen concentrations and d13C and d15N of sediment cores, aquatic vegetation, and pebble scrapings collected at Ashumet Pond (ASHPD Sediment.xlsx), (7) d18O of dissolved oxygen and water in selected groundwater samples (O2 Isotopes.xlsx), (8) details of experiments to measure potential rates of carbon dioxide and oxygen production and consumption in selected groundwater samples (CO2 & O2 Rates.xlsx), (9) sediment extractions of ammonium using potassium chloride in selected groundwater samples (KCl Extractions.xlsx), and (10) field water-quality measurements made using multiprobe sondes at Ashumet, Santuit, and Shubael Ponds (Continuous Sonde Data.xlsx). A data dictionary file describes the entities, attributes, reporting limits, uncertainties, minimum and maximum values, analytical instruments, methods, and citations for the tables (1-10) in the dataset (Data Dictionary.xlsx). This dataset is complemented by surface-water and groundwater temperature records and lakebed seepage data from in and near several western Cape Cod lakes, which are documented in the following data release: Hull, R.B., Briggs, M., LeBlanc, D.R., Armstrong, D.A., McCobb, T.D., Temperature and seepage data from the lake-bottom of groundwater flow-through kettle hole lakes, western Cape Cod, MA, 2015 - 2018: U.S. Geological Survey data release, https://doi.org/10.5066/P9QLIFWV. 1 Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

The USGS compiles online access to water-resources data collected at approximately 1.5 million sites in all 50 States, the District of Columbia, Puerto Rico, the Virgin Islands, Guam, American Samoa and the Commonwealth of the Northern Mariana Islands.