Research article published on Merced River restoration co-authored by WRA senior geomorphologist

Merced River in Yosemite National Park (photo credit Virginia Mahacek)

The international journal River Research and Applications recently published an article co-authored by WRA senior geomorphologist Virginia Mahacek. The article, titled “Opportunities and Challenges for Restoration of the Merced River through Yosemite Valley, Yosemite National Park, USA”, is posted in a virtual edition of the journal.

From the abstract: Successful river restoration requires understanding and integration of multiple disciplinary perspectives, including evaluations of past and ongoing watershed processes, local geomorphic response, and impacts unique to human activity. Nowhere is this more apparent than along the Merced River in Yosemite National Park, USA, where both an outstanding natural landscape and the consequences of over a century of human disturbances continue to interact.

Ms. Mahacek served as lead geomorphologist for restoration design and implementation (prior to WRA). The consultant team was led by the Bren School of Environmental Science and Management at the University of California, Santa Barbara and collaborated closely with National Park Service (NPS) staff, supported by project funding from the California Cooperative Extension Services Unit.

The objectives were to realize goals within the Merced River Restoration Plan based on objective analyses and practical applications to resolve conflicts between restoration of ecological function and preservation of historic resources and public access. The design consultants led by Ms. Mahacek helped to liaise with the Principal Investigators and relate their questions and findings to field-based geologic and hydrologic investigations and design analyses. This work produced prioritization and phasing for implementation of restoration elements including riparian zone restoration, overbank and off-channel connections, and renewed in-channel dynamics supporting aquatic habitat.

Before (left) and after (right) photos of restoration along Reach 5 of the Merced River in Yosemite National Park (photo credit: Virginia Mahacek)

Balancing challenges of increased park visitor attendance and natural sediment replenishment, the team was successful in implementing restoration during very constrained construction windows year-over-year to produce consistent momentum. The team supported NPS’ goal to “improve the visitor experience while ensuring that the river and National Park are protected for the benefit and enjoyment of present and future generations.”