Sponsored by the Geomorphology Specialty Group
Association of American Geographers 103rd Annual Meeting
San Francisco, California, April 17-21.
Environmental and Ecological Restoration II
Paper Session 3201
Thursday, 4/19/07, from 10:00 AM - 11:40 AM
Biogeography Specialty Group
Geomorphology Specialty Group
Joy A. Fritschle - University of Connecticut
Melinda Daniels - University of Connecticut
Melinda Daniels - University of Connecticut
- 10:00 AM Author(s):
*Marc R. Owen - Ozarks Environmental and Water Resources Institute (OEWRI), Missouri State University
Robert T. Pavlowsky - Ozarks Environmental and Water Resources Institute (OEWRI), Missouri State University
Mark A. Gossard - Missouri State University
Timothy W. Smith - Greene County Resource Management Department
Abstract Title: Channel Restoration in Urbanizing Streams of the Ozark Plateaus, Greene County, Missouri.
Channel instability due to urbanization has impacted streams around the Springfield, Missouri metropolitan area resulting in flooding, bed scour, bank instability and increased sediment yields. Ozarks streams have gravel or bedrock beds and banks are composed of chert gravel and fine grain material that is fairly resistant to erosion. Due to karst, many streams have losing sections and/or have spring discharges that along with changes caused by urbanization complicate the understanding of low flow hydrology critical to evaluating channel forming flows. Regionally, no channel restoration guidelines are available and Ozark stream channel response to urban hydrology is poorly understood. The study reach is part of the Ward Branch of the James River located on the south side of Springfield, which has encountered rapid urban growth over the past two decades. The reach is located in an area where Greene County Missouri purchased and removed homes affected by flooding from recent developments. The objective of this project is to use bioengineering techniques and natural channel design concepts to stabilize this section of stream and provide guidelines to developers, contractors and design professionals on the process necessary to implement these techniques in the field. This paper will describe the role of geographers in the multidisciplinary team's approach used to implement the project's objectives focusing mainly on fluvial geomorphology. Geographers collected field data, assisted in the location and design of stream remediation practices, and are responsible for pre and post restoration monitoring of the reach.
Keywords: Stream Restoration, Fluvial Geomorphology, Ozarks Streams
- 10:20 AM Author(s):
*Pollyanna Lind - University of Oregon
Pat McDowell - University of Oregon
Jim O'Connor - USGS
Abstract Title: Geomorphic and hydrologic connections between floodplain springs and the Sprague River, Oregon.
The Sprague River is important spawning and rearing habitat for two species of sucker listed under the Endangered Species Act, as well as other aquatic and terrestrial species. While the river does not meet state water quality standards, artesian springs within the floodplain provide an important influx of cool water that supply critical spawning habitat and thermal refugia. Most of the springs are connected to the river channel by a spring brook even at low flow, so access to the springs is viable. Understanding how these connections are created and maintained, and the relative roles of spring flow and river flow, is important for habitat restoration. All springs are inundated by the river at bankfull flow or lower. Spring pools either create their own complex network of brooks to the river channel or they are set in abandoned meander channels that control the form of the connective brook. For some, the abandoned channel and the spring remain influenced by fluvial river inflow. For others, the upstream portion of the meander scar has been filled by deposition such that inundation occurs only during over-bank events or seasonal high water back-flow. Discharge from the springs is substantial enough in all but one spring to flush out fine deposits and maintain a medium-to-coarse sand and gravel substrate in the pools and brooks. There is concern about river migration away from some springs and some active restoration projects have been done to maintain spring-river connections.
Keywords: springs, floodplain, Sprague River, sucker, habitat
- 10:40 AM Author(s):
*Peter Downs - Stillwater Sciences
Maia Singer - Stillwater Sciences
Abstract Title: Re-establishment of physical and biological integrity in fragmented rivers lacking a credible reference condition: lower Merced River, California.
In many rivers regulated by large dams, changes to the river's morphology, hydrology and sediment regimes are so profound, and longitudinal and lateral disconnection so complete, that no credible reference reach exists as the basis for restoration. In these fragmented rivers, restoration must use exploratory field data along with predictive and empirical models to improve system integrity. The lower Merced River is both disconnected from its upper watershed, and further fragmented in the "dredger tailings reach" (DTR) from historic gold mining which has laterally disconnected the floodplain. The DTR is now a focal reach for restoration planning because upstream fish passage restrictions make it a primary spawning area for anadromous fall-run Chinook salmon and, potentially, the endangered Central Valley steelhead. Restoration planning has necessarily involved "naturalization": the establishment of a new ecosystem where morphological and ecological configurations are designed to be compatible with contemporary altered flow and sediment transport regimes. There are four primary restoration challenges for the DTR: 1) stimulation of an effectively "paralyzed" river channel, 2) improvement of highly sub-optimal habitat for native aquatic species, 3) re-establishment of native flora and fauna on a floodplain comprised of unconsolidated dredge tailings, and 4) protection of the ecosystem from the potential mobilization of bioavailable mercury. Baseline studies and numerical modeling were used to develop restoration proposals that acknowledge ecosystem creation and the management commitment required to sustain the improvements. A rigorous monitoring plan has been devised to evaluate the project, and also to maximize the transferability of the learning experience.
Keywords: river restoration, California, fragmentation, reference reach
- 11:00 AM Author(s):
*Melinda Daniels - University of Connecticut
Anne Chin - Texas A&M University and The National Science Foundation
Wendy Bigler - Southern Illinois University
Kathryn Boyer - USDA Natural Resources Conservation Service
Anya Butt - Central College
Stan Gregory - Oregon State University
Martin Lafrenz - Portland State University
Michael Urban - University of Missouri
Ellen Wohl - Colorado State University
Herve Piegay - University Lyon III
Kenneth Gregory - University of Southampton
Yves Le Lay - University Lyon III
Abstract Title: Perceptions of Wood by River Managers: Challenges for Stream Restoration.
This study presents results from a survey undertaken in several regions of the United States to assess how people involved in river management perceive wood in rivers. Using a web-based questionnaire, river managers at the local, state and national levels were asked to evaluate images of streams and rivers with and without wood present. The respondents rated the images according to how aesthetically pleasing they appeared, how natural they looked, how dangerous they felt, and whether the scenes needed improvement. This study builds on a \survey undertaken in 10 countries to assess how students perceive of wood in rivers (Piegay et al., 2005), and complements similar surveys of river managers in France and Poland. The perceptions of river managers are discussed in light of challenges for stream restoration in mountain watersheds in the United States and elsewhere.
Keywords: fluvial geomorphology, woody debris, river restoration