This data release documents spatiotemporal water-quality, landscape, and climatic conditions in Fairfax County, Virginia from 2007 through 2018. These data were used to evaluate the water-quality and ecological condition of 20 Fairfax County watersheds monitored since 2007. Data include measures of water-quality, precipitation, air temperature, land use, land cover, wastewater and stormwater infrastructure, soil properties, geologic setting, and stream networks. Annual values from 2007 through 2018 are reported for data expected to change over time. Watershed-specific values are reported for data that differ across the landscape. Annual values for the 20 study watersheds and Fairfax County are reported in the file "Spatiotemporal Predictors.csv". A description of each spatiotemporal variable, including data sources, are provided in the file "Data Dictionary.csv".

This data release contains summary metrics describing stream stage, stream water temperature, and short-term climate conditions (daily precipitation and air temperature) for 30 streams spanning gradients of forest and pasture land uses and agricultural best management practice implementation in the Shenandoah Valley region of Virginia and West Virginia, USA. This setting is the first of four settings or "typologies" that will be assessed for the USGS Chesapeake Stream Team project. High-frequency stage and water temperature (5-minute data), and air temperature (30-minute data) were measured by the U.S. Geological Survey (USGS) from May 2021 to December 2021 and are available on the USGS National Water Information System (NWIS). Stream stage, water temperature, and air temperature data for each of the 30 sites were downloaded from NWIS. Additional daily air temperature and precipitation data were acquired from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data website. Air temperature and water temperature data were used to compute stream water temperature metrics describing stream temperature conditions in each stream during the monitoring period. Stream stage and precipitation data were used to derive stream stage metrics describing stage conditions (a surrogate for flow) for each stream during the monitoring period. Precipitation and air temperature data from PRISM were also used to compute air temperature metrics and precipitation metrics describing climate conditions during the monitoring period. The metrics include: Air temperature metrics - Mean daily minimum, mean, and maximum air temperature Precipitation metrics - Total precipitation depth - Maximum daily precipitation depth - Average precipitation depth per days with precipitation - Frequency of precipitation days Stream stage metrics - Number of runoff events - Frequency of runoff events - Standard deviation in unit-value stage - Coefficient of variation of unit-value stage Stream water temperature metrics - Coefficient of variation of mean and maximum daily water temperatures - Number of days with temperatures of 20 or 25 degrees Celsius or greater - Duration of time above 20 or 25 degrees Celsius or greater - Maximum of seven-day moving average of daily maximum temperature - Mean of daily minimum, maximum, and daily water temperature range - A thermal sensitivity metric, which is the slope estimate from linear regression model of mean daily water temperature versus mean daily air temperature This data release contains six files: 1. "Readme.pdf": This is an expanded narrative describing the methods by which the input data were compiled and screened, and metrics were computed 2. "typology_1_temperature_stage_climate_metric_data_dictionary.csv": This file contains descriptions of each metric and the time periods for which they were computed in the “typology_1_temperature_stage_climate_summary_metrics.csv" file 3. "typology_1_temperature_stage_climate_summary_metrics.csv": This file contains stream temperature metrics, stage metrics, and climate summary metrics for each of the 30 stream sites for different time periods within the overall monitoring period. 4. "typology_1_input_data_high_frequency_temperature_and_stage.zip": This zipped folder contains 30 .csv files, which contain the high-frequency stage, water temperature, and air temperature data collected at each of the 30 stream sites. The file names include the siteID, which is the four-letter site identification listed in the "typology_1_temperature_stage_climate_summary_metrics.csv" file. 5. "typology_1_input_data_daily_climate.csv": This file contains daily climate estimates (precipitation depth, daily minimum, mean, and maximum air temperatures) from PRISM paired to each of the 30 sites. 6. "typology_1_runoff_events.csv": This file contains the stage rise and precipitation data used for some of the stage metric computations.

This data release contains summary metrics describing stream stage, stream water temperature, and short-term climate conditions (daily precipitation and air temperature) for 30 streams spanning gradients of forest and pasture land uses and agricultural best management practice implementation in the Shenandoah Valley region of Virginia and West Virginia, USA. This setting is the first of four settings or "typologies" that will be assessed for the USGS Chesapeake Stream Team project. High-frequency stage and water temperature (5-minute data), and air temperature (30-minute data) were measured by the U.S. Geological Survey (USGS) from May 2021 to December 2021 and are available on the USGS National Water Information System (NWIS). Stream stage, water temperature, and air temperature data for each of the 30 sites were downloaded from NWIS. Additional daily air temperature and precipitation data were acquired from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data website. Air temperature and water temperature data were used to compute stream water temperature metrics describing stream temperature conditions in each stream during the monitoring period. Stream stage and precipitation data were used to derive stream stage metrics describing stage conditions (a surrogate for flow) for each stream during the monitoring period. Precipitation and air temperature data from PRISM were also used to compute air temperature metrics and precipitation metrics describing climate conditions during the monitoring period. The metrics include: Air temperature metrics - Mean daily minimum, mean, and maximum air temperature Precipitation metrics - Total precipitation depth - Maximum daily precipitation depth - Average precipitation depth per days with precipitation - Frequency of precipitation days Stream stage metrics - Number of runoff events - Frequency of runoff events - Standard deviation in unit-value stage - Coefficient of variation of unit-value stage Stream water temperature metrics - Coefficient of variation of mean and maximum daily water temperatures - Number of days with temperatures of 20 or 25 degrees Celsius or greater - Duration of time above 20 or 25 degrees Celsius or greater - Maximum of seven-day moving average of daily maximum temperature - Mean of daily minimum, maximum, and daily water temperature range - A thermal sensitivity metric, which is the slope estimate from linear regression model of mean daily water temperature versus mean daily air temperature This data release contains six files: 1. "Readme.pdf": This is an expanded narrative describing the methods by which the input data were compiled and screened, and metrics were computed 2. "typology_1_temperature_stage_climate_metric_data_dictionary.csv": This file contains descriptions of each metric and the time periods for which they were computed in the “typology_1_temperature_stage_climate_summary_metrics.csv" file 3. "typology_1_temperature_stage_climate_summary_metrics.csv": This file contains stream temperature metrics, stage metrics, and climate summary metrics for each of the 30 stream sites for different time periods within the overall monitoring period. 4. "typology_1_input_data_high_frequency_temperature_and_stage.zip": This zipped folder contains 30 .csv files, which contain the high-frequency stage, water temperature, and air temperature data collected at each of the 30 stream sites. The file names include the siteID, which is the four-letter site identification listed in the "typology_1_temperature_stage_climate_summary_metrics.csv" file. 5. "typology_1_input_data_daily_climate.csv": This file contains daily climate estimates (precipitation depth, daily minimum, mean, and maximum air temperatures) from PRISM paired to each of the 30 sites. 6. "typology_1_runoff_events.csv": This file contains the stage rise and precipitation data used for some of the stage metric computations.

Metrics describing watershed hydrology, stream hydraulics, stream geomorphology, physicochemical processes, and aquatic biology were used to assess a 1.72 km reach of stream above the U.S. Geological Surveys (USGS) Flatlick Branch (station ID 01656903) monitoring station restored using natural channel design. The monitoring station has been continually operated since the start of water year 2008 (water years begin October 1, end September 30th, and are named for the year in which they end). The stream restoration was constructed and completed in water year 2018, and the assessment uses a pre- versus post-restoration study design. The study period spans water year 2008 through 2024. Hydrologic metrics derived from data retrieved from the National Water Information System are provided. Hydraulic metrics are supported by semi-annual cross-sectional surveys collected by USGS staff following standard procedures (Noll and Rylund, 2020). Nutrient and suspended sediment concentrations and loads were computed using a surrogate (multiple-linear regression) approach with lab analyzed nitrogen, phosphorus, and suspended sediment samples as the response variable and basic water-quality parameters (e.g. turbidity, specific conductance, water temperature, pH), streamflow, a baseflow separation Boolean term, and time and seasonal terms as predictor (surrogate) variables. Load results represent the mass of nitrogen, phosphorus, and suspended sediment exported from the watershed. Calibration data, high-frequency surrogate timeseries, and model coefficients, diagnostics, and residuals are provided for each model. High-frequency estimates of concentration and load are provided for all nutrient and sediment constituents. Fairfax County collected benthic macroinvertebrate and habitat data annually, and fish data triennially. These data were used to compute numerous geomorphological and biological metrics and explore patterns and trends before and after the stream restoration. This data release contains seventeen comma-delimited (.csv) files with corresponding data dictionary files (.csv), one text (.txt) file with corresponding data dictionary file (.csv), and one R script. • AEP.csv contains annual exceedance probabilities for peak streamflows derived with the USGS program PeakFQ version 7.2. • Benthic_macroinvertebrates.csv contains raw, field collected benthic macroinvertebrate counts classified by taxonomic hierarchy. Data were collected by Fairfax County. • Benthic_scores.csv contains benthic macroinvertebrate annual scores for 31 metrics describing assemblage richness and composition, and the Fairfax County index of biotic integrity (IBI). • Cross-sections_annual.csv contains annual cross-sectional survey data collected at the monitored cross-section at Flatlick Branch (USGS Station ID 01656903). • Cross-sections_average.csv contains two cross-sections. Each an average of channel cross-sections in the pre-restoration (2008-2017) or post-restoration (2019-2024) periods. • Depth.csv contains an estimate of channel depth based on data collected during manual streamflow measurements from water year 2008 through 2024. • Fish.csv contains fish survey data collected by Fairfax County triennially at Flatlick Branch and Frog Branch. • Floodplain_innundation_events.csv contains gage height data used to quantify the number and duration of events when streamflows exceeded the left bank elevation, causing floodplain inundation. • Floodplain_innundation_event_duration.csv contains the duration, in hours, of each event when streamflows exceeded the left bank elevation, causing floodplain inundation. • Floodplain_innundation_annual_duration.csv contains the total duration, in hours, of each water year when streamflows exceeded the left bank elevation, causing floodplain inundation. • Habitat.csv contains habitat metrics collected by Fairfax County annually at Flatlick Branch and Frog Branch. Habitat assessments are conducted in the late summer or early fall

Watersheds within Fairfax County. There are 30 watersheds delineated across Fairfax County.

This data release contains summary metrics describing stream stage, stream water temperature, and short-term climate conditions (daily precipitation and air temperature) for 30 streams spanning gradients of forest and row-crop land uses and agricultural best management practice implementation in the Delmarva Peninsula of Delaware, Maryland, and Virginia, USA. This setting is the second of four settings, or "typologies," that will be assessed for the U.S. Geological Survey (USGS) Chesapeake Stream Team project. High-frequency stage, water temperature, and air temperature (approximately 15-minute data) were measured by the USGS from March 2022 to September 2022 and are available at McFarland and others (2024). Additional daily air temperature and precipitation data were acquired from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data website (PRISM Climate Group, 2014). Air temperature and water temperature data were used to compute stream water temperature metrics describing stream temperature conditions in each stream during the monitoring period. Stream stage and precipitation data were used to compute stream stage metrics describing stage conditions (a surrogate for streamflow) for each stream during the monitoring period. Precipitation and air temperature data from PRISM were also used to compute air temperature metrics and precipitation metrics describing climate conditions during the monitoring period. The metrics include: Air temperature metrics - Mean daily minimum, mean, and maximum air temperature Precipitation metrics - Total precipitation depth - Maximum daily precipitation depth - Average precipitation depth per days with precipitation - Frequency of precipitation days Stream stage metrics - Number of runoff events - Frequency of runoff events - Standard deviation in unit-value stage Stream water temperature metrics - Coefficient of variation of mean and maximum daily water temperatures - Number of days with temperatures of 20 or 25 degrees Celsius or greater - Duration of time above 20 or 25 degrees Celsius or greater - Maximum of seven-day moving average of daily maximum temperature - Mean of daily minimum, maximum, and daily water temperature range - A thermal sensitivity metric, which is the slope estimate from linear regression model of mean daily water temperature versus mean daily air temperature This data release contains six files: 1. "Readme.pdf": This is an expanded narrative describing the methods by which the input data were compiled and screened, and metrics were computed. 2. "typology_2_temperature_stage_climate_metric_data_dictionary.csv": This file contains descriptions of each metric and the time periods for which they were computed in the "typology_2_temperature_stage_climate_summary_metrics.csv" file. 3. "typology_2_temperature_stage_climate_summary_metrics.csv": This file contains stream temperature metrics, stage metrics, and climate summary metrics for each of the 30 stream sites for different time periods within the overall monitoring period. 4. "typology_2_input_data_high_frequency_temperature_and_stage.zip": This zipped folder contains 30 .csv files, which contain the high-frequency stage, water temperature, and air temperature data collected at each of the 30 stream sites. The file names include the SiteID, a unique four-letter site identification listed in the "typology_2_temperature_stage_climate_summary_metrics.csv" file. 5. "typology_2_input_data_daily_climate.csv": This file contains daily climate estimates (precipitation depth, daily minimum, mean, and maximum air temperatures) from PRISM paired to each of the 30 sites. 6. "typology_2_runoff_events.csv": This file contains the stage rise and precipitation data used for some of the stage metric computations.

This data release contains summary metrics describing stream stage, stream water temperature, and short-term climate conditions (daily precipitation and air temperature) for 30 streams spanning gradients of forest and pasture land uses and agricultural best management practice implementation in the Shenandoah Valley region of Virginia and West Virginia, USA. This setting is the first of four settings or "typologies" that will be assessed for the USGS Chesapeake Stream Team project. High-frequency stage and water temperature (5-minute data), and air temperature (30-minute data) were measured by the U.S. Geological Survey (USGS) from May 2021 to December 2021 and are available on the USGS National Water Information System (NWIS). Stream stage, water temperature, and air temperature data for each of the 30 sites were downloaded from NWIS. Additional daily air temperature and precipitation data were acquired from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data website. Air temperature and water temperature data were used to compute stream water temperature metrics describing stream temperature conditions in each stream during the monitoring period. Stream stage and precipitation data were used to derive stream stage metrics describing stage conditions (a surrogate for flow) for each stream during the monitoring period. Precipitation and air temperature data from PRISM were also used to compute air temperature metrics and precipitation metrics describing climate conditions during the monitoring period. The metrics include: Air temperature metrics - Mean daily minimum, mean, and maximum air temperature Precipitation metrics - Total precipitation depth - Maximum daily precipitation depth - Average precipitation depth per days with precipitation - Frequency of precipitation days Stream stage metrics - Number of runoff events - Frequency of runoff events - Standard deviation in unit-value stage - Coefficient of variation of unit-value stage Stream water temperature metrics - Coefficient of variation of mean and maximum daily water temperatures - Number of days with temperatures of 20 or 25 degrees Celsius or greater - Duration of time above 20 or 25 degrees Celsius or greater - Maximum of seven-day moving average of daily maximum temperature - Mean of daily minimum, maximum, and daily water temperature range - A thermal sensitivity metric, which is the slope estimate from linear regression model of mean daily water temperature versus mean daily air temperature This data release contains six files: 1. "Readme.pdf": This is an expanded narrative describing the methods by which the input data were compiled and screened, and metrics were computed 2. "typology_1_temperature_stage_climate_metric_data_dictionary.csv": This file contains descriptions of each metric and the time periods for which they were computed in the “typology_1_temperature_stage_climate_summary_metrics.csv" file 3. "typology_1_temperature_stage_climate_summary_metrics.csv": This file contains stream temperature metrics, stage metrics, and climate summary metrics for each of the 30 stream sites for different time periods within the overall monitoring period. 4. "typology_1_input_data_high_frequency_temperature_and_stage.zip": This zipped folder contains 30 .csv files, which contain the high-frequency stage, water temperature, and air temperature data collected at each of the 30 stream sites. The file names include the siteID, which is the four-letter site identification listed in the "typology_1_temperature_stage_climate_summary_metrics.csv" file. 5. "typology_1_input_data_daily_climate.csv": This file contains daily climate estimates (precipitation depth, daily minimum, mean, and maximum air temperatures) from PRISM paired to each of the 30 sites. 6. "typology_1_runoff_events.csv": This file contains the stage rise and precipitation data used for some of the stage metric computations.

This data release contains summary metrics describing stream stage, stream water temperature, and short-term climate conditions (daily precipitation and air temperature) for 30 streams spanning gradients of forest and row-crop land uses and agricultural best management practice implementation in the Delmarva Peninsula of Delaware, Maryland, and Virginia, USA. This setting is the second of four settings, or "typologies," that will be assessed for the U.S. Geological Survey (USGS) Chesapeake Stream Team project. High-frequency stage, water temperature, and air temperature (approximately 15-minute data) were measured by the USGS from March 2022 to September 2022 and are available at McFarland and others (2024). Additional daily air temperature and precipitation data were acquired from the Parameter-elevation Regressions on Independent Slopes Model (PRISM) climate data website (PRISM Climate Group, 2014). Air temperature and water temperature data were used to compute stream water temperature metrics describing stream temperature conditions in each stream during the monitoring period. Stream stage and precipitation data were used to compute stream stage metrics describing stage conditions (a surrogate for streamflow) for each stream during the monitoring period. Precipitation and air temperature data from PRISM were also used to compute air temperature metrics and precipitation metrics describing climate conditions during the monitoring period. The metrics include: Air temperature metrics - Mean daily minimum, mean, and maximum air temperature Precipitation metrics - Total precipitation depth - Maximum daily precipitation depth - Average precipitation depth per days with precipitation - Frequency of precipitation days Stream stage metrics - Number of runoff events - Frequency of runoff events - Standard deviation in unit-value stage Stream water temperature metrics - Coefficient of variation of mean and maximum daily water temperatures - Number of days with temperatures of 20 or 25 degrees Celsius or greater - Duration of time above 20 or 25 degrees Celsius or greater - Maximum of seven-day moving average of daily maximum temperature - Mean of daily minimum, maximum, and daily water temperature range - A thermal sensitivity metric, which is the slope estimate from linear regression model of mean daily water temperature versus mean daily air temperature This data release contains six files: 1. "Readme.pdf": This is an expanded narrative describing the methods by which the input data were compiled and screened, and metrics were computed. 2. "typology_2_temperature_stage_climate_metric_data_dictionary.csv": This file contains descriptions of each metric and the time periods for which they were computed in the “typology_2_temperature_stage_climate_summary_metrics.csv" file. 3. "typology_2_temperature_stage_climate_summary_metrics.csv": This file contains stream temperature metrics, stage metrics, and climate summary metrics for each of the 30 stream sites for different time periods within the overall monitoring period. 4. "typology_2_input_data_high_frequency_temperature_and_stage.zip": This zipped folder contains 30 .csv files, which contain the high-frequency stage, water temperature, and air temperature data collected at each of the 30 stream sites. The file names include the SiteID, a unique four-letter site identification listed in the "typology_2_temperature_stage_climate_summary_metrics.csv" file. 5. "typology_2_input_data_daily_climate.csv": This file contains daily climate estimates (precipitation depth, daily minimum, mean, and maximum air temperatures) from PRISM paired to each of the 30 sites. 6. "typology_2_runoff_events.csv": This file contains the stage rise and precipitation data used for some of the stage metric computations.

Datasets used to quantify and value the ecosystem service of sediment and nutrient retention for floodplains within the Difficult Run watershed located in Fairfax County, Virginia. Geospatial datasets include a digital elevation model (DEM), a hydrologically conditioned DEM, output from the USGS Stream Channel and Floodplain Metric Toolbox, and field data sets used to develop regression models to predict sediment and nutrient retention services for stream within the Difficult Run watershed.

Datasets used to quantify and value the ecosystem service of sediment and nutrient retention for floodplains within the Difficult Run watershed located in Fairfax County, Virginia. Geospatial datasets include a digital elevation model (DEM), a hydrologically conditioned DEM, output from the USGS Stream Channel and Floodplain Metric Toolbox, and field data sets used to develop regression models to predict sediment and nutrient retention services for stream within the Difficult Run watershed.