Chemical and physical attributes, rates of deposition, erosion, and mineralization of bank and floodplain sediments and soils from five study sites in the Smith Creek watershed between 2012 and 2015.

Floodplain surficial soil samples (10 cm depth) were collected from 12 streams in the urbanized Piedmont region of northern Virginia, representing a chronosequence of time (1-10 yrs) since stream restoration. In addition, 3 unrestored urban streams and 3 low impervious surface cover reference streams were measured. The samples were analyzed for total carbon (TC), total nitrogen (TN) and total phosphorus (TP) storage, whereas carbon mineralization potential and equilibrium phosphorus concentration (EPC0) were measured as metrics of nutrient and carbon loss. Samples also were analyzed for soil moisture, pH, particle size, organic matter content, and degree of phosphorus saturation.

Floodplain surficial soil samples (10 cm depth) were collected from 12 streams in the urbanized Piedmont region of northern Virginia, representing a chronosequence of time (1-10 yrs) since stream restoration. In addition, 3 unrestored urban streams and 3 low impervious surface cover reference streams were measured. The samples were analyzed for total carbon (TC), total nitrogen (TN) and total phosphorus (TP) storage, whereas carbon mineralization potential and equilibrium phosphorus concentration (EPC0) were measured as metrics of nutrient and carbon loss. Samples also were analyzed for soil moisture, pH, particle size, organic matter content, and degree of phosphorus saturation.

Dataset includes site averages of measurements of floodplain and streambank sediment physico-chemistry and long-term (dendrogeomorphic) vertical and lateral geomorphic change, and reach scale floodplain width, streambank height, channel width, and streambed particle size. This information was used to calculate fluxes of sediment, fine sediment, sediment-C, sediment-N, and sediment-P of floodplains and of streambanks at each site. Sixty-eight sites were sampled in the USGS Chesapeake and Delaware Floodplain Network. Sites were chosen to have largely unmodified geomorphology, permission to access, and presence of woody vegetation to enable the dendrogeomorphic technique.

Dataset includes site averages of measurements of floodplain and streambank sediment physico-chemistry and long-term (dendrogeomorphic) vertical and lateral geomorphic change, and reach scale floodplain width, streambank height, channel width, and streambed particle size. This information was used to calculate fluxes of sediment, fine sediment, sediment-C, sediment-N, and sediment-P of floodplains and of streambanks at each site. Sixty-eight sites were sampled in the USGS Chesapeake and Delaware Floodplain Network. Sites were chosen to have largely unmodified geomorphology, permission to access, and presence of woody vegetation to enable the dendrogeomorphic technique.

This data release includes data created, collected, and/or otherwise modified in the process of quantifying a sediment budget for the Smith Creek Watershed near New Market, Virginia, USA. Four raster files are included, namely a modeled index of hydrological connectivity, a raster model of modeled floodplain depositional masses and extent, a raster of modeled delivered upland erosion, and a hydrologically conditioned Digital Elevation Model (DEM). Two vector shapefiles are also included. The first documents the results from the stepwise linear regression models developed to estimate erosion attributed to streambeds, streambanks, and floodplains along stream reaches throughout the watershed. The second documents the same results, now converted to mass rates, for streambeds and streambanks at the sub-watershed level. Floodplain mass results are included in the raster documenting depositional masses and modeled floodplain extent. The Finally, five comma delimited tables are included: three contain field-measured rates of erosion and deposition for streambeds, streambanks, and floodplains for a number of sites throughout the watershed, as well as the independent variables used for model development; a fourth table contains information pertaining to density of source samples collected in the field for the various source types; the final table contains data concerning suspended sediment loads measured at the watershed outlet, in addition to flow type classifications.

This data release includes data created, collected, and/or otherwise modified in the process of quantifying a sediment budget for the Smith Creek Watershed near New Market, Virginia, USA. Four raster files are included, namely a modeled index of hydrological connectivity, a raster model of modeled floodplain depositional masses and extent, a raster of modeled delivered upland erosion, and a hydrologically conditioned Digital Elevation Model (DEM). Two vector shapefiles are also included. The first documents the results from the stepwise linear regression models developed to estimate erosion attributed to streambeds, streambanks, and floodplains along stream reaches throughout the watershed. The second documents the same results, now converted to mass rates, for streambeds and streambanks at the sub-watershed level. Floodplain mass results are included in the raster documenting depositional masses and modeled floodplain extent. The Finally, five comma delimited tables are included: three contain field-measured rates of erosion and deposition for streambeds, streambanks, and floodplains for a number of sites throughout the watershed, as well as the independent variables used for model development; a fourth table contains information pertaining to density of source samples collected in the field for the various source types; the final table contains data concerning suspended sediment loads measured at the watershed outlet, in addition to flow type classifications.

Input and release of phosphate, nitrate, and ammonium measured using stacked ion-exchange resin bags on top of soil in floodplains along Pocomoke River, Maryland, in order to evaluate the effectiveness of floodplain reconnection on water quality functions.

Input and release of phosphate, nitrate, and ammonium measured using stacked ion-exchange resin bags on top of soil in floodplains along Pocomoke River, Maryland, in order to evaluate the effectiveness of floodplain reconnection on water quality functions.

Nitrogen (N), phosphorus (P), and suspended-sediment (SS) loads, in Fairfax County, Virginia streams have been calculated using monitoring data from five intensively monitored watersheds for the period from water year (October - September) 2008-2017. Nutrient and suspended-sediment loads were computed using a surrogate (multiple-linear regression) approach with lab analyzed N, P, and SS samples as the response variable and basic water-quality parameters (e.g. turbidity, specific conductance, pH, water temperature), streamflow, and time and seasonal terms that could be measured continuously as predictor (surrogate) variables. The load results represent the total mass of N, P, and SS that was exported from each of the Fairfax County watersheds. Trends in N, P, SS concentrations, as well as basic water-quality parameters including turbidity, water temperature, dissolved oxygen, specific conductance, and pH have been calculated using both non-flow-normalized and flow-normalized Seasonal Kendall tests at 14 monitoring stations in Fairfax County, Virginia for the period beginning April 2008 and ending March 2018. Flow-normalized trends were used to integrate out the effect of annual streamflow variability on concentration (or unit value). Streamflow is an important driver of water-quality conditions; therefore, several datasets are provided describing a suite of annual streamflow metrics: streamflow volume/yield, flashiness, peak stage, baseflow index, stormflow index, and runoff ratio. Depending on the metric, data are provided from the 5 intensively monitored Fairfax County, VA watersheds, the entire 20-station Fairfax County monitoring network (5 intensively monitored + 15 trend only monitoring stations), and/or 3 reference stations that are part of the USGS Chesapeake Bay Non-Tidal Network (USGS Station IDs 01646000, 01654000, 01658500). Streamflow analyses were conducted on data collected in water years 2008-2017 for all Fairfax County monitoring stations as well as station ID 01658500, 1948-2017 for station ID 01654000, and 1946-2017 for 01646000. Benthic macroinvertebrate data were collected annually (waters years 2008 - 2017) by Fairfax County staff from each of the 20 monitoring stations. These data were used to explore trends in 20 biological metrics; the data used to calculate these trends are provided.