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Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

Metadata Updated: August 19, 2022

The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration approach is to improve their habitat through reconnecting the channel with portions of its former floodplain (now terraces) to increase both stream and riparian habitat complexity. Using conventional restoration techniques to achieve such objectives can be quite costly, because it involves moving and grading large volumes of fill with heavy equipment that exposes bare ground, and is usually followed by extensive revegetation efforts. Here, we seek a cost-effective, process-based approach to restore geomorphic, hydrologic and ecological functions of this degraded system helping a small, extant beaver population build longer-lived dams.

Currently, the beaver population is limited because their dams are short-lived. Most beaver dams are constructed within the incision trench and during high discharge events; the full force of flood waters are concentrated on these dams rather than dissipating across floodplains. Consequently most dams breach and fail within their first season. The primary hypothesis we are testing is that by assisting beaver to create stable colonies and aggrade incised reaches of Bridge Creek, there will be measurable improvements in riparian and stream habitat conditions and abundance of native steelhead. The main restoration design challenge is to help beaver build dams that will last long enough to lead to the establishment of stable colonies. If this can be accomplished, the beaver dams should promote enough aggradation to reverse channel incision and reap a number of well documented positive ecosystem benefits associated with dynamic beaver dam complexes that will benefit steelhead and other species.

We are assisting the beaver using an extremely simple and cost-effective restoration treatment. The treatment involves installing round wooden fence posts across potential floodplain surfaces (now terraces) and the channel, approximately 0.5 to 1 m apart and at a height intended to act as the crest elevation of an active beaver dam. This report provides details of the design rationale and design hypotheses employed and summarizes the placement of the 84 BDS structures installed in four reaches in 2009. Additionally, the ongoing monitoring campaign devised to test these design hypotheses is discussed and some preliminary observations from the first year of the campaign are presented. Five variants of the restoration treatment were used; post lines only, post lines with wicker weaves, construction of starter dams, reinforcement of existing active beaver dams, and reinforcement of abandon beaver dams. The biodegradable posts are intended to buy enough time for (1) beaver to occupy the structures and build on or maintain the structures as their own dams, and (2) for aggradation in the slackwaters of the pond from the dam to take place and promote reconnection with a floodplain (terrace).

Just as with natural beaver dams, individual dams are expected to be transient features on the landscape, expanding and contracting, coming and going as they lose functionality for beaver (e.g. when a pond fills with sediment). The treatment design is geared to saturate four distinct reaches of Bridge Creek with beaver dam support (BDS) structures so that enough potential dams are available to the current beaver population that they can pick and choose the best sites to establish stable multi-dam complexes to support healthy and persistent colonies. Physical and biological data.

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License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Metadata Date August 9, 2022
Metadata Created Date November 12, 2020
Metadata Updated Date August 19, 2022
Reference Date(s) June 1, 2006 (creation), July 14, 2016 (publication)
Frequency Of Update

Metadata Source

Harvested from NMFS NWFSC

Additional Metadata

Resource Type Dataset
Metadata Date August 9, 2022
Metadata Created Date November 12, 2020
Metadata Updated Date August 19, 2022
Reference Date(s) June 1, 2006 (creation), July 14, 2016 (publication)
Responsible Party (Point of Contact, Custodian)
Contact Email
Guid gov.noaa.nmfs.inport:18014
Access Constraints Cite As: Northwest Fisheries Science Center, [Date of Access]: Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project [Data Date Range],, Access Constraints: NA |
Bbox East Long -120.1744
Bbox North Lat 44.5961
Bbox South Lat 44.5861
Bbox West Long -120.1844
Coupled Resource
Frequency Of Update
Harvest Object Id 786a89d1-8964-4a6d-aa84-84f9d6c79484
Harvest Source Id ba43549f-8268-499d-bec8-91b164cb168f
Harvest Source Title NMFS NWFSC
Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
Metadata Language eng
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-120.1844, 44.5861], [-120.1744, 44.5861], [-120.1744, 44.5961], [-120.1844, 44.5961], [-120.1844, 44.5861]]]}
Progress underDevelopment
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2010-01-01

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