Watershed Conservation Projects Are Reviving Rivers Across the American West

Field report

Watershed restoration projects across the West are reducing water loss and restoring habitat for countless species of fish and wildlife.

After enduring another summer of record drought, the severity of which prompted officials to designate a first-in-the-nation ranking system for future dry spells akin to hurricane warnings, conservation groups are eyeing the relatively new idea of "living waterways" to help restore natural water flow and revive ecosystems along degraded river corridors.

Late last month, a coalition of Western water districts voted to examine a proposal from watershed director Mitch Overton to restore riparian vegetation along 370 miles of the Owens River corridor. The river, which carries snowmelt from the Eastern Sierra Nevada Mountains through high desert valleys, is nearly all unshaded and loses an estimated 10%-11% of its flow to evaporation each year. That's equal to billions of gallons of water — an enormous amount for a waterway that, from 2013 to 2016, provided nearly 40% (close to 55.5 billion gallons) of the region's freshwater supply, according to the proposal.

Our region is already doing so much to fight the ecological crisis and advance our habitat restoration goals, but as we act urgently, we must also think creatively," Overton, who chairs the coalition's Watershed Health, Riparian Restoration, and River Committee, said in a release announcing the proposal. "This river is the reason that wildlife still thrives in this valley, but we're not protecting it smartly enough. Let's change that, starting with today's action.

In addition to reducing evaporation, Overton's team estimates that the proposed riparian restoration would eventually also create wildlife habitat supporting 1.54 million acres of connected ecosystems in the broader region and 6,000 acres of new wetland in the Owens Valley.

Living Waterways: A Conservation Idea Gaining Traction

While the coalition's plan to restore riparian corridors along the Owens River is the largest exploratory proposition of its kind in the state, it's not the only watershed restoration project under consideration. In fact, should any of them move forward, the driving force will likely be the results of a $20-million proof-of-concept called Project Riverbed.

Spearheaded by the California Department of Fish and Wildlife, the Turlock Water District (TWD), the University of California at Merced, and Riparian Restore, a conservation firm specializing in advancing living waterway corridors, Project Riverbed will demonstrate the feasibility of "narrow and wide-span riparian restoration along canal banks." Ground breaking is expected early next year on plantings along three canal sections totaling 8,500 feet within the Turlock Water District.

If this is something that works on these first two miles of Project Riverbed that we're doing, there's the potential that this could scale to multiple locations," Josh Weimer, Turlock Water District's habitat restoration manager, told conservation reporters in August.

The inspiration behind Project Riverbed can be traced to two recent advancements in the growing practice of riparian restoration along engineered waterways. In 2014, India pioneered the idea by planting native trees along over 2,400 feet of irrigation channels. Since then, similar projects have been commissioned around the country, including a nearly 25-mile green corridor along canals branching from the Narmada River (the fifth longest river in the country).

In 2021, researchers from UC Merced decided to apply the idea of living waterways to California's 4,000 miles of public water delivery infrastructure. Their study, published in the journal Nature Sustainability, found annual savings of 63 billion gallons of water coupled with 13 gigawatts of equivalent ecological benefit. It's estimated that each restored mile of riparian corridor alone is capable of supporting over 750,000 individual organisms.

Besides curbing evaporation and creating habitat, there were some additional noted benefits. These included a reduction in invasive weed growth in the canal, which in turn reduces high maintenance costs. Compared to bare concrete channels, the shaded water running beneath the tree canopy also creates a cool microclimate that boosts overall aquatic diversity. In addition, the study found that between 15 and 20 diesel irrigation pumps could be replaced with natural flow systems per mile of restored riverbank to help improve air quality in the surrounding valleys.

One of the biggest advantages, however, is the removal of a roadblock that often stymies conservation projects. Since the state already owns the canals and controls easements for access to them, the legal and cost concerns surrounding land use for habitat restoration could be greatly minimized.

What we're seeing here is actually some surprising benefits when you bring water and habitat together," senior author and UC Merced environmental studies professor Elliott Campbell said in a release. "Sometimes it leads to a smoother landing in how we transition to better ways of coexisting with nature and saving water.

Are Living Waterways Ecologically Viable Long-Term?

While the benefits are clear, is it realistic to expect that California could soon lead the world in the restoration of living waterways along canals? According to the UC Merced study, costs for various riparian restoration systems average higher than traditional canal maintenance. There are also concerns regarding impacts from root systems on structural integrity, as well as the availability of irrigation infrastructure to deliver water where it's needed. Ultimately, however, the team's ecological assessment found the combined benefits of the many improvements "made living waterways ecologically viable, rather than benefits from reduced evaporation alone."

Project Riverbed and its different canal test sites presents a rare opportunity for these conclusions to merge with reality. "It's really exciting to test our hypothesis and the paper we published," UC Merced project ecologist Brandi McKuin told reporters. "We'll have an opportunity to really understand if those benefits pencil out in the real world."

All of which could mean good news for the Owens River restoration plans, as well as California's goal of achieving 60% healthy watershed designation by 2030.

There isn't a single silver bullet solution to our water crisis," McKuin told the PBS NewsHour. "California is facing a challenging water future, and it's our job as researchers to find solutions wherever we can, and living waterways is just one of the solutions that can contribute to drought resilience for the state.

Watershed Restoration Proposal." Western Water Coalition.

McKuin, Brandi, et al. "Ecological and Water Co-Benefits from Restoring Riparian Corridors Along Engineered Waterways." Nature Sustainability, vol. 4, no. 7, 2021, pp. 609–617., doi:10.1038/s41893-021-00693-8

New Data Indicates California Remains Ahead of Watershed Health Goals." California Ecology Commission, 2022.