Presentation Abstract

Critical watershed assessments allow land managers to create strategic plans and prioritize funding and technical assistance when resources are limited. The Natural Resources Conservation Service (NRCS) National Water Quality Initiative (NWQI) provides a framework for watershed assessment to support long-term, strategic watershed planning and prioritize resources. The Tenmile Watershed in the Nooksack Basin in Whatcom County was selected as a pilot watershed for the NWQI assessment for Washington State in 2017. The primary objective of this assessment was to identify critical source areas (CSAs) within the watershed that were most susceptible to nutrient, sediment and bacteria export based on physical (terrain) features and land use. Secondary objectives were to model the effectiveness of conservation practices within CSAs and create an outreach plan for maximum engagement of landowners in the watershed improvement process. NOAA’s open-source Nonpoint Source Pollution and Erosion Comparison Tool (OpenNSPECT) was used to identify CSAs. Spatial data representing terrain features (soils, elevation and hydrology), precipitation, and land use cover within the watershed were collected, aggregated and input into OpenNSPECT. The model identified CSAs for nitrogen, phosphorus, pathogens, and sediment, as well as a combined ranking of all contaminants for the watershed. OpenNSPECT was then used to model the effects of implementation of different conservation practices on pollutant reduction. In one example, the model showed that implementation of winter cover crops on agricultural fields reduced the export area of nitrogen and phosphorus into the watershed by 92% and 79%, respectively, thus improving water quality in the Tenmile Watershed and Nooksack Basin. This assessment process can be used in any watershed to help understand where CSAs are located and how land conservation practices reduce pollutants, thus helping NRCS and local partners prioritize location and land use type (crop, farm, residential, etc.) for conservation practice implementation, including cost-share and technical assistance.

Session Title

Achieving an Integrated Watershed Approach for Freshwater Ecosystems in the Salish Sea

Keywords

Watershed, Mopel, Nitrogen

Conference Track

SSE4: Ecosystem Management, Policy, and Protection

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE4-148

Start Date

4-4-2018 4:45 PM

End Date

4-4-2018 5:00 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 4th, 4:45 PM Apr 4th, 5:00 PM

Watershed assessment modelling to identify critical sources of pollution and evaluate effectiveness of conservation management practices

Critical watershed assessments allow land managers to create strategic plans and prioritize funding and technical assistance when resources are limited. The Natural Resources Conservation Service (NRCS) National Water Quality Initiative (NWQI) provides a framework for watershed assessment to support long-term, strategic watershed planning and prioritize resources. The Tenmile Watershed in the Nooksack Basin in Whatcom County was selected as a pilot watershed for the NWQI assessment for Washington State in 2017. The primary objective of this assessment was to identify critical source areas (CSAs) within the watershed that were most susceptible to nutrient, sediment and bacteria export based on physical (terrain) features and land use. Secondary objectives were to model the effectiveness of conservation practices within CSAs and create an outreach plan for maximum engagement of landowners in the watershed improvement process. NOAA’s open-source Nonpoint Source Pollution and Erosion Comparison Tool (OpenNSPECT) was used to identify CSAs. Spatial data representing terrain features (soils, elevation and hydrology), precipitation, and land use cover within the watershed were collected, aggregated and input into OpenNSPECT. The model identified CSAs for nitrogen, phosphorus, pathogens, and sediment, as well as a combined ranking of all contaminants for the watershed. OpenNSPECT was then used to model the effects of implementation of different conservation practices on pollutant reduction. In one example, the model showed that implementation of winter cover crops on agricultural fields reduced the export area of nitrogen and phosphorus into the watershed by 92% and 79%, respectively, thus improving water quality in the Tenmile Watershed and Nooksack Basin. This assessment process can be used in any watershed to help understand where CSAs are located and how land conservation practices reduce pollutants, thus helping NRCS and local partners prioritize location and land use type (crop, farm, residential, etc.) for conservation practice implementation, including cost-share and technical assistance.