Evaluation of Pool Habitat Suitability of In-Stream Structures in Restored Streams of Western North Carolina
Abstract
Abstract
Evaluation of Pool Habitat Suitability of In-Stream Structures in Restored Streams
of Western North Carolina
by
Amy Hammontree
August 2007
One of the most critical aspects of stream restoration is the creation of suitable
aquatic habitat. Much of this work is accomplished through the installation of both
hard and soft in-stream structures. The structural stability of these practices has
been well studied and monitored for decades. However, the evaluation of habitat potential
of these structures has remained almost entirely qualitative and categorical.
The objective of this study aimed to fill this void by quantitatively evaluating the
habitat potential of a variety of common in-stream restoration structures and bend
treatments in Western North Carolina through the measurement of common habitat features
such as pool depth and length, distance to cover, and depth of cover (or undercut),
with the ultimate goal of providing design recommendations for stream restoration
projects listing habitat enhancement as a top priority.
In analyzing the results of the study, high habitat quality was defined by large pool
depths (for increased niche space and low flow velocities), small distances to cover,
(for faster escape from predation), and large cover depth or undercut values, (for
shelter, predation, and rearing). Collectively, soft structures provided the deepest
pool depths, with shorter distances to cover and larger cover depth values than corresponding
hard in-stream structures. Likewise, bend treatment groups containing soft in-stream
structures also excelled in these areas. Bends containing hard structures produced
much higher pool lengths, in many cases longer than the curvature of the bend itself.
Design goals based on habitat enhancement of small streams should focus heavily on
the installation of rootwad revetments and cover logs for creation of deeper pools
with increased flow variation and increased cover depth. In addition, both these structures
will also serve to promote the acquirement and continued recruitment of large and
small woody debris into the streams. Where hardened structures are deemed necessary
for structural or hydrologic purposes, they should be accompanied by soft in-stream
structures to create combination bends to supplement habitat within these areas.
Type
Master's projectPermalink
https://hdl.handle.net/10161/400Citation
Hammontree, Amy (2007). Evaluation of Pool Habitat Suitability of In-Stream Structures in Restored Streams
of Western North Carolina. Master's project, Duke University. Retrieved from https://hdl.handle.net/10161/400.Collections
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