Browsing by Subject "Large woody debris"

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Open Access
Evaluation of Pool Habitat Suitability of In-Stream Structures in Restored Streams of Western North Carolina
(2007-08-31T19:47:10Z) Hammontree, Amy
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.
Open Access
Salmon in Trees? Large Woody Debris in Green Mountain National Forest Streams
(2008-04-25T16:59:23Z) Harford, Amanda
Large woody debris (LWD) is an important component of stream ecosystems, especially in regards to fish habitat. It provides shelter for juvenile fish, provides spawning gravel for adult salmon and trout, and is a contributor to organic matter in the stream. Atlantic salmon (Salmo salar) are of particular concern in Green Mountain National Forest (GMNF) in Vermont because they are an endangered species. The fisheries crew at GMNF is working to restore salmon and trout populations in the Forest. This study focused on collecting data on LWD and summarizing the characteristics and organization of LWD in streams in GMNF. I collected data on instream LWD and riparian zone forest characteristics. I aimed to determine whether basal area in the riparian zone could predict LWD volume instream, whether coniferous or deciduous riparian basal area contributed more to instream LWD, and whether the species composition of riparian zones and that of instream LWD was similar. I used linear models and generalized linear models (GLMs) to answer these questions quantitatively. In GMNF, riparian basal area is a significant predictor of LWD volume at the 0.01 significance level. Deciduous basal area is also a significant predictor at the 0.01 level and is more strongly correlated to LWD volume than coniferous basal area. In addition, the species composition of riparian zones and instream LWD is similar. Deciduous basal area and coniferous basal area are highly correlated with their respective LWD volumes. These results provide prediction and prioritization capabilities for the fisheries crew in GMNF. In addition to the results found here, the Northeastern Course Woody Debris model (NE-CWD) created by researchers at the U.S. Forest Service Northern Research Station is being run with the data collected. When the results are available, I will compare them to the field data I collected to determine whether the fisheries crew needs to adjust management activities for LWD. This project provided new products to the U.S. Forest Service in Vermont that were not previously available and will help to adjust the management plan to better manage fish habitat in GMNF, Vermont.