Assessing Changes in Channel Morphology Three Years Following Beaver Dam Analogue Installation
Abstract
Beaver dam analogues (BDAs), stream spanning structures that mimic natural beaver dams, are an increasingly popular stream restoration tool in incised streams in the western US. When installed within streams, BDAs create an upstream impoundment of water that slows flow and is thought to increase water storage, decrease erosive power, and increase aggradation. For this reason, BDAs are installed with the hope that they will bring the same ecologic, geomorphic, and hydrologic benefits as natural beaver dams. Despite their growing popularity, there is limited research on the impact of BDAs on channel morphology, and existing studies often examine short-term changes in morphology (up to one year). Here we assess the geomorphic changes at three BDAs, installed in Red Canyon Creek, Wyoming in April and August of 2018, using survey data and multispectral imagery collected using unoccupied aerial vehicles (UAVs). After one year, previous work found net erosion in both the control reach and the BDA reach. However, theoretical channel evolution models suggest that incised channels will erode and widen before aggradation occurs, meaning that the net erosion and breaching of the BDAs is expected early in the restoration process. Long term monitoring can reveal if this initial erosion gives way to aggradation. We explore patterns of erosion and deposition as well as changes to channel morphology around this small BDA complex, revealing the complex responses arising from the installation of these restoration structures. Overall, this work highlights the need for continuous monitoring of these restoration structures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMEP25B1310H