Transforming a river corridor: An ambitious partnership has battled invasive plants along 180 miles of the Dolores, providing job training for young people in the process


The Dolores River below McPhee Dam meanders through a rugged landscape. Over time, invasive plants such as tamarisk and Russian knapweed were choking out native species all along the corridor. Then the Dolores River Restoration Partnership, an alliance of numerous individuals and entities, stepped in. Photo courtesy of Dolores River Restoration Project.

What happens when you dam a river, use the resulting reservoir to irrigate 63,000 acres (sending the water to a different watershed), control downstream flows through human-dictated releases, and then have an extended drought?

The ecosystem changes.

This is what has been going on in the Dolores River corridor below McPhee Reservoir.

Ecosystem change is, of course, a constant and normal part of life on Planet Earth. Generally, earth’s various cycles and systems progress towards long-term stable ecological “climax communities.”

However, stable systems can be interrupted by sudden and drastic environmental changes – whether natural like avalanches, forest fires and droughts; or human-caused – such as clearcuts, dams, and pollution. In times of rapid change, some organisms are favored, while others become at-risk or extinct.

Enter the invasives

On the Lower Dolores River, the rapid changes wrought by the dam helped several non-native plants to push out native species, transforming the corridor. Tamarisk, also called salt cedar (Tamarix spp.), and Russian knapweed (Acriptilon repens), are the two primary invasive plants in the Dolores River riparian zones, but there are others. Those include the Russian olive (Elaeagnus angustifolia L.), Scotch thistle (Onopordum acanthium) and “white top,” or hoary cress (Cardaria draba).

How did tamarisk get into the Dolores River corridor? No one knows exactly, but humans are responsible.

One species of tamarisk, T. pentandra, was in cultivation in the United States in the early 1800s, but by 1880 had escaped into areas of Arizona and Texas. Currently in the U.S. there are several species of tamarisk, but they are rabidly hybridizing and becoming increasingly difficult to tell apart.

Tamarisk, originally from the deserts of Eurasia and Africa, has adapted readily to drier Western waterways. It thrives in salty alkaline soils, with seeds that need to be soaked in order to germinate – making it prolific all over the Southwest in drier riverways subject to seasonal runoff.

Tamarisk can establish monoculture “forests,” which not only crowd out native plants but also, due to their long taproots, suck up water reserves used by native plants. Dense forests block river access, offer generally poor wildlife habitat, tend to increase soil salinity, and present a wildfire hazard.

In 2006, Congress passed the Salt Cedar and Russian Olive Control Demonstration Act, which provides both federal and state support for removal of those two plants. Locally, the Dolores River has benefitted from this law.

Forming a resistance

In 2008, representatives of the Bureau of Land Management, Tamarisk Coalition, and The Nature Conservancy began talking about doing something to fight the transformation of the river corridor into a tangle of non-native species. In 2009, an ambitious private-public effort called the Dolores River Restoration Partnership was formed, with funding from the Walton Foundation and other sources. (Disclosure: Free Press editor Gail Binkly has taken minutes for meetings of DRRP.)

“The partnership wanted to address some of these ecological concerns,” said Rusty Lloyd of the Tamarisk Coalition.

Now, after eight years of work along 180 miles of river corridor in two states, the Dolores River Restoration Partnership, or DRRP, stands as a notable example of how organizations with different goals and different stakeholders can work together for the common good. Since DRRP was established, more than 30 agencies, dozens of private landowners, hundreds of volunteers, and hundreds more youths employed by various conservation corps have worked to not only rid the river corridor of invasive plants but to restore native species.

Young at heart

A critical element to the effort was deciding who would do the on-the-ground work involved in the massive effort of restoring native vegetation along the corridor, much of it remote and accessible only by boat.

DRRP’s leaders began thinking young. They turned to the Southwest Conservation Corps, which became a key partner.

“One of our really big goals was to utilize young people as a resource,” Lloyd said. “We bring youth out to work hard in the outdoors, where they gain skills.” Currently, DRRP has crews from the Southwest, Canyon Country, and Western Colorado Conservation Corps working in the river corridor.

Mike Wight, who was the river-restoration director for the last six years, coordinates the conservation-corps crews. Young adults range in age from 18 to 26. Many are local and may have had difficulty finding other employment opportunities in the area.

They receive training before they set out: Wildland Saw Training, on how to operate chainsaws in wilderness, maintain and repair them (the same training firefighters undergo); and herbicide-applicator training through the State of Colorado, to ensure that herbicides are applied correctly and safely.

Crew members may also learn Wilderness First Aid, since they camp out and work in remote areas. Others specialize in native-plant identification. All trainings add to the skills and experience they will take with them when applying for jobs later on.

Lloyd and Wight both are proud that the DRRP has trained over 350 youths since the partnership began. According to Lloyd, this the “shining spot” of their efforts: “We are using young people as a resource and engaging them so that they become the next generation of land stewards.”

Quite a few of the young adults who have worked with DRRP are just out of college or completing a college internship. They often go on to find permanent employment with the BLM or Forest Service, in land-management positions, forestry or firefighting; or they continue with the conservation corps and AmeriCorps in leadership positions. Some branch out to work in other notfor- profit organizations.

Most “alumni” note that they enjoy living and working outside and hope to find permanent jobs in the field – some return year after year because they enjoy it so much.

Many individuals involved in the projects maintain a lifelong connection and commitment to the river, the land, the region, or the work – which is exactly what DRRP means when they say they are grooming the next generation of land stewards.

At press time, Wight had crews gearing up for a two-month-long summer project beginning in June, in which two-person teams carry out rapid vegetation monitoring to assess the number of invasive vs. non-invasive plants, the canopy cover, and the status of tamarisk beetles at specific sites. In July and August, they form four-person teams that conduct secondary weed and tamarisk re-treatment and maintenance.


The Dolores River Restoration Partnership is moving into a lower-key phase of monitoring,
after eight years of work on invasive-plant removal in the river corridor. Courtesy of DRRP.

In the fall the crews shift to three eight-person teams, one crew from each of the conservation-corps groups. These teams spend 10 to 12 weeks doing what Wight calls the “heavy lifting,” cutting down large tamarisk and making brush piles.

“Our project activities are directed by the BLM,” explained Wight, who said that each of the BLM field offices involved (Tres Rios, Grand Junction, Moab, and Uncompahgre) have ecologists who develop restoration plans according to local ecology and district policies. This means that in some locations brush piles may be burned, while in others they are left for wildlife habitat, or chipped for mulch.

The removal of the invasive plants and reintroduction of native species is a long-term project, including manual and mechanical (with chain saws and excavators) removal of the tamarisks, along with herbicide treatment of rootstocks and knapweed. When larger tamarisk trees are cut, they often regrow from the trunk. To prevent this from happening, crews treat the trunks with Garlon® 4 Ultra specialty herbicide in oil, applied to the base of the trunks in late fall and winter.

Meet the beetles!

Additionally, biological control using tamarisk beetles has been found useful. The tamarisk leaf beetle (Diorhabda spp.) was first released in the West in 2001 after being tested for over 10 years to make sure it would not devour native plants. The beetle and its larvae feed on the leaves of the tamarisk, drying them out and turning them brown or yellow. It can take 5-7 years of beetle infestation to kill a tamarisk tree, but infestation curtails reproductive viability, and can help native plants recover.

The beetles present in the Dolores River corridor were first detected in 2007. Lloyd said they suppress tamarisk seeding but there can be drawbacks. “Since the tamarisks rapidly defoliate [under the beetle attack], bird nests, such as those of the Southwestern willow flycatcher, which is an endangered species, can be exposed.” Some reptiles, including lizards and snakes, are also impacted by a rapid tamarisk die-off.

But Wight said the beetles are generally helpful, because if a tamarisk tree is already compromised due to beetle infestation, it will die when cut, thus eliminating the need to treat with herbicide. “The beetle can get the small seedlings,” he said.

Return of the natives

In addition to removing invasive plants, DRRP replants areas with native species and monitors the results.

“Once you remove the invasives, it opens it up for other invasives to move in, so we promote the growth and establishment of native plants,” Lloyd said.

In October 2016, students from Paradox High School met with Dan Oppenheimer, then the DRRP’s coordinator, at the Bedrock boat ramp, where they monitored over 2,000 native plants that had been planted in an area where tamarisk removal had been completed. The students planted the native grasses Alkali sacaton and sand drop seed, as well as the native shrub three-leaf sumac.

Since the DRRP began working in the Dolores River, crews have removed tamarisk from a 180-mile stretch of the river, beginning below McPhee Dam at Bradfield Bridge and working downriver to Moab, where their current operations are focused.

But even after removing the tamarisk and knapweed, thistle and whitetop, the work is not over. “We have to come back to maintain and monitor, which may take another three to four years,” said Lloyd.

Wight added that the monitoring work is essential – “it gives us a sense of where we’re at in the process.”

This year DRRP will continue their work out of the Moab district, work with private landowners in the watershed, and monitor and maintain what has already been accomplished. The group developed a “transition plan” in 2014, which details how the shift from removal of invasives to maintenance and restoration will take place.

Enter the water!

DRRP works with other organizations, including the grassroots Dolores River Dialogue and The Nature Conservancy, which did some pre- and post monitoring of a recent “flush” of the below-dam corridor. The flush was a 72-hour release of 4000 cubic feet per second from McPhee Reservoir on May 4-6, planned by the Dolores Water Conservancy District. The release was intended to help mimic the natural hydrological cycle of springtime runoff flooding, which is supportive of native plants, since some, like the Fremont cottonwood or coyote willow, need the overbank flooding to reproduce

Both Lloyd and Wight lauded the collaborative efforts involving the Dolores Water Conservancy District and Montezuma Valley Irrigation Company to communicate and control river flows below the dam to correspond to the timing and levels of natural flows, saying it has been a win/win situation this year.

Ecological, agricultural, and recreational needs were juggled, with flows monitored and releases planned to maintain reservoir levels yet allow ecological benefits and recreational access.

“This year we had [below-dam] flows in early April for the first time, which means we’re likely to see more natives come back” as a result of the increased water in the below dam corridor, Wight said.

This year’s bountiful snowpack meant more water could be released downriver, enabling crews from DRRP to get out on the river to monitor in May. One crew spent two weeks on the river from Slickrock to Bedrock, while another raft-supported crew spent four days in the field between Gateway and Dewey.

Although secondary treatment and maintenance activities are not as “sexy” as the initial attack, Wight said they are crucial, since they provide the data tracking results of DRRP’s efforts. There is broad consensus among DRRP’s many partners that, having spent more than $6.5 million on DRRP projects in the past six years, the partnership cannot afford to sit back now and let the corridor slide back to an undesirable state.

Wight believes the money has been well spent, since there is “big evidence” of change up and down the river.


Others agree. The Dolores River Restoration Partnership has received numerous awards and recognition for its efforts. In 2011, the Public Lands Foundation gave DRRP a “Landscape Stewardship Certificate of Appreciation,” for advancing and sustaining communitybased stewardship on public lands administered by the BLM.

In 2014, the Colorado Nonprofit Association awarded DRRP the 2014 Colorado Collaboration Award, a statewide award for an organization that exemplifies collaboration between many different entities. DRRP used the $50,000 prize to support long-term stewardship of the Dolores River.

Most recently, in December 2017, The Nature Conservancy awarded the Southwest Conservation Corps, Western Colorado Conservation Corps, Canyon Country Youth Corps and director Mike Wight the Phil James Conservation Award. This is given to an individual or organization for extraordinary contributions or achievements that further the mission of The Nature Conservancy.

“The Dolores River Restoration Partnership is an example of what can happen when public and private individuals, governments and nonprofits groups come together and carefully craft a measurable vision, tear down boundaries of many kinds, and then put forth a lot of work, sweat, and grit to make it happen,” commented Marsha Porter- Norton, the partnership’s longtime facilitator.

“The results we are creating together are a restored river corridor, lasting positive relationships, and many young people gaining foundational skills that will help them the rest of their lives.”

From July 2017. Read similar stories about .