Civil Engineering ETDs

Publication Date

7-1-2011

Abstract

Stream restoration is a complex process encompassing multiple disciplines and organizations to achieve specific, immediate and long-term goals. Analyses of many completed projects are limited to narrow objectives that commonly exclude the same broad scopes envisioned during the planning process. This thesis studies one completed habitat restoration project in terms of its engineering and biological sustainability using geospatial analysis procedures not widely applied to these goals. These procedures include adjustment of a digital terrain model for hydraulic accuracy, the use of the digital terrain model and aerial imagery for the digitization of features used in hydraulic modeling, and the geospatial analyses of the resulting hydraulic model parameters of depth, velocity, and shear stress to map habitat preferences and discuss sustainability. Methods presented here have application to a broad range of habitat restoration projects, from project planning stages to post-completion monitoring. The Los Lunas Habitat Restoration site was began when a fire decimated the riparian vegetation in the area, opening the door to the site being overtaken by non-native and invasive species proliferating in the area. The goals of the project were to construct habitat preferential to the endangered species, the Rio Grande silvery minnow (Hybognathus amarus) and the Southwestern willow flycatcher (Empidonax traillii extimus), by restoring a natural inundation regime to the overbank area. This inundation regime provides spawning and rearing habitat for the minnow in addition to promoting native vegetation over non-native and invasive vegetation. To evaluate the success of the project, hydraulic modeling and geospatial analysis procedures are undertaken using the most current digital terrain model (collected using LiDAR), a readily available hydraulic modeling software package (HEC-RAS), and the frontrunner of geographic information systems (ArcMap). Features used in hydraulic modeling were manually digitized in most cases although some were assisted using the spatial extent of the LiDAR point cloud. Data exchange between HEC-RAS and ArcMap allowed iterative refinement of the hydraulic model and detailed investigation of results. This detailed spatial investigation is a novel approach to the analysis of a hydraulic model for biological functionality and sustainability of the site. The site shows expansive areas of habitat characterized with the maximum frequency of use by the targeted species. The sediment balance includes both erosion and deposition, but the tendency towards erosion necessitates some maintenance of the project in the future. The reinstatement of a natural inundation regime at the project site shows long-term establishment of native vegetation, which the flycatcher prefers and which is capable of outcompeting invasive and non-native vegetation species. This study concludes that the site is sustainable by continuing to provide habitat to the endangered species targeted for habitat restoration.

Keywords

Riparian restoration--Rio Grande, Riparian restoration--New Mexico-Los Lunas Region, Habitat conservation--New Mexico-Los Lunas Region, Stream restoration--Rio Grande, Rio Grande silvery minnow--Conservation, Southwestern willow flycatcher--Conservation, Hydraulic models, Geospatial data.

Sponsors

United States Army Corps of Engineers

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Advisor

Coonrod, Julie

First Committee Member (Chair)

Thomson, Bruce

Second Committee Member

Stone, Mark

Third Committee Member

Ward, Tim J.

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