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Open Access Publications from the University of California

Protecting and Enhancing River and Stream Continuity

  • Author(s): Jackson, Scott D.
  • Bowden, Alison
  • Graber, Brian
  • et al.

As long linear ecosystems, rivers and streams are particularly vulnerable to fragmentation. There is growing concern about the role of road crossings – and especially culverts – in altering habitats and disrupting river and stream continuity. The River and Stream Continuity Project began in the year 2000 with a startup grant from the Massachusetts Watershed Initiative. The University of Massachusetts took the lead in convening a group of people from a variety of agencies and organizations who were concerned about the impact of road-stream crossings on fish and other aquatic organism passage. In 2005, three of the organizations/agencies that were key players in initiating and implementing the project joined to create the River and Stream Continuity Partnership. Founding members of the

Partnership include:

• UMass Extension ( University of Massachusetts Amherst)

• Massachusetts Riverways Program (MA Department of Fish and Game) and

• The Nature Conservancy

Members of the Partnership have made a commitment to the ongoing implementation of the River and Stream Continuity Project, including updates and revisions to the MA River and Stream Crossing Standards, coordination and implementation of volunteer assessments, management of the Continuity database, and projects to upgrade or replace substandard crossing structures.

Since its beginning, the River and Stream Continuity Project has:

• Developed “Massachusetts River and Stream Crossing Standards” to facilitate river and stream continuity as well as fish and wildlife passage. These standards are referenced in federal and state regulations and policies affecting road-stream crossings.

• Created a field protocol for volunteer assessment of road-stream crossings, including data forms, instructions, and training materials.

• Developed a system for scoring crossing structures for their effects on river and stream continuity and aquatic organism passage based on volunteer assessments.

• Created an online database for data on road-stream crossings collected by volunteers. All crossings are geo-refer enced and information from the database can be easily used in a GIS to depict the location and score of all as sessed structures in participating states.

• Developed a statewide GIS coverage prioritizing all mapped stream segments in Massachusetts into three catego ries based on information about their importance for fish and wildlife.

• Conducted volunteer assessments of road-stream crossings in Massachusetts, Connecticut, Rhode Island, Vermont and New Hampshire.

• Initiated demonstration projects to mitigate known barriers to aquatic organism passage on high-priority streams.

• Developed workshops, presentations and other educational material on the subject of river and stream continuity and the Massachusetts River and Stream Crossing Standards.

Sedimentation from unpaved roads is a primary threat to water quality in Ozark streams. TNC has partnered with various organizations including the US Forest Service (USFS), the Watershed Conservation Resource Center (WCRC), and others to develop a multi-phased approach to address the impacts of unpaved roads on these priority watersheds.

The first step in the approach utilizes advanced GIS/GPS technologies to develop a detailed vehicle-based road inventory of the target watershed or subwatershed. Sub-meter differential GPS with customized data dictionaries are used to characterize the location and function of sediment-producing and conveying features of the road infrastructure, including the road surface, prism and slope, ditches, bars, lead-offs, culverts, crossings, and outlets. The road inventory yields a comprehensive geodatabase and map series of the mapped features.

A stratified random sample of the inventoried road network is then measured to generate sediment yield predictions on ten percent of the road network. Detailed field measurements are collected with differential GPS and customized data dictionaries. The data are entered into the Water Erosion Prediction Project (WEPP) model, a process-based erosion prediction model developed by multiple federal agencies over the past 20 years. With sediment yields predicted for sample sites, erosion predictions are then extrapolated for the entire study watershed using the road inventory geodatabase.

Once sedimentation yields are predicted for each road segment in the entire study area, priority sub-watersheds are identified in the GIS using watershed sediment accumulation tools. These sub-watersheds with high potential for sediment yield may be compared to species inventory data, stream bank erosion surveys, and other land use information to set priorities for conservation planning and prioritization efforts. Priority infrastructure maintenance improvements are also identified through features that were flagged in the road inventory geodatabase as needing repair or replacement.

Road maintenance workshops are held with USFS engineers, county road crews, and other partners to transfer the inventory information, present the findings of the study and to demonstrate best management practices for road maintenance.

Since 2004, TNC and its partners in the Arkansas have worked in three priority Ozark watersheds to inventory over 600 miles of unpaved roads and 3000 associated point features in an area greater than 900 square miles. The area comprises over thirty 6th level (12-digit) HUCs.

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