Abstract Title

Session S-05E: Managing Floodplain Rehabilitation Success to Inform Decision Making: A Case Study from Hansen Creek, Skagit County

Keywords

Habitat

Start Date

1-5-2014 10:30 AM

End Date

1-5-2014 12:00 PM

Description

This presentation will describe detailed geomorphic and physical habitat observations and monitoring data collected since construction of the Hansen Creek Floodplain Restoration project. Data collected for bedload sediment, large woody debris (LWD), salmonid edge habitat, and channel evolution will be discussed. The previous presentation will discuss challenges related to project planning and funding, while this presentation provides more detailed data, lessons learned, and considerations for monitoring of future projects. Geomorphic changes at the Hansen Creek Floodplain Restoration site occurred immediately after project construction due to higher than average sediment loading associated with a large flood event in 2009. Since the newly planted riparian vegetation had not yet become established, early distributary channel evolution and edge habitat creation in the alluvial fan and wetlands was more strongly influenced by the sediment supply volume and deposition locations, as well as the density of placed LWD structures. In subsequent years with less than average sediment loading, wetland channel evolution has been influenced more by local hydrologic patterns and quickly establishing vegetation. How do we arrive at these conclusions and on what types of observations can we base our understanding of the important relationships between geomorphology and physical habitat so that we can better evaluate success and inform future designs? For Hansen Creek, challenges arose in how, when, and where to collect and compare physical habitat monitoring data for pre- and post-project conditions given the spatial and temporal variability of the geomorphic changes the project area was expected to experience after construction. What is the value in using standard geomorphic or habitat monitoring protocols to compare apples and oranges? Further, how do you prioritize monitoring options with little to no monitoring budget? This presentation discusses the methods and results of early geomorphic and physical habitat monitoring for the Hansen Creek Floodplain Restoration project with a goal of better tailoring monitoring strategies to evaluate restoration success in a highly dynamic alluvial environment. Lessons learned from this project site can be a basis for monitoring in other dynamic alluvial environments.

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May 1st, 10:30 AM May 1st, 12:00 PM

Expect the Unexpected – Monitoring geomorphic changes and evaluating overall effectiveness in meeting project goals and objectives in highly dynamic alluvial environments – Part 2: Geomorphic change, LWD, and physical habitat

Room 613-614

This presentation will describe detailed geomorphic and physical habitat observations and monitoring data collected since construction of the Hansen Creek Floodplain Restoration project. Data collected for bedload sediment, large woody debris (LWD), salmonid edge habitat, and channel evolution will be discussed. The previous presentation will discuss challenges related to project planning and funding, while this presentation provides more detailed data, lessons learned, and considerations for monitoring of future projects. Geomorphic changes at the Hansen Creek Floodplain Restoration site occurred immediately after project construction due to higher than average sediment loading associated with a large flood event in 2009. Since the newly planted riparian vegetation had not yet become established, early distributary channel evolution and edge habitat creation in the alluvial fan and wetlands was more strongly influenced by the sediment supply volume and deposition locations, as well as the density of placed LWD structures. In subsequent years with less than average sediment loading, wetland channel evolution has been influenced more by local hydrologic patterns and quickly establishing vegetation. How do we arrive at these conclusions and on what types of observations can we base our understanding of the important relationships between geomorphology and physical habitat so that we can better evaluate success and inform future designs? For Hansen Creek, challenges arose in how, when, and where to collect and compare physical habitat monitoring data for pre- and post-project conditions given the spatial and temporal variability of the geomorphic changes the project area was expected to experience after construction. What is the value in using standard geomorphic or habitat monitoring protocols to compare apples and oranges? Further, how do you prioritize monitoring options with little to no monitoring budget? This presentation discusses the methods and results of early geomorphic and physical habitat monitoring for the Hansen Creek Floodplain Restoration project with a goal of better tailoring monitoring strategies to evaluate restoration success in a highly dynamic alluvial environment. Lessons learned from this project site can be a basis for monitoring in other dynamic alluvial environments.