20220316 16230200 1.0 FALSE Hydro_FlowMet_2040sChgAbs -124.724424 -66.988396 25.124123 49.376613 1 002 Geographic GCS_North_American_1983 Angular Unit: Degree (0.017453) <GeographicCoordinateSystem xsi:type='typens:GeographicCoordinateSystem' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:typens='http://www.esri.com/schemas/ArcGIS/10.7'><WKT>GEOGCS[&quot;GCS_North_American_1983&quot;,DATUM[&quot;D_North_American_1983&quot;,SPHEROID[&quot;GRS_1980&quot;,6378137.0,298.257222101]],PRIMEM[&quot;Greenwich&quot;,0.0],UNIT[&quot;Degree&quot;,0.0174532925199433],AUTHORITY[&quot;EPSG&quot;,4269]]</WKT><XOrigin>-400</XOrigin><YOrigin>-400</YOrigin><XYScale>999999999.99999988</XYScale><ZOrigin>-100000</ZOrigin><ZScale>10000</ZScale><MOrigin>0</MOrigin><MScale>1</MScale><XYTolerance>8.98315284119521e-09</XYTolerance><ZTolerance>0.001</ZTolerance><MTolerance>2</MTolerance><HighPrecision>true</HighPrecision><LeftLongitude>-180</LeftLongitude><WKID>4269</WKID><LatestWKID>4269</LatestWKID></GeographicCoordinateSystem> 20220913 00390200 20220913 00390200 FGDC CSDGM Metadata FGDC 150000000 5000 Nathan Walker USDA Forest Service Office of Sustainability and Climate 20220913 ArcGIS Metadata 1.0 USFS Chief Information Office, Enterprise Data Warehouse Please send an e-mail to the address below. Washington DC 20250 SM.FS.data@usda.gov or nathan.walker1@usda.gov Feature Class Flow Metrics for the Contiguous United States (Absolute Change by Mid-Century) 2026-03-09T17:01:18 USDA Forest Service vector digital data For more methodological details, see: Wenger, S.J., C.H. Luce, A.F. Hamlet, D.J. Isaak, and H.M Neville. 2010. Macroscale hydrologic modeling of ecologically relevant flow metrics. Water Resources Research. 46: W09513. doi:10.1029/2009WR008839. This work was supported by the U.S. Forest Service Landscape Restoration & Ecosystem Services Research staff. We acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups listed in this paper for producing and making available their model output. For CMIP the U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison provides coordinating support and led development of software infrastructure in partnership with the Global Organization for Earth System Science Portals. <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>This file represents modeled streamflow across the contiguous United States, for the absolute change between the historical (1977-2006) and projected future mid-century time period (2030–2059), based on gridded simulations of daily total runoff. The flow regime is of fundamental importance in determining the physical and ecological characteristics of a river or stream, but actual flow measurements are only available for a small minority of stream segments, mostly on large rivers. Flows for all other streams must be extrapolated or modeled. Modeling is also necessary to estimate flow regimes under future climate conditions. We modeled streamflow across the contiguous United States, for the historical period (1977–2006), and two projected future time periods, mid-century (2030–2059), and end-of-century (2070–2099). </SPAN><SPAN><SPAN>These are based on gridded simulations of daily total runoff. These use RCP 8.5 projections of temperature and precipitation, downscaled to a 1/8 degree (~12 km) cell size, which are used as inputs to the Variable Infiltration Capacity (VIC) macroscale hydrologic model. This dataset updates the previous Western U.S. Stream Flow Metric Dataset (Wenger et al., 2010) (a link to the old datasets is available on the project website: https://www.fs.fed.us/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml). It expands the spatial extent of this analysis, uses updated climate scenarios, and includes additional climate metrics. For each stream segment in the National Hydrography Dataset Plus Version 2 (NHDPlusV2) in the contiguous U.S. we calculated hydrographs for the three time periods. From these we calculated summary flow metrics to describe flow regimes for each stream segment and each time period and joined these to the NHD stream segments for visualization and analysis. These results allow scientists and managers to easily compare historical and projected flow patterns, including monthly, seasonal, and annual flow, flood and drought events, and timing of peak and low flows. Note: We recommend that line segments with an upstream area greater than 10,000 km2 be removed from the dataset for consideration of high flow metrics (using the field 'TotDASqKM'), since the downstream routing was simply an accumulation function. This is reasonable for larger watersheds at time scales of months and greater, but would be inaccurate for estimating floods at daily time scales on larger watersheds. Note also that the 10+ year flood models are not appropriate for use in engineering and design applications. Streams without flow metrics (null values) were removed from this dataset to improve display speed; to see all stream lines, use an NHD flowline dataset.</SPAN></SPAN></P></DIV></DIV></DIV> Modeled streamflow across the contiguous United States, for the absolute change between the historical (1977-2006) and projected future mid-century time period (2030–2059), based on gridded simulations of daily total runoff. USDA Forest Service Rocky Mountain Research Station and Office of Sustainability and Climate. For more details about the analysis methods, see: Wenger, S.J., C.H. Luce, A.F. Hamlet, D.J. Isaak, and H.M Neville. 2010. Macroscale hydrologic modeling of ecologically relevant flow metrics. Water Resources Research. 46: W09513. doi:10.1029/2009WR008839. Nathan Walker USDA Forest Service Office of Sustainability and Climate Please send an e-mail to the address below. Washington DC 20250 US SM.FS.data@usda.gov or nathan.walker1@usda.gov Contiguous United States USA future absolute change USDA Forest Service USFS Rocky Mountain Research Station RMRS Office of Sustainability and Climate OSC Enterprise Data Warehouse EDW water hydrology streams stream flow streamflow climate change flood low flow drought baseflow national hydrography dataset NHD variable infiltration capacity VIC USDA Forest Service USFS Rocky Mountain Research Station RMRS Office of Sustainability and Climate OSC Enterprise Data Warehouse EDW Contiguous United States USA inlandWaters environment water hydrology streams stream flow streamflow climate change flood low flow drought baseflow national hydrography dataset NHD variable infiltration capacity VIC future absolute change The U.S. Forest Service makes no warranty, express or implied, nor assumes any liability or responsibility for the accuracy, reliability, completeness, or utility of these geospatial data or for the improper or incorrect use of those data. The data are dynamic and may change over time. The user is responsible for verifying the limitations of the geospatial data and for using the data accordingly. <DIV STYLE="text-align:Left;"><DIV><DIV><P><SPAN>The USDA Forest Service makes no warranty, expressed or implied, including the warranties of merchantability and fitness for a particular purpose, nor assumes any legal liability or responsibility for the accuracy, reliability, completeness or utility of these geospatial data, or for the improper or incorrect use of these geospatial data. These geospatial data and related maps or graphics are not legal documents and are not intended to be used as such. The data and maps may not be used to determine title, ownership, legal descriptions or boundaries, legal jurisdiction, or restrictions that may be in place on either public or private land. Natural hazards may or may not be depicted on the data and maps, and land users should exercise due caution. The data are dynamic and may change over time. The user is responsible to verify the limitations of the geospatial data and to use the data accordingly.</SPAN></P></DIV></DIV></DIV> Version 6.2 (Build 9200) ; Esri ArcGIS 10.7.1.11595 Contiguous United States, absolute change between the historical (1977-2006) and projected future mid-century time period (2030–2059) 1977-10-01 2059-09-30 0.000000 0.000000 -127.842954 -65.416668 23.245031 51.518966 0.000000 0.000000 baseflow national hydrography dataset NHD variable infiltration capacity VIC 1 -124.724424 -66.988396 49.376613 25.124123 The USDA Forest Service makes no warranty, expressed or implied, including the warranties of merchantability and fitness for a particular purpose, nor assumes any legal liability or responsibility for the accuracy, reliability, completeness or utility of these geospatial data, or for the improper or incorrect use of these geospatial data. These geospatial data and related maps or graphics are not legal documents and are not intended to be used as such. The data and maps may not be used to determine title, ownership, legal descriptions or boundaries, legal jurisdiction, or restrictions that may be in place on either public or private land. Natural hazards may or may not be depicted on the data and maps, and land users should exercise due caution. The data are dynamic and may change over time. The user is responsible to verify the limitations of the geospatial data and to use the data accordingly. Gridded input data were visually inspected for completeness and reasonable values for the location. The data were not extensively compared against observational data. Data are complete as of publication. Inaccuracies in the data can stem from several sources: 1) Input meteorological data - We used the VIC dataset from Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections at https://gdo-dcp.ucllnl.org/downscaled_cmip_projections/dcpInterface.html#About. In previous versions of this analysis, predictions were worse for sites with strong groundwater influence, and some sites showed errors that may result from limitations in the forcing climate data. Higher resolution (1/16th degree) modeling provided small improvements over lower resolution (1/8th degree). Despite some limitations, the VIC model appears capable of representing several ecologically relevant hydrologic characteristics in streams. 2) Stream hydrography - The National Hydrography Dataset version 2 is the highest resolution national stream hydrography layer currently available. As technology improves this component will likely become more accurate and increase our ability to represent small scale features and processes. Flow metrics were calculated for National Hydrography Dataset (NHD) version 2 stream segments that had a COMID (unique identifier) in the value added attributes table (VAA). Since not all stream segments in the NHD flowline layer are in VAA, not all stream segments have flow metrics. Headwater catchments with no area in the NHD did not accumulate flow and therefore do not have flow metrics. Secondary divergences do not receive flow from upstream, therefore only secondary divergences with a local catchment area have flow metrics. We recommend that line segments with an upstream area greater than 10,000 km2 be removed from the dataset for consideration of high flow metrics, since the downstream routing was simply an accumulation function. This is reasonable for larger watersheds at time scales of months and greater, but would be inaccurate for estimating floods at daily time scales on larger watersheds. This can be done using the field ‘TotDASqKM.’ Note also that the 10+ year flood models are not appropriate for use in engineering and design applications. Gridded input data were visually inspected for completeness and reasonable values for the location. The data were not extensively compared against observational data. Gridded input data were visually inspected for completeness and reasonable values for the location. The data were not extensively compared against observational data. To calculate flow metrics for each stream segment, we started with gridded estimates of total runoff for the contiguous United States for three time periods: the historical period (1977-2006), mid-century (2030-2059), and end-of-century (2070-2099). We downloaded all of these from the Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections archive (Reclamation, 2014). Total runoff was calculated using the Variable Infiltration Capacity (VIC) hydrologic model, which uses climate and other inputs to simulate land-atmosphere fluxes, water balance, and hydrological processes (Liang et al., 1994). The climate inputs for this were downscaled using the Bias Correction and Spatial Disaggregation method (Wood et al., 2004), producing runoff data with output grid cells of 1/8 degree (~12 km) on a side. The projected future climate data use RCP 8.5 (a high emissions scenario—see Schwalm et al. (2020) for discussion of this choice). We used five CMIP5 global climate models (GCMs) (Lawrence Livermore National Laboratory, 2021), following the five used by the 2020 Forest Service 2020 RPA Assessment (Joyce & Coulson, 2020): • Least warm: MRI-CGCM3 (Meteorological Research Institute) • Hot: HadGEM2-ES (Met Office Hadley Centre / Instituto Nacional de Pesquisas Espaciais) • Dry: IPSL-CM5A-MR (Institut Pierre-Simon Laplace) • Wet: CNRM-CM5 (Centre National de Recherches Meteorologiques / Centre Europeen de Recherche et Formation Avancees en Calcul Scientifique) • Middle: NorESM1-M (Norwegian Climate Centre) To create stream hydrographs, we took the total runoff for each grid cell, and used this to calculate the total flow in each of the NHDPlusV2 catchments intersecting that cell (U.S. Geological Survey et al., 2012). We then applied these values to the stream segments associated with each catchment, applying a unit hydrograph to simulate the distribution of lag times required for runoff to work its way into the stream and then accumulated these flows downstream (Wenger et al., 2010); see Figure 2 for a visualization of this. These calculations resulted in three long-term time series of daily stream flow for each stream segment: one for the historical period, one for the middle of the 21st century, and one for the end of the century. For each stream segment and time period, we calculated the 23 flow metrics described below. We then averaged the results of the five models listed above to produce an ensemble projection; individual model results are available upon request. We removed stream segments without values for these flow metrics, as well as coastal line segments; versions of the streamflow metric datasets including all NHD segments are also available upon request. For project details, a user guide, and maps, see: http://www.fs.fed.us/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml This differs from previous versions of the flow metrics dataset in that: a) It covers the entire contiguous United States, rather than just the western states. b) This uses updated input data, with newer climate scenarios and models (CMIP5/RCP 8.5 instead of CMIP3/A1B). c) There are a variety of new flow metrics included in this version. d) In this version, flow metrics were calculated for each GCM and then these outputs were averaged. In the previous version, the gridded runoff data from 10 different GCMs were averaged together and then this average was used as the input for the flow metrics calculation. The reason for this change is that in previous versions of the models, future projections involved perturbing the historical time series: all models used the same historical time series, with flood events on the same days, just differences in their magnitudes, so all could be averaged together. In the new models, the data were modeled stochastically, not by perturbing the historical time series, so averaging the gridded output from the different models would have the effect of smoothing out the hydrographs, muting the magnitude of flood events. Calculating the flow metrics for each model separately and then averaging the results at the end resolves this issue. e) In the original version of the data, datasets were served as .dbf tables, rather than as geospatial data. 2026-03-09 2635472 dataset EPSG 6.12(3.0.1) Simple FALSE 2635472 TRUE FALSE Hydro_FlowMet_2040sChgAbs Feature Class 2635472 A collection of geographic features with the same geometry type (such as point, line, or polygon), the same attributes, and the same spatial reference. Esri GIS Dictionary OBJECTID OBJECTID OID 4 10 0 Internal feature number. Esri Sequential unique whole numbers that are automatically generated. COMID COMID String 255 0 0 Common identifier of the NHD feature NHD Data Dictionary Common identifier of the NHD feature GNIS_NAME GNIS_Name String 255 0 0 Feature name from the Geographic Names Information System NHD Data Dictionary >Feature name from the Geographic Names Information System LENGTHKM LengthKM Double 8 38 8 Feature length in kilometers NHD Data Dictionary Feature length in kilometers FTYPE FType Integer 4 10 0 NHD feature type (334: Connector, 336: Canal/Ditch, 428: Pipeline, 460: Stream/River, 558: Artificial Path, e.g., a line through the center of a lake) NHD Data Dictionary NHD feature type (334: Connector, 336: Canal/Ditch, 428: Pipeline, 460: Stream/River, 558: Artificial Path, e.g., a line through the center of a lake) PU_CODE PU_Code String 255 0 0 The NHD region (2-digit hydrologic unit codes) or a subdivision of regions based on NHDPlus 'production units,' designated by letters appended to the region code, such as '10U' (the upper Missouri River basin); see Figure 1 in user guide (available here: http://www.fs.fed.us/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml). NHD Data Dictionary The NHD region (2-digit hydrologic unit codes) or a subdivision of regions based on NHDPlus 'production units,' designated by letters appended to the region code, such as '10U' (the upper Missouri River basin); see Figure 1 in user guide (available here: http://www.fs.fed.us/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml). TOTDASQKM TotDASqKM Double 8 38 8 The total upstream cumulative drainage area in square kilometers; when using this dataset for analysis, we recommend excluding areas with a cumulative area greater than 10,000 sq km. NHD Data Dictionary The total upstream cumulative drainage area in square kilometers; when using this dataset for analysis, we recommend excluding areas with a cumulative area greater than 10,000 sq km. TIDAL Tidal Double 8 38 8 Indicates whether the stream is tidally influenced NHD Data Dictionary Indicates whether the stream is tidally influenced WBAREATYPE WBAreaType String 255 0 0 Indicates for artificial paths whether the line represents one of the following: 'Area of Complex Channels,' 'Canal/Ditch,' 'Lake/Pond,' 'Reservoir,' 'Stream/River,' or 'Wash.' NHD Data Dictionary Indicates for artificial paths whether the line represents one of the following: 'Area of Complex Channels,' 'Canal/Ditch,' 'Lake/Pond,' 'Reservoir,' 'Stream/River,' or 'Wash.' MA_A2040 MA_a2040 Double 8 38 8 Mean flow for January (units: cubic feet per second); the monthly values can be used to derive seasonal estimates for different definitions of seasons for different purposes USDA Forest Service Mean flow for January (units: cubic feet per second); the monthly values can be used to derive seasonal estimates for different definitions of seasons for different purposes MJAN_A2040 MJan_a2040 Double 8 38 8 Mean flow for January (units: cubic feet per second); the monthly values can be used to derive seasonal estimates for different definitions of seasons for different purposes USDA Forest Service Mean flow for January (units: cubic feet per second); the monthly values can be used to derive seasonal estimates for different definitions of seasons for different purposes MFEB_A2040 MFeb_a2040 Double 8 38 8 Mean flow for February (units: cubic feet per second) USDA Forest Service Mean flow for February (units: cubic feet per second) MMAR_A2040 MMar_a2040 Double 8 38 8 Mean flow for March (units: cubic feet per second) USDA Forest Service Mean flow for March (units: cubic feet per second) MAPR_A2040 MApr_a2040 Double 8 38 8 Mean flow for April (units: cubic feet per second) USDA Forest Service Mean flow for April (units: cubic feet per second) MMAY_A2040 MMay_a2040 Double 8 38 8 Mean flow for May (units: cubic feet per second) USDA Forest Service Mean flow for May (units: cubic feet per second) MJUN_A2040 MJun_a2040 Double 8 38 8 Mean flow for June (units: cubic feet per second) USDA Forest Service Mean flow for June (units: cubic feet per second) MJUL_A2040 MJul_a2040 Double 8 38 8 Mean flow for July (units: cubic feet per second) USDA Forest Service Mean flow for July (units: cubic feet per second) MAUG_A2040 MAug_a2040 Double 8 38 8 Mean flow for August (units: cubic feet per second) USDA Forest Service Mean flow for August (units: cubic feet per second) MSEP_A2040 MSep_a2040 Double 8 38 8 Mean flow for September (units: cubic feet per second) USDA Forest Service Mean flow for September (units: cubic feet per second) MOCT_A2040 MOct_a2040 Double 8 38 8 Mean flow for October (units: cubic feet per second) USDA Forest Service Mean flow for October (units: cubic feet per second) MNOV_A2040 MNov_a2040 Double 8 38 8 Mean flow for November (units: cubic feet per second) USDA Forest Service Mean flow for November (units: cubic feet per second) MDEC_A2040 MDec_a2040 Double 8 38 8 Mean flow for December (units: cubic feet per second) USDA Forest Service Mean flow for December (units: cubic feet per second) MDJF_A2040 MDJF_a2040 Double 8 38 8 Mean flow for winter (December/January/February) (units: cubic feet per second) USDA Forest Service Mean flow for winter (December/January/February) (units: cubic feet per second) MMAM_A2040 MMAM_a2040 Double 8 38 8 Mean flow for spring (March/April/May) (units: cubic feet per second) USDA Forest Service Mean flow for spring (March/April/May) (units: cubic feet per second) MJJA_A2040 MJJA_a2040 Double 8 38 8 Mean flow for summer (June/July/August) (units: cubic feet per second) USDA Forest Service Mean flow for summer (June/July/August) (units: cubic feet per second) MSON_A2040 MSON_a2040 Double 8 38 8 Mean flow for fall (September/October/November) (units: cubic feet per second) USDA Forest Service Mean flow for fall (September/October/November) (units: cubic feet per second) HIQ1_5_A2040 HiQ1_5_a2040 Double 8 38 8 The 1.5-year flood is calculated by first finding the greatest daily flow from each year. The 33rd percentile of the annual maximum series defines the flow that occurs every 1.5 years, on average (units: cubic feet per second). USDA Forest Service The 1.5-year flood is calculated by first finding the greatest daily flow from each year. The 33rd percentile of the annual maximum series defines the flow that occurs every 1.5 years, on average (units: cubic feet per second). HIQ10_A2040 HiQ10_a2040 Double 8 38 8 The 10-year flood (90th percentile of the annual maximum series) (units: cubic feet per second) USDA Forest Service The 10-year flood (90th percentile of the annual maximum series) (units: cubic feet per second) HIQ25_A2040 HiQ25_a2040 Double 8 38 8 The 25-year flood (96th percentile of the annual maximum series) (units: cubic feet per second). USDA Forest Service The 25-year flood (96th percentile of the annual maximum series) (units: cubic feet per second). LO7Q1_A2040 Lo7Q1_a2040 Double 8 38 8 Average lowest 7-day flow during the year, with ‘year’ defined either as January–December or June–May, whichever has a lower standard deviation in the date of the low-flow week. This was done so that, for example, in areas with winter droughts, a December to January drought would not be split up by the start of a new year (units: cubic feet per second). USDA Forest Service Average lowest 7-day flow during the year, with ‘year’ defined either as January–December or June–May, whichever has a lower standard deviation in the date of the low-flow week. This was done so that, for example, in areas with winter droughts, a December to January drought would not be split up by the start of a new year (units: cubic feet per second). LO7Q10_A2040 Lo7Q10_a2040 Double 8 38 8 Average lowest 7-day flow during a decade (calculated as the 10th percentile of the annual minimum weekly flows [Lo7Q1]) (units: cubic feet per second). USDA Forest Service Average lowest 7-day flow during a decade (calculated as the 10th percentile of the annual minimum weekly flows [Lo7Q1]) (units: cubic feet per second). BFI_A2040 BFI_a2040 Double 8 38 8 Mean flow for August (units: cubic feet per second) USDA Forest Service Mean flow for August (units: cubic feet per second) LO7Q1DT_A2040 Lo7Q1Dt_a2040 Double 8 38 8 Average date of center of lowest 7-day flow, calculated using either January–December or June–May, whichever has a lower standard deviation in the date of the low-flow week; done to prevent erroneous results when the drought season crosses the break between years (e.g., drought on day 365 of the first year and day 1 of the second year: average day number = 183) (units: calendar date.) USDA Forest Service Average date of center of lowest 7-day flow, calculated using either January–December or June–May, whichever has a lower standard deviation in the date of the low-flow week; done to prevent erroneous results when the drought season crosses the break between years (e.g., drought on day 365 of the first year and day 1 of the second year: average day number = 183) (units: calendar date.) CFM_A2040 CFM_a2040 Double 8 38 8 Center of flow mass/center of timing is calculated using a weighted mean: CFM = ((flow_1*1) +(flow_2*2) + […] + (flow_365*365))/(flow_1 + flow_2 + […] + flow_365) where flow_i is the flow volume on day i of the water year (units: day number of water year [October to September]). USDA Forest Service Center of flow mass/center of timing is calculated using a weighted mean: CFM = ((flow_1*1) +(flow_2*2) + […] + (flow_365*365))/(flow_1 + flow_2 + […] + flow_365) where flow_i is the flow volume on day i of the water year (units: day number of water year [October to September]). W95_A2040 W95_a2040 Double 8 38 8 The average number of daily flows between December 1 and March 31 which exceed the 95th percentile of daily flows across the entire year (units: count) USDA Forest Service The average number of daily flows between December 1 and March 31 which exceed the 95th percentile of daily flows across the entire year (units: count) SHAPE SHAPE Geometry 4 0 0 Feature geometry. Esri Coordinates defining the features. SHAPE.LEN SHAPE.LEN Double 0 0 0