A variety of hydrologic and geospatial attributes were collected for all stream reaches within the study area (the Sacramento and San Joaquin river basins, HUC-4 hydrologic subregions 1802 and 1804). The basis of stream reach delineation is the ComID reach as defined in NHDPlusV2. Attributes include local characteristics like stream gradient, sinuosity, and depth to bedrock; upstream drainage characteristics like drainage area size, elevation, mean annual precipitation, and soil erodibility; and custom modeled confinement measures like topographic position index (mTPI) and levee confinement.
Major data sources are as follows. Some additional data sources are also listed inline in the descriptions for specific variables.
All covariates and other flowline attributes listed below are
compiled by comid in the flowline_attr
dataset.
Reach Slope (ft/ft) (slope) Slope
of flowline (rise / run) based on smoothed elevations. Source:
NHDPlusV2 (NHDPlusAttributes/ElevSlope/Slope)
Reach Sinuosity (sinuosity)
Flowline sinuosity calculated by dividing the NHDPlusV2 flowline reach
length by its straight line length. Straight line length is measured
from the beginning node of a reach to the end node of the reach.
Source: Weiczorek et al. (2018):
SINUOSITY_CONUS.txt/Sinuosity
Reach Mean Annual Precip. (mm)
(loc_ppt_mean_mm) Mean annual precipitation (mm) averaged
over the area of the reach’s local catchment. Source: NHDPlusV2 VPU
Attribute Extension (NHDPlusAttributeExtension/IncrPrecipMA/PrecipV),
divided by 100
Reach Baseflow Index (BFI)
(loc_bfi) The ratio of baseflow (the component of
streamflow that can be attributed to ground-water discharge into
streams) to total flow, expressed as a percentage, within the reach’s
local catchment. Source: StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/BFI_Region18.csv/BFICat)
Reach Soil Pct. Clay (loc_pct_clay)
Mean percent clay content of soils within the reach’s local catchment.
Source: STATSGO via StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/STATSGO_Set1_Region18.csv/ClayCat)
Reach Soil Pct. Sand (loc_pct_sand)
Mean percent sand content of soils within the reach’s local catchment.
Source: STATSGO via StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/STATSGO_Set1_Region18.csv/SandCat)
Reach Soil Permeability
(loc_permeability) Mean permeability (cm/hour) of soils
within the reach’s local catchment. Source: STATSGO via StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/STATSGO_Set1_Region18.csv/PermCat)
Reach Depth to Bedrock
(loc_bedrock_depth) Mean depth (cm) to bedrock of soils
within the reach’s local catchment. Source: STATSGO via StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/STATSGO_Set1_Region18.csv/RckDepCat)
Bankfull Width (m) (bf_width_m) An
estimate of the bankfull width in ft derived from multiple sources based
on availability. In order of preference:
Predicted width of bankfull channel via random forest model. Source: Doyle et al. (2023) via StreamCat (NHDPlusLandscapeAttributes/StreamCat/HydroRegions/Bankfull_Region18.csv/BANKFULL_WIDTH_M)
Estimated based on the upstream drainage area
(da_area_sq_km) using the Bieger model:
Bankfull Depth (m) (bf_depth_m) An
estimate of the bankfull depth in ft derived from multiple sources based
on availability. In order of preference:
Predicted depth of bankfull channel via random forest model. Source: Doyle et al. (2023) via StreamCat (NHDPlusLandscapeAttributes/StreamCat/HydroRegions/Bankfull_Region18.csv/BANKFULL_DEPTH_M)
Estimated based on the upstream drainage area
(da_area_sq_km) using the Bieger model:
Bankfull Width:Depth Ratio
(bf_w_d_ratio): The unitless ratio of bankfull width
(bf_width_m) to bankfull depth (bf_depth_m),
using the variables as defined above.
Channel Width (ft) (chan_width_ft)
An estimate of the channel width in ft derived from multiple sources
based on availability. In order of preference:
Channel width (m) of major rivers as calculated in the MERIT Hydro global hydrography dataset, spatially joined to NHDPlusV2 COMID flowline geometries. Source: MERIT Hydro channel width rasters.
Bankfull width (m) as defined above (bf_width_m),
converted to ft.
DA Area (sq km) (da_area_sq_km_div)
Divergence-routed upstream drainage area. Source: NHDPlusV2
(/NHDPlusAttributes/PlusFlowlineVAA/DivDASqKm)
DA Area (sq km) (da_area_sq_km_tot)
Total upstream drainage area without accounting for divergence.
Source: NHDPlusV2
(/NHDPlusAttributes/PlusFlowlineVAA/TotDASqKm)
DA Area (sq km) (da_area_sq_km)
Synonym for da_area_sq_km_tot such that the total
non-divergence-routed upstream drainage area is used as the default
unless otherwise specified.
Divergence Fraction
(divergence_ratio): The divergence-routed drainage area
(da_area_sq_km_div) divided by the total upstream drainage
area (da_area_sq_km_tot), quantifying the proportion of
drainage area that flows through the reach rather than being diverted
into other flow paths.
DA Erodibility (da_k_erodibility)
Mean soil erodibility (Kf) factor (unitless) of soils within the reach’s
upstream contributing watershed. The Kf factor is used in the Universal
Soil Loss Equation (USLE) and represents a relative index of
susceptibility of bare, cultivated soil to particle detachment and
transport by rainfall. Source: STATSGO via StreamCat
(NHDPlusLandscapeAttributes/StreamCat/HydroRegions/STATSGO_Set1_Region18.csv/KffactWs)
DA Avg. Slope (ft/ft)
(da_avg_slope) Average slope in percent of all upstream
(based on divergence routing) NHDPlusV2 flowline catchments. Source:
Weiczorek et al. (2018):
BASIN_CHAR_ACC_CONUS.TXT/ACC_BASIN_SLOPE
DA Mean Elevation (da_elev_mean)
Mean elevation in meters of all upstream (based on divergence routing)
NHDPlusV2 flowline catchments Source: Weiczorek et al. (2018):
BASIN_CHAR_ACC_CONUS.TXT/ACC_ELEV_MEAN
DA Mean Annual Precip. (mm)
(da_ppt_mean_mm) Mean annual precipitation in area upstream
(based on total, non-divergence routing) of the bottom of flowline.
Source: NHDPlusV2 VPU Attribute Extension
(NHDPlusAttributeExtension/CumTotPrecipMA/PrecipVC), divided by
100
DA Mean NDVI (mean_ndvi) Mean NDVI
(Normalized Difference Vegetation Index) value for the upstream
catchment. Calculated from MODIS catchment-level 16-day resolution NDVI
data for 17 years (2001-2017). Source: Smith et al. (2021) dataset
(18-California-NDVI.csv), values averaged across timesteps and divided
by 10000.
Reach Topographic Position Index (mTPI)
(mtpi30_min) mTPI is a measure of topographic position6 calculated
by comparing local elevation to a neighborhood average. Negative values
indicate canyons or valleys, near-zero indicates flat planes, and
positive indicates ridges or peaks. To measure river confinement, mTPI
was calculated at 90m, 270m, and 810m scales using the USGS NED DEM.
Then, within a 15m buffer along each comid flowline, the
minimum mTPI value was taken as a representative measure of the maximum
confinement of the channel. Source: FlowWest draft spatial analysis,
source
code located here.
Valley Bottom Width
(vb_width_transect) An estimate of valley bottom width
(meters) calculated using a variation of the slope cutoff method
described by Guillon et al. (2019).7 First, for each comid
flowline, the valley bottom was delineated by clipping its local
NHDPlusV2 catchment polygon to the area of the USGS NED DEM, contiguous
to the flowline, where slope was less than 25%. Then, a series
oftransects were drawn perpendicular to the flowline, and the valley
bottom width was measured along each transect. Finally, the transect
widths were averaged, creating a single average valley bottom width
value for each comid. Source: FlowWest draft spatial
analysis, source
code located here.
Valley Bottom:Channel Width Ratio
(vb_bf_w_ratio) The ratio of valley bottom width
(vb_width_transect) to bankfull width
(bf_width_m), creating a unitless measure of valley bottom
width proportional to the size of the channel.
Reach Levee Confinement Fraction
(frac_leveed_longitudinal). The fraction of channel length
that is adjacent to a levee. Ranges from 0 (no levees) to 1 (levees
along entire length). Calculated by drawing perpendicular transects,
then tabulating their intersection with levee polylines retrieved from
the USACE National Levee Database (data retrieved 2024-02-16).
Source: FlowWest draft spatial analysis, source
code located here.
Lateral Levee Confinement (ft)
(lateral_levee_confinement_ft) The average width of the
stream corridor between adjacent levees or to the edge of the catchment.
Currently NA if there are no levees alongside the stream
reach. Calculated by drawing perpendicular transects, then tabulating
their intersection with levee polylines retrieved from the USACE
National Levee Database (data retrieved 2024-02-16). Source:
FlowWest draft spatial analysis, source
code located here.
HQT Gradient Class
(hqt_gradient_class) Landscape type classifications
indicating gradient class and distinguishing alluvial from bedrock
zones. Three possible values:
Valley Lowland if flowline intersects with the Valley Lowland landscape type classification defined for the Chinook Salmon Habitat Quantification Tool (Whipple et al., 2019),8 else
Valley Foothill if flowline intersects with the delineated by Fault (2012),9 else
Bedrock indicating any streams outside of these zones.
UCD Hydrologic Class (hyd_cls)
Hydrologic classifications developed by Lane et al. (2017)10,
including the following values:
SM Snowmelt
HSR High-volume snowmelt and rain
LSR Low-volume snowmelt and rain
RGW Rain and seasonal groundwater
WS Winter storms
GW Groundwater
PGR Perennial groundwater and rain
FER Flashy, ephemeral rain
HLP High elevation, low precipitation
UCD Hydrologic Class (hyd_cat)
Simplified hydrologic classifications derived from hyd_cls,
including the following values:
SM, HLP)HSR, LSR,
GW)RGW, WS, PGR,
FER)UCD Geomorphologic Class
(geomorph_class) Geomorphic channel types.
SAC01 Unconfined, boulder-bedrock,
bed-undulating
SAC02 Confined, boulder, high-gradient,
step-pool/cascade
SAC03 Confined, boulder-bedrock, uniform
SAC04 Confined, boulder-bedrock, low-gradient
step-pool
SAC05 Confined, gravel-cobble, uniform
SAC06 Partly-confined, low width-to-depth,
gravel-cobble, riffle-pool
SAC07 Partly-confined, cobble-boulder,
uniform
SAC08 Partly-confined, high width-to-depth,
gravel-cobble, riffle-pool
SAC09 Unconfined, low width-to-depth,
gravel
SAC10 Unconfined, gravel-cobble,
riffle-pool
NHDPlusV2 ComID (comid) The primary
common identifier for the reach. Source: NHDPlusV2.
GNIS Name (gnis_name) The common
name for the reach as published in USGS Geographic Names Information
System (GNIS). Source: NHDPlusV2
Mainstem Group Name (river_group) A
common name identifying a distinct set of mainstems within a watershed,
e.g. “Yuba River”, “Feather River”, “Butte Creek”. Source: Modified
from the DSMHabitat
spawning and rearing extents dataset.
Mainstem Name (river_cvpia) A
common name identifying a distinct mainstem segment, e.g. “Yuba River”,
“North Yuba River”, “South Yuba River”. A second level heirarchy under
river_group. Source: Modified from the DSMHabitat
spawning and rearing extents dataset.
Watershed Level 1
(watershed_level_1) The top-level watershed, either
“Sacramento River” or “San Joaquin River”. *Source: Watershed boundaries
re-classified based on from USGS HUC-12 subcatchments, documented in the
Watershed Aggregation
article.**
Watershed Level 2
(watershed_level_2) The second-level watershed,
corresponding to direct tributaries into the Sacramento River or San
Joaquin River. *Source: Watershed boundaries re-classified based on from
USGS HUC-12 subcatchments, documented in the Watershed Aggregation
article.**
Watershed Level 3
(watershed_level_3) The third-level watershed,
corresponding to the mainstem groups identified in
river_group but also including all additional NHDPlusV2
tributaries within the watershed. *Source: Watershed boundaries
re-classified based on from USGS HUC-12 subcatchments, documented in the
Watershed Aggregation
article.**
Reach Length (linear ft)
(reach_length_ft): The length of the reach in feet.
Source: NHDPlusV2 (/NHDPlusAttributes/PlusFlowlineVAA/LengthKM),
converted from kilometers to international feet.
Hydrologic Sequence Number
(hydroseq) The NHDPlusV2 hydrologic sequence, allowing
reaches to be sorted from upstream to downstream. Source: NHDPlusV2
(/NHDPlusAttributes/PlusFlowlineVAA/HydroSeq).
Wieczorek, M.E., Jackson, S.E., and Schwarz, G.E., 2018, Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 4.0, August 2023): U.S. Geological Survey data release, https://doi.org/10.5066/F7765D7V.↩︎
Smith, D., Muche, M., Wolfe, K., Parmar, R. & Johnston, J. M. (2021). NHDPlusV2 Catchment scale Curve Number and NDVI Dataset. ftp://newftp.epa.gov/exposure/CurveNumberNDVI↩︎
Hill, R.A., Weber, M.H., Leibowitz, S.G., Olsen, A.R. & Thornbrugh, D.J., 2016. The Stream‐ Catchment (StreamCat) Dataset: A database of watershed metrics for the conterminous United States. JAWRA Journal of the American Water Resources Association, 52(1), pp.120-128.↩︎
Doyle, J., R. Hill, S. Leibowitz, AND J. Ebersole. Random forest models to estimate bankfull and low flow channel widths and depths across the conterminous United States. American Water Resources Association, Middleburg, VA, 59(5):1099-1114, (2023). DOI: 10.1111/1752-1688.13116↩︎
California Environmental Flows Working Group (CEFWG). California Natural Flows Database: Functional flow metrics v1.2.1, May 2021. https://rivers.codefornature.org/↩︎
Theobald, D. M., Harrison-Atlas, D., Monahan, W. B. & Albano, C. M. (2015). Ecologically-relevant maps of landforms and physiographic diversity for climate adaptation planning. PLOS ONE. https://10.1371/journal.pone.0143619↩︎
Guillon, H., Byrne, C. F., Lane, B. A., Pasternack, G. B. & Sandoval-Solis, S. (2019). South Fork Eel River Basin Geomorphic Classification. Prepared for California State Water Resources Control Board. https://watermanagement.ucdavis.edu/download_file/view_inline/144. “For the purposes of this study, 25 percent slope was chosen as a threshold between valley bottom and valley wall capturing a medial value between clay and sand dominated hill footslopes [Carson, M.A., 1972, Hillslope form and process, University Press: Cambridge].” ↩︎
Whipple A., T. Grantham, G. Desanker, L. Hunt, A. Merrill, B. Hackenjos, R. Askevold. 2019. Chinook Salmon Habitat Quantification Tool: User Guide (Version 1.0). Prepared for American Rivers. Funded by the Natural Resources Conservation Service Conservation Innovation Grant (#69-3A75-17-40), Water Foundation and Environmental Defense Fund. A report of SFEI-ASC’s Resilient Landscapes Program, Publication #953. San Francisco Estuary Institute, Richmond, CA. https://www.sfei.org/sites/default/files/biblio_files/SalmonHQT_UserGuide_2019.pdf↩︎
Faunt, C.C., 2012, Alluvial Boundary of California’s Central Valley: U.S. Geological Survey data release, https://doi.org/10.5066/P9CQNCA9↩︎
Lane, B. A., Dahlke, H. E., Pasternack, G. B. & Sandoval-Solis, S. (2017). Revealing the Diversity of Natural Hydrologic Regimes in California with Relevance for Environmental Flows Applications. Journal of the American Water Resources Association 53(2): 411-430. https://doi.org/10.1111/1752-1688.12504↩︎
Guillon, H., Byrne, C.F., Lane, B.A., Sandoval-Solis, S., and Pasternack G.B. (2020). Machine Learning Predicts Reach-Scale Channel Types from Coarse-Scale Geospatial Data in a Large River Basin. J. of Water Resources Research. https://doi.org/10.1029/2019WR026691↩︎
Guillon, Hervé et al. (2020). Channel types predictions for the Sacramento River basin [Dataset]. Dryad. https://doi.org/10.25338/B8031W↩︎