Like many rivers in the southwestern United States, the Virgin River had been impacted by the continuous spread of invasive tamarisk (Tamarix spp.) along it’s corridor. The thick stands of trees along the river were contributing to a myriad of problems: increased habitat loss for many endangered species, increased wildfire risk, and higher risk of flood damage to neighboring communities. In 2010, a massive flood event resulted in major shifts in vegetation along the river’s corridor, including the removal of large stands of tamarisk in the area. In response, the Bureau of Land Management (BLM), in collaboration with the Lake Mead National Recreation Area (managed by the National Park Service), saw the opportunity to address restoration needs of the river through the preparation of a programmatic plan that could be utilized by both federal land management agencies. The plan was a multi-faceted approach to identify methods for restoring native plant communities, by providing examples of how restoration could be implemented to address a variety of land management issues (i.e. urban projects, wildfire, channel instability, remote areas, etc.).
As part of the plan, the BLM needed to address environmental compliance needs and update GIS data pertinent to the river corridor. The data update included a revision to the vegetation structure data for the river corridor. Based on vegetation classification developed by Younkers and Anderson (1986) for the Colorado River Basin, the updated dataset also looked at vegetative height and cover to determine areas where vegetation treatments would be manageable. To address environmental compliance, a programmatic environmental assessment and biological assessments were also needed. The Programmatic Environmental Assessment for the plan looked at potential impacts to soils, hydrology, vegetation, wildlife, and water resources. Two biological assessments were also prepared: an informal assessment to look at effect to three federally listed fish species and the endangered Mojave desert tortoise, and a formal assessment to look at effects related to three federally listed bird species.
Contributions of Heidi Trathnigg, as an employee of Fred Phillips Consulting
- Organized and managed development of written deliverables for submission to the BLM
- Supervised initial field visits to assess vegetation communities for the GIS analysis and identify potential demonstration sites for the restoration plan.
- Prepared major portions of the Environmental Assessment and Primary author of the Formal Biological Assessment.
- Prepared major portions of the Restoration Plan, including development of the invasive plant management and native plant restoration methods.
- Facilitated meetings with the Interdisciplinary Team (IDT) and consulting agencies to develop scope of the project, identify resources for impact analysis, and identify projects for the cumulative impacts section.
Contributions of Sabrina Kleinman, as an employee of Fred Phillips Consulting
- Updated to the vegetation structure classification GIS data using Supervised Identification Classification of multi-spectral aerial imagery, structure height analysis of LiDAR datasets, and field surveys to accurately match imagery with on-the-ground observations.
- Prepared major portions of the Environmental Assessment, including impact analyses of hydrology, vegetation, soils, areas of critical environmental concern, water resources, and forest resources.
- Prepared site analysis information for potential demonstration restoration sites in the Virgin River, including soil and water assessments for salinity and depth, endangered species habitat assessments, vegetation surveys, and identification of access routes.
- Conducted field meetings with project partners from Clark County, Partners in Conservation, and the BLM to discuss restoration needs in urban and remote project sites.
- Presented restoration plan strategy at the Virgin River Working Group annual meeting in collaboration with the BLM and NPS.
- Conducted field surveys to assess vegetation communities and conduct additional water testing to assess dry season water depth.