The industry of river restoration has for decades leaned on concepts of channel stability as a primary mechanism for restoring impaired river systems. So much of contemporary river restoration design and implementation focuses on stabilizing channels and streambanks as primary restoration tactics to reverse impairment or improve habitat and water quality. What is ‘stability’? Where does this emphasis come from? Is it justified and appropriate? Is stabilization moving us toward goals of improved and healthy river systems? 

There is a fundamental disconnect between restoration practice that emphasizes stability of channel and streambank form and the science that explains how river systems function and what factors and processes maintain river health. The scientific fields of study of fluvial geomorphology and aquatic and riparian ecology highlight the critical functions and interactions among channel migration, aggradation and degradation, and plant succession processes that ultimately create and maintain river health, aquatic habitat, and water quality. Rivers are inherently dynamic systems in a constant state of adjustment to maintain dynamic equilibrium – a balance of inputs and forces that maintains the character and health of the system. Yet the restoration industry broadly and regularly integrates and implements features intended to limit the dynamic state and associated channel adjustments.

This presentation will explore the mystique and folly, origins and implications of the industry emphasis on stability in river restoration to shed light on What’s Working and What’s Not and to advance Forward-Thinking Approaches to Management.

Peter Skidmore

Peter Skidmore is Principal of Dipper Consulting, working to protect and restore healthy river systems. Peter was previously Senior Program Officer at the Walton Family Foundation for their Colorado River program. Peter is a Professional Geologist with a degree in Water Resources Geography from Montana State University and expertise developed through his career in hydrology, geomorphology and riparian ecology. Peter has focused his 30+ years career on improving outcomes for river restoration and conservation including work in restoration design, conservation planning, river management guidance and training, and river-focused philanthropy and NGO leadership. When not working, Peter spends most of his time enjoying wild places on public lands.

The Boulder Watershed Collective (BWC) works to cultivate partnerships and revitalize social and ecological systems. BWC intimately understands the inseparable relationships of forests and streams, wildfires and healthy riparian corridors, and ecosystems and the people living, working and recreating within them. In 2020 after large wildfires occurred in Boulder County, BWC conducted a Sediment Source and Storage Study for Disaster Planning. This study laid the groundwork for a multi-strategy approach to meadow, riparian and stream restoration - in particular, initiating BWC’s beaver coexistence and relocation projects. 

As BWC has built out the beaver reintroduction and restoration program and aspires to be a local conduit for beaver coexistence support, more could be understood about perceptions of beavers among public agency managers across the Front Range. Especially critical is determining the degree to which beaver management planning and coexistence has occurred within public agencies in conflict areas and how the perceptions of beavers have influenced management decisions. 

BWC is working with select CU Master’s Students to conduct a comprehensive summary of Front Range municipalities, water management agencies, parks districts, and other resource manager’s current perceptions of beaver management, coexistence, and the nuanced challenges and successes of public land management for beavers. This summary will reflect dozens of interviews with watershed restoration experts, agency personnel and resource managers who have been influential in guiding beaver management practices and policies across Colorado, as well as a wide-ranging survey of practitioners who are responsible for managing and mitigating conflicts with beavers. This work ultimately highlights BWC’s vision to expand beaver populations into areas they are needed for watershed restoration, while maintaining beavers across diverse sectors and providing resources, expertise, and guidance for informed, collaborative, and forward-thinking beaver management policies and decisions across various landscapes of the Front Range.

This proposed 30-minute presentation addresses a key question that both the water and stream restoration communities are asking: how does beaver restoration influence stream flow?

Beavered stream corridors influence the rate, magnitude, and timing of water and sediment movement through a watershed. Stream corridors with beaver complexes have demonstrated the ability to attenuate flood peaks and detain sediment. Impacts on non-peak stream flows (e.g., summer and fall base flows) are less straightforward.  A hydrologic and sediment monitoring program established in 2023 and sponsored in part by CWCB is evaluating surface and subsurface hydrologic and sediment response to stream rehabilitation projects across the State of Colorado whose goal is beaver recolonization, supported with beaver mimicry structures.

Six sites slated for rehabilitation in 2025 – 2026 have been instrumented with stream gaging stations bracketing the treatment reaches and groundwater elevation monitoring transects. I present my baseline findings of seasonal patterns of stream flow, water balance, and groundwater elevation, along with sediment storage. Pre-treatment, baseline data collected in 2023 and 2024 demonstrates that reach-scale water balance is net positive or gaining (Qout – Qin > 0) during the spring runoff and early summer. Then, depending on the magnitude of hillslope or tributary water inputs, as well as the depth of a confining layer, these streams typically become losing (Qout – Qin < 0) later in the summer and fall as the water table falls below the stream bed. Summer rain events can temporarily reverse this trend as can the end of the growing season when vegetation becomes dormant. A literature review of beaver pond impacts on stream base flow indicates a mixed response. I present a conceptual model of how post-restoration stream and groundwater flow may behave based on literature and observations from beavered stream corridors.

Joel Sholtes

Joel Sholtes, PhD, PE is an Associate Teaching Professor in the University of Colorado, Boulder – Colorado Mesa University Engineering Partnership Program in Grand Junction, Colorado. He is also Principal Engineer at Wash Water Science and Engineering, LLC. Joel’s work and research focuses on studying physical stream processes related to water and sediment to inform managing stream corridors along with the outcomes of stream restoration. He helped develop the CWCB Fluvial Hazard Zone Program and is currently studying the hydrologic impacts of riverscape restoration in headwater streams in Colorado. Joel is also a founding member of the Grand Valley River Corridor Initiative.