Following the Flow

Process-based riverscape restoration broadly describes restoring the rates and magnitudes of historically significant hydrologic, geomorphic, and biological processes within the riverscape’s historical footprint (river or stream corridor within a valley bottom). Enhancing surface and subsurface water and sediment detention in headwater streams and wetlands (riverscapes) through process-based restoration has been touted as a tool to enhance the ecosystem services, this natural infrastructure may provide for downstream human needs. Among groups implementing these projects, there has been particular emphasis on the re-establishment of beaver and their works (ponds, dams, canals, etc) within riverscapes (beaver wetland restoration) given their potential to contribute to surface and groundwater detention and sediment capture without continuous human intervention. This project, therefore, is studying streams where beaver wetland restoration projects meet the following criteria:

1) GOALS: beaver recolonization and increases to surface and groundwater detention

2) PROCESS-PATHWAY: beaver mimicry structures induce geomorphic changes that support long-term beaver recolonization, maintenance and expansion

3) TACTIC: beaver mimicry structures

This project is investigating if and how beaver wetland restoration (defined in more detail below) changes the patterns of flows coming into and leaving the study reach as well as any changes in the volume of sediment that accumulates.

1. How does beaver wetland restoration influence surface and subsurface water detention, fluxes, and ultimately stream flow magnitude, duration and frequency at the reach scale (1 to 5 km)?

2. How does beaver wetland restoration influence where and how sediment is detained within a riverscape?

Read more about our research plan and methods  here. 

In practice, process-based restoration (PBR) spans a wide range of restoration strategies and treatments. In general it aims to restore “normative rates and magnitudes of physical, chemical, and biological processes that sustain river and floodplain ecosystems” (Beechie et al 2010). PBR approaches range from “High-Tech”, which may include earth moving equipment and some level of engineering design and modeling, to “Low-Tech”, which can be accomplished with field design and use of natural materials to build temporary structures in support of process restoration.

In this study, we decided to focus on process-based restoration of stream-wetland systems in headwater watersheds that employ low-tech structural treatments that mimic, promote, and sustain natural levels of beaver activity—a strategy that is rapidly growing in use and popularity across the West. Restoration projects with the explicit goal of re-establishing beaver have the potential to detain relatively larger quantities of water and sediment compared to treatments or sites that do not have this goal. However, these projects are subject to the uncertainty and variability associated with beaver mediated natural systems (Nash et al., 2021). Low-tech PBR typically involves the use of beaver mimicry structures (BMS) and post-assisted log structures (PALS) to detain water and sediment, raise the water table, and improve stream conditions for beaver colonization. Ideally, beavers take over maintenance and creation of these structures over the long term.

Each monitoring site slated for restoration has its own unique geography, restoration goals, and project partners. However, all sites either have had beaver established within them in the recent past and/or have some level of beaver presence in or proximal to them.

 _{Beechie, TJ, Sear, DA, Olden, JD, Pess, GR, Buffington, JM, Moir, H, Roni, P, Pollock, MM. (2010) Process-based Principles for Restoring River Ecosystems, BioScience, 60(3): 209–222,  https://doi.org/10.1525/bio.2010.60.3.7}   

 _{Nash CS, Grant GE, Charnley S, Dunham JB, Gosnell H, Hausner MB, Pilliod DS, Taylor JD. (2021) Great expectations: Deconstructing the process pathways underlying beaver-related restoration. BioScience. 71(3): 249–67.  https://doi.org/10.1093/biosci/biaa165}  

Explore our project sites and monitoring locations in detail, below. Zoom and scroll through these hi-resolution aerial images to see how and where we are monitoring streamflow and groundwater. You may also expand the aerial images using the full screen button on the top right. Once these sites have been restored, you will be able to visually explore the changes that result each year.

The Estes Valley Watershed Coalition has been supporting beaver wetland habitat and working to restore beaver wetlands on Fish Creek since the 2013 floods and subsequent emergency repair work severely impacted this creek. The current creek alignment resulted from emergency stabilization measures and lead to approximately six feet of incision through the site, lowering the water table, and disconnecting and drying out the surrounding beaver meadow. One mainstem beaver pond was established in 2023 and several tributary beaver ponds have existed on the site for decades. Restoration work planned for 2026 will plug this channel and re-direct flow to the north side of the valley in the historical channel footprint. It is hoped that this work will facilitate further beaver re-colonization of the site by downstream colonies.

After two major wildfires in the past decade, the Coalition for the Poudre River Watershed has been monitoring and rehabilitating broad, mild sloped valley bottoms or “beads” within Elkhorn Creek, where intense runoff and sediment delivered from burn scars may be attenuated. This work is part of the  Elkhorn Creek Forest Health Initiative , which also includes forest health and fuel management activities. The Lower Elkhorn site, located on US Forest Service land, is one of these beads and is located in a relict beaver meadow. Beaver absence and runoff from post-fire flooding have resulted in the main channel incising two to three feet within the floodplain. Though beaver are not currently present on site, they are within several miles downstream. LTPBR treatments, to be installed in 2025, aim to re-introduce large wood, detain fine sediment that moves through the main channel, support hydrologic connection with the floodplain, and, with luck, foster beaver re-colonization.

Located on US Forest Service land in the headwaters of the South Platte River, the North Tarryall Creek site was a beaver wetland complex for nearly its entire 1.1-mile length as recently as the 1950s, but beaver presence has declined over the subsequent decades.  One to two active beaver colonies are currently present on the reach, though it is still well below its potential capacity for beaver, wetland, and aquatic habitat.  Most of the reach is incised one to three feet and hydrologically disconnected from its floodplain. In partnership with Colorado Open Lands and the US Forest Service, EcoMetrics will perform rehabilitation work on the stream including beaver dam analogs in 2025 with the goal of raising the local water table, distributing surface flows across more of the historical floodplain footprint, and supporting continued beaver re-colonization.

Located on U.S. Forest Service land in the headwaters of the South Platte River, the Lower Trout Creek site was nearly completely occupied by active beaver mediated wetlands over its entire 1.5-mile length as recently as the 1950s but beaver presence has declined to zero in the present day.  Relict beaver dams and canals are present throughout, and most of the site is moderately incised (two to three feet). In partnership with Colorado Open Lands and the US Forest Service, EcoMetrics will install beaver dam analogs in 2025 with the goal of raising the local water table, distributing surface flows across more of the historical floodplain footprint, and supporting beaver re-colonization.

Home to native Colorado River Cutthroat Trout, minnow, and sucker species, the Black Sulphur Creek site supports at least one active beaver colony with relict beaver dams located throughout the over one-mile-long reach.  The Bureau of Land Management and Trout Unlimited identified this site, located in the Piceance Basin, as a good candidate for LTPBR given the importance of its native fish populations, active beaver presence, and its geomorphically degraded state. Restoration treatments, scheduled for 2026, aim to detain sediment, encourage aggradation in incised portions, recruit and retain large wood, and support the expansion of existing beaver colonies.

Draining to Colorado Springs Utilities’ North Catamount Reservoir, North Catamount Creek flows through relict beaver meadows, which have been accumulating some six feet of organic material for (likely) thousands of years. Beaver were extirpated from this watershed in recent decades and the creek has incised one to four feet in many areas, converting the once wet meadow into a “high and dry” valley bottom. As part of Colorado Spring “Wildfire Ready Watersheds” program which includes fuels thinning and road and drainage upgrades, North Catamount Creek will receive LTPBR treatments in 2025 with the goals of reconnecting the floodplain in the valley bottom and enhance the resilience of the North Catamount Reservoir to wildfire and post-wildfire impacts.