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Predicted Background Conductivity Data

Metadata Updated: March 21, 2021

This "Predicted Background Conductivity" view consists of a shapefile derived from National Hydrography Dataset Plus Version 2.0 which displays modeled natural background conductivity for the continental United States. The displayed information is based on specific conductivity predictions for stream segments in the contiguous United States from the Natural Background Specific Conductivity (NBSC) model. The NBSC model was developed using a random forest modeling approach and enables comparison with measured in-stream conductivity. Geology, soil, vegetation, climate and other empirically measured data were used as inputs. The NBSC model was designed for streams with natural background SC < 2000 µS/cm. Above this level (typical for freshwater), NBSC model estimates may be less reliable. Data for some parameters that affect background SC were not readily available and were therefore not included in the model. These include freshwater and marine interfaces, natural mineral springs, salt deposits which may affect groundwater and streams, and other natural sources of salts. In such areas, the model is likely to underestimate SC. Local knowledge is often necessary to assess differences between predicted and measured background SC. More information about the model and datasets can be found at Freshwater Explorer Story Metadata. The calculated predicted background conductivity for individual stream segments in the contiguous U.S.A. and metadata are accessible from the ArcGIS platform on Predicted Background Conductivity Data. Data is available as table (from Data) or in by pointing and clicking on a stream segment (from Visualization) ( This data set is used in the Freshwater Explorer Beta 0.1 which on Jan. 2020 is password protected but can be obtained by requesting access from and then using the link:

This dataset is associated with the following publication: Olson, J., and S. Cormier. Modeling spatial and temporal variation in natural background specific conductivity. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 53(8): 4316-4325, (2019).

Access & Use Information

Public: This dataset is intended for public access and use. License: See this page for license information.

Downloads & Resources



Metadata Created Date March 21, 2021
Metadata Updated Date March 21, 2021

Metadata Source

Harvested from EPA ScienceHub

Additional Metadata

Resource Type Dataset
Metadata Created Date March 21, 2021
Metadata Updated Date March 21, 2021
Publisher U.S. EPA Office of Research and Development (ORD)
Data Last Modified 2020-01-01
Public Access Level public
Bureau Code 020:00
Schema Version
Harvest Object Id fe9e0463-3745-49cd-bd6c-7fe8fb372049
Harvest Source Id 04b59eaf-ae53-4066-93db-80f2ed0df446
Harvest Source Title EPA ScienceHub
Program Code 020:096
Publisher Hierarchy U.S. Government > U.S. Environmental Protection Agency > U.S. EPA Office of Research and Development (ORD)
Related Documents
Source Datajson Identifier True
Source Hash c6f9cf3315f9498d3f74826f6ec83398a2030d8c
Source Schema Version 1.1

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