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ENHDPlus Version 2.1 Allocation and Accumulation of Landscape Variables (PUBLISHED)


These data sets provide summaries of natural and anthropogenic landscape features for NHDPlus Version 2 and their associated catchments within the conterminous USA. The data were linked to four spatial components of NHDPlusV2: individual reach catchments, riparian buffer zones around individual reaches, reach catchments accumulated downstream through the river network, and riparian buffer zones accumulated downstream through the river network. Each data set contains a COMID field which can be linked to NHDPlusV2 using the ComID in the flowline shapefiles or FEATUREID in the catchment shapefiles.

The NHDPlusV2 flowline network serves as the spatial infrastructure for many water-quality modeling efforts included under NAWQA's Cycle 3 status and trend assessments. The NHDPlusV2 flowline network is a publicly available digital geospatial framework (database) that depicts the network of streams and their catchments within the conterminous United States (Moore and Diewald, 2016). The database used to allocate and accumulate landscape metrics is based on a topologically reconditioned version of the NHDPlusV2 hydrography network . This database is used for routing purposes only; no cartographic changes were made to the original NHDPlusV2 in either the flowline or catchment line work.

Accumulation of the information downstream through the river network provides a method for differentiating between local and cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total upstream (see here for details). Both approaches use a modified routing database to navigate the NHDPlus flowline network to accumulate the metrics allocated at the flow line catchment level. (see Schwarz and Wieczorek, 2016). The divergence routing method uses a binary approach. Primary paths are coded as 1 and diversions as 0, an all or nothing approach.  Accumulation is a simple apportionment of the cumulate at a diversion. The second method of accumulation computes what is called a “total” aggregation, representing an aggregation of all values of the variable topologically connected upstream and inclusive of the catchment. This method does not apportion at diversions, but is implemented in such a way that values are never double counted because they appear in a diverted path.


ESRI 2014. ArcGIS Desktop: Release 10.2.2 Redlands, CA: Environmental Systems Research Institute.

Falcone, J.A., Carlisle, D.M., Wolock, D.M., and Meador, M.R., 2010, GAGES: a flowline gage database for evaluating natural and altered flow conditions in the conterminous United States: Ecology, v. 91 no. 2,[variously paged], Data Paper in Ecological Archives E091-045-D1, accessed March 16, 2016, at

Hill, Ryan A., Marc H. Weber, Scott G. Leibowitz, Anthony R. Olsen, and Darren J. Thornbrugh, 2016. The Stream-Catchment (StreamCat) Dataset: A Database of Watershed Metrics for the Conterminous United States. Journal of the American Water Resources Association (JAWRA) 52(1): 120-128. DOI: 10.1111/1752-1688.12372

Moore, Richard B. and Thomas G. Diewald, 2016. The Road to NHDPlus — Advancements in Digital StreamNetworks and Associated Catchments. Journal of the American Water Resources Association (JAWRA) 1-10.DOI: 10.1111/1752-1688.12389

McKay, L., T. Bondelid, T. Diewald, J. Johnston, R. Moore, and A. Rea, 2012. NHDPlus Version 2: User Guide., accessed February 2015.

The accumulation data was generated using SAS software, version 9.4 of the SAS System for X64_&PRO platform. Copyright 2014. SAS Institute Inc. SAS and all other SAS Institute Inc. products or service names are registered trademarks or trademarks of SAS Institute Inc., Cary, N.C., USA.

Access Data

All available data sets are available on Science Base

The master variable list is available here

The table below outlines the structure of the data on Science Base with links to each theme

ThemeDescription of Data sets Available Within Theme
ChemicalVariables such as chemical use on agricultural land or atmospheric deposition.
ClimateVariables such as long term temperature averages or monthly precipitation.
Climate and Water Balance ModelVariables associated with Greg McCabe and Dave Wolock's runoff model, including monthly climate variables from 1945 - 2015.
GeologyVariables such as Hunt, Soller, Bush and Reed, or Olson geology.
Variables such as National Inventory of dams, tile drains and irrigation.
HydrologicVariables such as topographic wetness index (TWI) or base flow index (BFI).
LandscapeVariables such as Cropland Data Layer, NLCD, NWALT and other historic landuse coverages.
Population InfrastructureVariables such as decadal population (1990 - 12010) and housing densities from 1940 - 2010.
RegionsVariables such as Level III EcoRegions and Hydrologic Landscape Regions
SoilsVariables related to soil properties from STATSGO or SSURGO data bases.
Topographic CharacteristicsVariables such as basin elevations and slopes.
  • Data are distributed as comma separated CONUS files (see Science Base for additional details). 

Data sets used by specific projects


  • Draft journal article can be found here.
  • The Details page provides additional detail and important information on how to access and use these data.
  • The Quick Variable spreadsheet provides basic list of variables, their items, units and Science Base links.
  • Information on quality assurance steps can be found in the Quality Assurance page.
  • The HST Python Script page has the latest working versions of the code used to derive these data and a brief description of each script used.
  • Data is published and is tabled here.


Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.  Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein.

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