Contributing Partners:

Use OpenNSPECT, the open-source version of the Nonpoint Source Pollution and Erosion Comparison Tool (more), to investigate potential water quality impacts from development, other land uses, and climate change. OpenNSPECT was designed to be broadly applicable. When applied to coastal and noncoastal areas alike, the tool simulates erosion, pollution, and their accumulation from overland flow.

Training is available for this tool.


  • Provides estimates and maps of surface water runoff volumes, pollutant loads, pollutant concentrations, and total sediment loads
  • Helps users identify areas that might benefit from changes to proposed development strategies
  • Processes digital elevation data quickly and easily
  • Provides a means to analyze "what if" land use change scenarios

Technical Requirements

  • MapWindow GIS v.4.8.8 (open source)

Note: Local administrator permissions are needed to install

Data Requirements

Note: View detailed information about the data requirements and links to common data sources.

Stories from the Field

Prioritizing Wetland Restoration Efforts in Wisconsin
OpenNSPECT helped identify potentially restorable wetlands in an effort to manage and control nonpoint source pollution.

Modeling Sediment Yield in Hawaii
N-SPECT was used to estimate the amount of sediment transported to Pelekane Bay.

Assessing Land-Based Threats to Coral Reef Habitats in Laolao Bay, CNMI
OpenNSPECT and the Habitat Priority Planner were used to assess land based threats and prioritize restoration areas.

Assessing Hydrologic Processes to Mitigate Coral Reef Degradation in Hawaii
C-CAP data were analyzed using the Nonpoint Source Pollution and Erosion Comparison Tool to understand hydrologic processes in the Hanalei Bay watershed.

Integrating Decision Support Tools for Land Use Planning in Coastal Texas
Three decision-support tools were used to demonstrate the innovative application and integration of tools for land-use planning and ecosystem management.

Identifying Areas for Water Quality Improvement Projects in Oahu, Hawaii
The Habitat Priority Planner and N-SPECT were used with lidar and land cover data to identify sites that affect water quality in the Ko’olaupoko region.

Ko‘olaupoko Watershed Restoration Action Strategy
N-SPECT was used to identify nonpoint-source pollution sources as part of this strategy, which provides direction for implementation of best management practices.

Integrating N-SPECT with the Development of a Management Plan in South Carolina
N-SPECT was used to predict water quality impacts to the Kingston Lake Watershed from nonpoint-source pollution and erosion.

Tools for Assessing Impacts on Water Quality in South Carolina
The relationship between land cover and water quality are explored through use of N-SPECT and the Impervious Surface Analysis Tool.

Linking Land Cover to Water Quality in Alabama
N-SPECT was used as part of a three-tier strategy to address nonpoint-source pollution at the Weeks Bay National Research Reserve.

Development of Regional Pollution Export Coefficients
Local export coefficients for the N-SPECT model were tested in the northeastern U.S.

OpenNSPECT Community and User Group

Join the group to stay connected and share information about topics such as applications, software updates, and more.

Recommended Citation

Eslinger, David L., H. Jamieson Carter, Matt Pendleton, Shan Burkhalter, Margaret Allen. 2012. “OpenNSPECT: The Open-source Nonpoint Source Pollution and Erosion Comparison Tool.” NOAA Office for Coastal Management, Charleston, South Carolina. Accessed [Month Year] at

Get It now

MapWindow GIS

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  • Version 4.8.8
  • Release date: August 2013

Previous versions of N-SPECT for ArcGIS are available.

OpenNSPECT for MapWindow GIS

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  • Version 1.2
  • Release date: March 2014
  • Compatible with MapWindow GIS
  • The installation package includes support documentation and test data from Hawaii.
  • Significant changes:
    • OpenNSPECT now runs on MapWindow GIS.
    • The tutorial was updated.
    • Curve number and pollutant coefficient tables were added for U.S. Geological Survey National Land Cover Data.
    • A comparison function was added to evaluate differences in land use scenarios.
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