Data provided from the Virginia Department of Environmental Quality (DEQ) including simulated values of 72 hydrologic metrics, or indicators of hydrologic alteration (IHA), 37 fish metrics, and 64 benthic invertebrate metrics were reviewed to assess significant flow-ecology relations that may be developed. Hydrologic alteration was represented by simulation of streamflow record for a pre-water-withdrawal condition (baseline) without dams or developed land, compared to the simulated recent-flow condition (2008) including withdrawals, dams and altered landscape to calculate a percent-alteration of flow. Biological samples used represent a median condition of the biological community from 1972 to 2010. This study reviewed more than 7,272 linear regression models that relate altered flow conditions to biological sample metrics in Virginia. Decreasing flow conditions were the focus of this evaluation because of their relevance to the water-supply permitting process. The data tables highlight relations which may be significant and useful in future study and were further explored in the companion report; and relations that do not meet basic assumptions for valid linear regressions which were noted and omitted from the companion report. The three regions in Virginia defined by major drainage and physiographic boundaries as the Ohio River Drainages, Atlantic non-Coastal Plain, and Atlantic Coastal Plain were evaluated as well as a statewide grouping for fish and benthic data. This extensive dataset provided the opportunity for hypothesis testing and prioritization of flow-ecology relations that have the potential to explain the effect(s) hydrologic alteration has on biological metrics in Virginia.

This dataset provides analysis results for recent status of and trends in 44 fish and 99 macroinvertebrate assemblages in the Chesapeake Bay watershed. For both biological datasets a multi-metric index, metric of assemblage sensitivity, functional feeding group metric and habitat preference metric was selected for analysis. Sites used to calculate trends required a minimum of 7 years of data. Status was calculated as a three-year average by averaging metric values for the most recent three years of data at each site and trends were calculated using generalized additive models (GAM) in the R package 'mgcv' for the full window of sample years at each site. Detailed data preparation information, analytical methods, and results are presented and discussed in the associated Scientific Investigative Report (https://doi.org/10.3133/sir20255072).

We used 14 years (10-01-1999 to 09-30-2014) of biological data (benthic macroinvertebrate and stream fish community data and complementary biological metrics) that was collected from Alabama streams confined to the Mobile River basin and other Gulf Coast drainages in conjunction with land use data and process-based model hydrological (i.e., Precipitation-Runoff Modeling System; PRMS), and water quality (i.e., Spatially Referenced Regression On Watershed Attributes, SPARROW) outputs to explore the effects of land use-driven high and low flow conditions on resource limited taxa abundances and three biological metrics across two landscapes. A landscape consisted of all level III ecoregions above or below the geological feature referred to as the fall line across Alabama. We created two taxa-specific datasets for each landscape by connecting taxa-specific biological samples and the corresponding biological metrics to NHDPlus COMIDs and then used this spatial reference to relate these data to PRMS stream segments. This process enabled us to compile hydrologic metrics, long-term estimates of urban and agricultural land use, and water quality gradients for each biological sample. Biological datasets were compiled from samples collected by two Alabama state agencies: the Alabama Department of Environmental Management (ADEM) and the Geological Survey of Alabama (GSA). ADEM collected all benthic macroinvertebrate samples, while GSA collected all stream fish samples. All ADEM's benthic macroinvertebrate samples included raw community data, along with biological condition gradient (BCG) and Ephemeroptera, Plecoptera, and Trichoptera scores. GSA's stream fish samples included the raw community data and fish index of biological integrity scores. For all biological samples, NHDPlus COMIDs, and PRMS segments we also integrated the following attributes into each of our four datasets; for each biological sample we included its collection date, site ID, and geographic coordinates (decimal degrees); for each COMID, we included its cumulative drainage area (square kilometers) and slope (percentage) and identified the segment’s relevant level III ecoregion; and for each PRMS segment we included its cumulative drainage area (square kilometers). For each of the four datasets, we used PRMS predicted daily streamflow data to calculate 171 biologically relevant hydrologic metrics for each PRMS stream segment and used SPARROW long-term annual, COMID-specific estimates of total nitrogen, total phosphorus, and suspended sediment to generate standardized water quality gradients by incorporating these variables into principal component analyses. We then used annual land cover datasets (2001, 2004, 2005, 2006, 2008, 2011, 2012, 2013, and 2014) to calculate long-term averages of the percentages of urban and agricultural land use associated with each PRMS stream segment, and then estimates were used to identify high and low flow metrics that were only significantly correlated with either land use type. We then integrated the standardized water quality gradients, subsets of hydrologic metrics, and taxa-specific community data into community models to identify resource-limited taxa that were responsive to land use- driven flow conditions. Finally, we used these resource-limited taxa, the three biological metrics, standardized water quality gradients and subsets of hydrologic metrics to evaluate the impact of land use-driven flow conditions on aquatic communities native to Alabama streams. References: Olden, J. D., & Poff, N. L. (2003). Redundancy and the choice of hydrologic indices for characterizing streamflow regimes. River research and applications, 19(2), 101-121. LaFontaine, J.H., Hay, L.E., and Farmer, W.H., 2019, Model Input and Output for Hydrologic Simulations of the Southeastern United States for Historical and Future Conditions: U.S. Geological Survey data release, https://doi.org/10.5066/F74X56PH. Roland, V.L., II, and Hoos, A.B., 2020, SPARROW model

We used 14 years (10-01-1999 to 09-30-2014) of biological data (benthic macroinvertebrate and stream fish community data and complementary biological metrics) that was collected from Alabama streams confined to the Mobile River basin and other Gulf Coast drainages in conjunction with land use data and process-based model hydrological (i.e., Precipitation-Runoff Modeling System; PRMS), and water quality (i.e., Spatially Referenced Regression On Watershed Attributes, SPARROW) outputs to explore the effects of land use-driven high and low flow conditions on resource limited taxa abundances and three biological metrics across two landscapes. A landscape consisted of all level III ecoregions above or below the geological feature referred to as the fall line across Alabama. We created two taxa-specific datasets for each landscape by connecting taxa-specific biological samples and the corresponding biological metrics to NHDPlus COMIDs and then used this spatial reference to relate these data to PRMS stream segments. This process enabled us to compile hydrologic metrics, long-term estimates of urban and agricultural land use, and water quality gradients for each biological sample. Biological datasets were compiled from samples collected by two Alabama state agencies: the Alabama Department of Environmental Management (ADEM) and the Geological Survey of Alabama (GSA). ADEM collected all benthic macroinvertebrate samples, while GSA collected all stream fish samples. All ADEM's benthic macroinvertebrate samples included raw community data, along with biological condition gradient (BCG) and Ephemeroptera, Plecoptera, and Trichoptera scores. GSA's stream fish samples included the raw community data and fish index of biological integrity scores. For all biological samples, NHDPlus COMIDs, and PRMS segments we also integrated the following attributes into each of our four datasets; for each biological sample we included its collection date, site ID, and geographic coordinates (decimal degrees); for each COMID, we included its cumulative drainage area (square kilometers) and slope (percentage) and identified the segment’s relevant level III ecoregion; and for each PRMS segment we included its cumulative drainage area (square kilometers). For each of the four datasets, we used PRMS predicted daily streamflow data to calculate 171 biologically relevant hydrologic metrics for each PRMS stream segment and used SPARROW long-term annual, COMID-specific estimates of total nitrogen, total phosphorus, and suspended sediment to generate standardized water quality gradients by incorporating these variables into principal component analyses. We then used annual land cover datasets (2001, 2004, 2005, 2006, 2008, 2011, 2012, 2013, and 2014) to calculate long-term averages of the percentages of urban and agricultural land use associated with each PRMS stream segment, and then estimates were used to identify high and low flow metrics that were only significantly correlated with either land use type. We then integrated the standardized water quality gradients, subsets of hydrologic metrics, and taxa-specific community data into community models to identify resource-limited taxa that were responsive to land use- driven flow conditions. Finally, we used these resource-limited taxa, the three biological metrics, standardized water quality gradients and subsets of hydrologic metrics to evaluate the impact of land use-driven flow conditions on aquatic communities native to Alabama streams. References: Olden, J. D., & Poff, N. L. (2003). Redundancy and the choice of hydrologic indices for characterizing streamflow regimes. River research and applications, 19(2), 101-121. LaFontaine, J.H., Hay, L.E., and Farmer, W.H., 2019, Model Input and Output for Hydrologic Simulations of the Southeastern United States for Historical and Future Conditions: U.S. Geological Survey data release, https://doi.org/10.5066/F74X56PH. Roland, V.L., II, and Hoos, A.B., 2020, SPARROW model

The United States Geological Survey Virginia and West Virginia Water Science Center (USGS VA-WV-WSC) and Fairfax County assembled this data release in support of ongoing USGS VA-WV-WSC monitoring and evaluations of stream conditions overtime of two previously restored, urban-suburban streams in Reston, Virginia – Snakeden Branch and The Glade. The aquatic benthic macroinvertebrate, fish, and habitat sampling and surveying were conducted on the same eight, 100-meter stream reaches (four reaches in Snakeden Branch and four reaches in The Glade) by the USGS VA-WV-WSC. Aquatic benthic macroinvertebrate sampling and physical habitat surveys were conducted in both Spring and Fall of 2021 and a fish survey was conducted in the Summer 2021. Data provided are of five general types: 1. Site locations and characteristics for each of the eight sampling and surveying sites within the two monitored streams; 2. Benthic macroinvertebrate identifications and analytical laboratory results; 3. Fairfax County benthic macroinvertebrate Index of Biotic Integrity (IBI) scores and individual metric results; 4. Fish assemblages, and; 5. Physical habitat measurements. The metadata file “Metadata_for_Reston_Ecological_Data.xml” contains important information pertaining to the attributes of each entity of data, field and laboratory methods, and caveats associated with the Fall benthic macroinvertebrate IBI and metric scores. The "README.txt" file contains a description of each file contained in this data release. This database contains the aquatic benthic macroinvertebrate taxonomic identification and abundance data derived from samples collected at each of the eight total reaches within Snakeden Branch and The Glade in Fall and Spring of calendar year 2021. Samples were collected by the USGS VA-WV-WSC using the Fairfax County standard operating procedures (FCSOP) and specimen identification and abundance calculations were performed by a third-party laboratory. Fairfax County benthic macroinvertebrate IBI scores and individual metrics were calculated by Fairfax County following FCSOP. It is important to note for this data release that the IBI scores presented for Fall samples have caveats associated with them and the ratings (e.g. Excellent, Good, Fair, etc.) for the Fall samples have been intentionally excluded. Please read the methods section of the “Metadata_for_Reston_Ecological_Data.xml” file carefully for further explanation. This data release also contains the fish assemblages data, collected during the Summer of 2021, from the eight total reaches in Snakeden Branch and The Glade. Electrofishing surveys were conducted following FCSOP by the USGS VA-WV-WSC to obtain these results. Finally, this data release contains the physical habitat data surveyed in both Fall and Spring of 2021. Multiple habitat metrics were measured throughout each of the eight total reaches on Snakeden Branch and The Glade.

The United States Geological Survey Virginia and West Virginia Water Science Center (USGS VA-WV-WSC) and Fairfax County assembled this data release in support of ongoing USGS VA-WV-WSC monitoring and evaluations of stream conditions overtime of two previously restored, urban-suburban streams in Reston, Virginia – Snakeden Branch and The Glade. The aquatic benthic macroinvertebrate, fish, and habitat sampling and surveying were conducted on the same eight, 100-meter stream reaches (four reaches in Snakeden Branch and four reaches in The Glade) by the USGS VA-WV-WSC. Aquatic benthic macroinvertebrate sampling and physical habitat surveys were conducted in both Spring and Fall of 2021 and a fish survey was conducted in the Summer 2021. Data provided are of five general types: 1. Site locations and characteristics for each of the eight sampling and surveying sites within the two monitored streams; 2. Benthic macroinvertebrate identifications and analytical laboratory results; 3. Fairfax County benthic macroinvertebrate Index of Biotic Integrity (IBI) scores and individual metric results; 4. Fish assemblages, and; 5. Physical habitat measurements. The metadata file “Metadata_for_Reston_Ecological_Data.xml” contains important information pertaining to the attributes of each entity of data, field and laboratory methods, and caveats associated with the Fall benthic macroinvertebrate IBI and metric scores. The "README.txt" file contains a description of each file contained in this data release. This database contains the aquatic benthic macroinvertebrate taxonomic identification and abundance data derived from samples collected at each of the eight total reaches within Snakeden Branch and The Glade in Fall and Spring of calendar year 2021. Samples were collected by the USGS VA-WV-WSC using the Fairfax County standard operating procedures (FCSOP) and specimen identification and abundance calculations were performed by a third-party laboratory. Fairfax County benthic macroinvertebrate IBI scores and individual metrics were calculated by Fairfax County following FCSOP. It is important to note for this data release that the IBI scores presented for Fall samples have caveats associated with them and the ratings (e.g. Excellent, Good, Fair, etc.) for the Fall samples have been intentionally excluded. Please read the methods section of the “Metadata_for_Reston_Ecological_Data.xml” file carefully for further explanation. This data release also contains the fish assemblages data, collected during the Summer of 2021, from the eight total reaches in Snakeden Branch and The Glade. Electrofishing surveys were conducted following FCSOP by the USGS VA-WV-WSC to obtain these results. Finally, this data release contains the physical habitat data surveyed in both Fall and Spring of 2021. Multiple habitat metrics were measured throughout each of the eight total reaches on Snakeden Branch and The Glade.

This data release links fish survey data from a suite of programs in the Chesapeake Bay watershed as well the benthic macroinvertebrate sites included in the Chesapeake Bay Basin-wide Index of Biotic Integrity (Chessie BIBI) developed by the Interstate Commission on the Potomac River Basin (ICPRB) and available from the Chesapeake Bay Program (https://datahub.chesapeakebay.net/LivingResources). The data set contains site name, survey program, coordinates of sample, and ancillary information such as sample date and site location information where available. It also includes the NHDPlus V2.1 unique identifier, COMID, as well as a confidence classification category for each of these assignments based on a set of pre-determined rules. In total there were 15 confidence categories ranging from high confidence to low confidence. We caution the use of sampling points which were given anything other than "high" confidence in their assignment to a given NHD catchment/flowline to avoid spurious/inappropriate attribution of geospatial data to benthic macroinvertebrate and fish data samples represented herein and refer the potential user to the Confidence Dictionary.csv which describes the criteria for each confidence category.

This data release links fish survey data from a suite of programs in the Chesapeake Bay watershed as well the benthic macroinvertebrate sites included in the Chesapeake Bay Basin-wide Index of Biotic Integrity (Chessie BIBI) developed by the Interstate Commission on the Potomac River Basin (ICPRB) and available from the Chesapeake Bay Program (https://datahub.chesapeakebay.net/LivingResources). The data set contains site name, survey program, coordinates of sample, and ancillary information such as sample date and site location information where available. It also includes the NHDPlus V2.1 unique identifier, COMID, as well as a confidence classification category for each of these assignments based on a set of pre-determined rules. In total there were 15 confidence categories ranging from high confidence to low confidence. We caution the use of sampling points which were given anything other than "high" confidence in their assignment to a given NHD catchment/flowline to avoid spurious/inappropriate attribution of geospatial data to benthic macroinvertebrate and fish data samples represented herein and refer the potential user to the Confidence Dictionary.csv which describes the criteria for each confidence category.

This data release links benthic macroinvertebrate sites to both the NHDPlus Version 2 and NHDPlus High Resolution Region 02 networks, hereafter referred to as V2 and HR, using the hydrolink methodology. Linked benthic macroinvertebrate sites are those included in the Chesapeake Bay Basin-wide Index of Biotic Integrity (Chessie BIBI) developed by the Interstate Commission on the Potomac River Basin (ICPRB) and available from the Chesapeake Bay Program (https://datahub.chesapeakebay.net/LivingResources). The data set contains a unique sample identifier created by ICPRB, survey program, coordinates of sample, linked V2 COMID and HR Permanent Identifier, and information regarding uncertainty in the attribution. We strongly caution the use of sampling points with attribution uncertainty to avoid spurious attribution of geospatial data to benthic macroinvertebrate samples.

This data release links benthic macroinvertebrate sites to both the NHDPlus Version 2 and NHDPlus High Resolution Region 02 networks, hereafter referred to as V2 and HR, using the hydrolink methodology. Linked benthic macroinvertebrate sites are those included in the Chesapeake Bay Basin-wide Index of Biotic Integrity (Chessie BIBI) developed by the Interstate Commission on the Potomac River Basin (ICPRB) and available from the Chesapeake Bay Program (https://datahub.chesapeakebay.net/LivingResources). The data set contains a unique sample identifier created by ICPRB, survey program, coordinates of sample, linked V2 COMID and HR Permanent Identifier, and information regarding uncertainty in the attribution. We strongly caution the use of sampling points with attribution uncertainty to avoid spurious attribution of geospatial data to benthic macroinvertebrate samples.