Wetlands around the world protect communities while helping fight climate change



When the Triple Creek wetland restoration effort began (left, 2016), vertical cut banks of up to 10 feet kept Myers Creek disconnected from its floodplain. After building structures that mimic beavers, the cutbanks are dramatically reduced and the water much closer to the floodplain (right, 2018). Photo courtesy Julie Vanderwal, Okanogan Highlights Alliance.

As the world grapples with climate change, those commemorating World Wetlands Day Feb. 2 are highlighting the importance of restoring, conserving, and wisely using wetlands because they can help reduce floods, relieve droughts, and buffer coastlines from extreme weather.

In the state of Washington, we work every day to protect and manage wetlands. The environmental and economic benefits they provide nature, our communities, and way of life are immeasurable.

More likely than not, there’s a wetland near where you live, work, or play. Our state mandate is to ensure Washington does not lose any more acres of wetland and the functions they provide—as well as restore, enhance, and preserve these important resources.

Wetlands: a natural solution
Wetlands provide important habitat for salmon that Washington’s endangered resident orca whales need to survive. We fund riparian restoration work in agricultural areas to benefit salmon.

Wetlands also help filter and clean our drinking water. They control flooding and erosion while providing habitat for other fish and wildlife species. Washington’s wetlands help maintain a safe, healthy environment and economy.



Wetland connected to Little Spokane River.

In Washington, we recognize the harm climate change can have on wetlands—from sea water intrusion to water chemistry changes to even being the source of greenhouse gases when improperly disturbed.

There are also numerous ways wetlands help us cope with climate change including sequestering or storing:

• Carbon efficiently while emitting little methane.
• Twice as much carbon in coastal wetland soil than in all the world’s tropical forests.
• More carbon than they emit as wetlands mature.
• Large amounts of carbon in tree biomass, especially forested wetlands.
• Up to 700 billion tons of carbon around the world—including 96 million tons of carbon every year.
• Water that is released later in the season to mitigate the effects of drought.

Washington community helping restore degraded wetland system

Many state residents are passionate about protecting existing wetlands while others are getting their hands wet and dirty, working hard to restore wetlands that have been degraded. There’s no better example than the Triple Creek wetland restoration project in north-central Washington.

Located on Myers Creek in Okanogan County near the town of Chesaw, the Triple Creek project is part of a privately-owned forested wetland named after three main creeks: Myers, Bolster, and Thorp.



Triple Creek restoration site in

Okanogan County

Historically, Myers Creek cyclically spilled over its banks and inundated the Triple Creek floodplain, including a series of beaver ponds on the creek. However, the stream lost its connection to the floodplain in the late 1990s after a rain-on-snow event combined with other factors and left an incision trench with left vertical cut banks of up to 10 feet.

The beaver ponds became breached and drained, no longer providing grade control or covering large areas of the floodplain. As the now-drier soils started favoring invasive plant species, a thriving great blue heron rookery was abandoned and the wetland became less able to filter and store water.

Triple Creek land stewards join local, state, and federal partnership



Triple Creek in Okanogan County.

The Triple Creek land stewards, who invested in 500 acres together, were disappointed to see a large part of their thriving wetland dry up. After exploring a variety of restoration options, the group selected the local non-profit entity Okanogan Highlands Alliance (OHA) to lead the restoration effort.

OHA, in partnership with Trout Unlimited, U.S. Fish & Wildlife Service, and the National Oceanic and Atmospheric Administration’s Northwest Fisheries Science Center, worked with the land stewards to find the most cost effective ways to address the wetland degradation. The team seeks to improve hydrologic connectivity between Myers Creek and the adjacent wetland, improve fish and wildlife habitat including re-establishing beaver, and restore native wetland vegetation.

OHA secured community-based, federal and state funding—including funds from the settlement agreement reached between Ecology and the owners of the Buckhorn Mountain gold mine for environmental remediation. In addition, local groups, clubs, students, and community members have so far provided more than 1,400 volunteer hours to help restore the wetland.

Engineered beaver dams helping restore Triple Creek wetland


From left to right: In August 2016, Triple Creek restoration team installs structure mimicking a beaver dam. In May 2017, the red arrow would be underwater as the structure is overtopped. In August 2017, the structure is adaptively managed to extend its functional life. By May 2018, Myers Creek comes close to spilling over its banks onto the floodplain. Photo courtesy Julie Vanderwal, Okanogan Highlands Alliance.

The restoration team is focused on reducing the severe stream channel incision that disconnected Myers Creek from the floodplain. The project design mimics the work of beavers by using lines of wooden posts that are woven with branches to slow and redirect stream flows as needed. The structures help capture sediment to build the streambed back up and raise the water table. They also help make the channel longer while reducing its slope, making the system more stable.

By emulating the effect of beavers to slow stream flows, capture sediment, and connect the water with the land, the project aims to improve water quality and increase water storage capacity. Re-establishing beavers, and the plant life they need, is a key component of mitigating local drought and fire issues—increasing resilience to climate change. Wetlands help store water that becomes available later in the season to support streams and underground sources of water, and to offset the effects of drought.

Triple Creek wetland project achieving success

The first structures were installed in the field season before two years of intense flooding, creating optimal conditions for transforming the site. As Myers Creek interacts with the human-made beaver dams, the team's objectives for the stream are being realized more rapidly than expected. In places, the streambed at the site is more than four feet higher now than when work started in 2016—with a 23 percent increase in the overall channel length of Myers Creek within the project area.


Beaver at the restoration site captured on wildlife camera in fall 2017. Natural beaver activity will be critical to long-term project success.

The team continues to repair and enhance instream structures and is dedicated to establishing a healthy riparian plant community. A diverse and robust buffer zone will not only improve native vegetation but will encourage beavers to recolonize the area, and modify and maintain the site into the future.

Beavers have already shown increased interest in the project site, starting just a few days after construction began in 2016. Beavers even wove a post line themselves in 2017, before the project team could get to it!

By Curt Hart, Ecology, and Julie Vanderwal, Okanogan Highlands Alliance

Triple Creek Project:

Human-built 'beaver dams' restore streams

Myers Creek in April 2015 showing the stream damage. Gray alder dominates the tree canopy and extensive reed canarygrass lays on the ground after spring snowmelt. Photo by Julie Vanderwal.

Beavers are a critical asset in Washington, assuring that healthy riparian zones are maintained, especially in the dry climate east of the Cascades. Beaver dams and ponds support native vegetation and wetlands along streams, trap sediment, recharge groundwater, and improve water quality.

Over the last two centuries, these benefits have been lost in many watersheds, following human development, beaver removal, channel deepening, and other impacts.

In 2015, the Okanogan Highland Alliance (OHA) was awarded a grant to restore a reach of Myers Creek, through Ecology’s Water Quality Financial Assistance Program. In the 1990s, Myers Creek was damaged in a major rain-on-snow event, which caused unusually high stream flows, deepening the creek, leaving vertical cut banks, and draining nearby wetlands.

Where beaver ponds had once provided grade control and covered large areas of the floodplain, the now-drier soils began to favor invasive plant species. The understory is now dominated by reed canarygrass (Phalaris arundinacea) and Canada thistle (Cirsium arvense), further suppressing growth of native sedge and forb species. The only remaining native riparian species still easily found in the project area is gray alder (Alnus incana), with a few isolated willow (Salix spp.) plants.

The biggest challenges at this site were the lack of vegetation needed by beaver for food and dam-building, and a straightened, incised channel that now flowed with too much force in the spring to allow beaver dams to take hold.

Engineered beaver dams a solution

OHA, in partnership with the US Fish and Wildlife Service and Trout Unlimited, needed to find a cost effective tool and strategy that would jumpstart ecological recovery at this site and restore it to a condition where beaver could recolonize and maintain riparian function again. That tool was Beaver Dam Analogues, also called BDAs.

Developed by Michael Pollock (NOAA) and colleagues, BDAs offer a low-cost, simple, and easily scalable technique for mimicking beaver dams. They reduce stream velocity, induce lateral channel migration, and cause rapid aggradation of the streambed, which reconnects the floodplain so it can once again support riparian vegetation.

The human-built beaver dams are constructed by driving 3 to 6 inch diameter posts into the stream substrate. Then a hand-woven matrix of various tree species, like dogwood and Douglas-fir, is interlaced between posts to provide the resistance to retain water and trap sediment.


Installation of a manmade beaver dam on Myers Creek in August 2017.

Previous year’s BDA is seen in foreground. Photo by Julie Vanderwal.

BDAs can be constructed as either channel spanning or deflector dams. Channel spanning dams slow the water down and capture it, trapping sediment and raising the streambed (aggradation). Deflector dams leave an aperture for the water to flow around, recruiting sediment from the banks for downstream capture and increasing channel sinuosity.

However, unlike natural beaver dams, the analogue dams must be maintained if they are to continue functioning year after year. This maintenance is needed until vegetation starts to return (or planted vegetation becomes established) and the site can provide enough food and dam material to entice beaver back to the system to take over maintenance of the site.

After extensive planning and permitting efforts, OHA and its collaborative team installed 26 of the dams along 1,900 feet of Myers Creek in the fall of 2016. They also installed staff gauges at many of the sites to measure both sediment deposit and to provide a reference for photo points over time. Water level data loggers were installed in the stream and in groundwater monitoring wells to measure changes in water surface elevation.

OHA also launched aggressive reed canarygrass management and native planting to help kick-start vegetation recovery. Fourteen planting plots and numerous caged plants were installed throughout the project area. In addition to providing shade, diversity, and stability, it is hoped that these plants will provide a more desirable, extensive food and dam construction source for beaver.

High flows  sustained

The timing of the construction proved fortuitous. When the spring of 2017 again brought exceptionally high flows to the watershed, this stream reach now had enough roughness to force dramatic, restorative geomorphic changes. Instead of further incising the channel, flows overtopped, flanked, and were deflected by the 26 new dams, which helped to widen the incision trench, increase sinuosity, and aggrade the streambed with freshly recruited sediment.

Sediment from the banks and the upper watershed was deposited up to nearly 5 feet in some areas, raising the channel closer to the historic floodplain. After these flow events, an annual survey showed an increase depth of water of over 11 percent in the first season following BDA construction.

Along with the restorative benefits to Myers Creek, this project has also become an important learning site in improving design and function and a training ground for restoration practitioners from around the Northwest wanting to learn how to install BDAs. Volunteers have been a crucial part of the project, contributing over 1,100 hours of service to date, assisting with BDA weaving, riparian planting, monitoring, and education.

One practitioner, Aaron Rosenblum with the Foster Creek Conservation District, found the opportunity to work on the site particularly insightful.

“My two visits to Triple Creek, one pre-peak flow and one post, illustrated to me the utility of BDAs as a restoration tool. The site was completely changed in just a matter of months: sinuosity was increasing before my eyes and several feet of additional water was being stored behind each structure. In Foster Creek, a system with streams that have been historically straightened and eroded, structures like BDAs could greatly help to restore the natural function and condition of the creek and improve water quality.”


Beavers began dam-building shortly after the posts were installed.

 Photo taken in September, 2017 by Julie Vanderwal.

In Triple Creek, project managers were surprised to see that after largely abandoning the site almost twenty years ago, beavers reoccupied the reach just days after BDA construction began in 2016. Their presence, while crucial for long-term maintenance, was initially challenging in that they eagerly ate the desirable willow, which was initially woven into the structures. This necessitated supplemental weaving to maintain the hydraulic benefits of each BDA, while also providing additional willows for the beaver to eat to relieve pressure on the repairs. In 2017, the team adapted their weave material to consist of less-tasty conifer boughs with red osier dogwood, which solved the issue.

Additionally, in the summer of 2017, beavers built a dam on a yet-unwoven BDA, instilling confidence that the long-term goal of beaver-based sustainability is achievable. Beavers also added to the weave material on another BDA where they sealed the dam at the base and provided desirable toe protection. In the latter part of 2017, beavers also built a starter dam just downstream of the downstream-most BDA, adding to project effectiveness much sooner than anticipated.

The long-term vision for BDA projects is that beaver will once again maintain dams to provide local grade control, floodplain connection, and wetland habitats to support a diverse flora and fauna.  Sometimes partners like the Okanogan Highlands Alliance, the Washington Department of Ecology, along with many others, just have to help give them the boost they need.

Beaver caught on camera in the process of dam building at the most downstream BDA. Photo by Julie Vanderwal.

Okanogan Highlands Alliance is a grassroots conservation organization based in Tonasket, Washington.
To learn more about them, the Triple Creek Project, and the other good work they do, go to: www.okanoganhighlands.org.
To learn more about how beaver dams, and beaver dam analogues, help restore stream habitat, go to: https://www.nwfsc.noaa.gov/research/divisions/fe/wpg/beaver-assist-stld.cfm.

By Heather Simmons, Ecology, and Julie Vanderwal, Okanogan Highlands Alliance