Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

Metadata Updated: February 8, 2018

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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Dates

Metadata Date April 5, 2017
Metadata Created Date September 26, 2015
Metadata Updated Date February 8, 2018
Reference Date(s) July 31, 2016 (publication)
Frequency Of Update

Metadata Source

Harvested from NOAA CSW Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Date April 5, 2017
Metadata Created Date September 26, 2015
Metadata Updated Date February 8, 2018
Reference Date(s) July 31, 2016 (publication)
Responsible Party (); Northwest Fisheries Science Center (Point of Contact, Custodian)
Contact Email
Access Constraints Access Constraints: NA | Use Constraints: Disclaimer - While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
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
Guid gov.noaa.nmfs.inport:18014
Harvest Object Id cfc0a589-38f2-4827-83ee-803264e2ba09
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence
Metadata Language eng
Metadata Type geospatial
Progress onGoing
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 2010-01-01

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