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The Problem
Aquatic habitats of most large, multipurpose river systems have been substantially altered to accommodate varieties of social and economic purposes, including flood control, navigation, hydropower, and public water supply. Physical barriers imposed by dams, levees, and bank revetments, combined with flow regulation, have resulted in loss of longitudinal and lateral connectivity, disruption of migration pathways and energy and nutrient fluxes, and fragmentation and degradation of aquatic habitats. While many ecological aspects of large-river alteration have been investigated previously, there has been little emphasis on how alterations of physical habitat interact with life histories, biotic interactions, and competitive strategies of native and invasive species. The USGS Western Fisheries Research Center, Columbia River Research Laboratory (CRRL) and the Columbia Environmental Research Center (CERC) are collaborating on a multiyear effort to develop approaches to better understand the role of large river geomorphology, flow patterns, and water management on the prevalence of invasive species. The Centers have unique capabilities that will be brought together to provide resource managers with information that can be used to better understand management opportunities for the habitats and aquatic resources of large rivers. Objectives The general objective of this collaborative project is to investigate and improve habitat-based ecological modeling on large rivers. We plan to explore cost beneficial approaches to hydraulic habitat modeling on large rivers including consideration of scale, data requirements, nesting of 1, 2, and 3-dimensional models, and potential to address sediment transport as a critical factor in habitat maintenance. Optimum methods to model biotic responses to habitat will be examined, including models based on data collected from telemetry systems, conventional fish and invertebrate sampling, remote sensing, and hydroacoustics. Methods will be developed using comparative studies on the causes and effects of habitat fragmentation in large rivers. Methodology
Each center will conduct detailed mapping of riverbed elevations, bedforms, substrate, and velocity fields for discrete, representative sections of the Missouri and Columbia rivers. From this information, additional habitat descriptors such as lateral and longitudinal bed slopes, habitat fragmentation, and habitat contiguity will be derived. Multidimensional hydraulic modeling will provide additional information on water surface gradients, and velocities that can further characterize aquatic habitats. Consultations and field visits will ensure coordinated approaches and information transfer. The Centers will use this suite of empirical, derived, and modeled data to develop a classification scheme to compare, contrast, and report on habitats found in large rivers. The CRRL will conduct surveys of two sessile organisms (Eurasian watermilfoil Myriophyllum spicatum L. and the Asian clam), while the CERC will evaluate effects of habitat distributions on mobile organisms (Asian carps, primarily bighead and silver carp). We will develop and validate models to predict the occurrence/distribution of selected invasive species under existing habitat conditions. We will evaluate the potential influence of different water management strategies or physical habitat manipulations on the distribution and relative abundance of invasive species, using the integrated physical/biological understanding afforded by this study. This component will explore whether water or habitat manipulation can be used to minimize deleterious effects of invasive species, or if instead, well-intended restoration activities could result in enhancing habitat for invasive species. Highlights and Key Findings This is a new project beginning in late FY02 so no highlights or findings are available at this time. Where Are We Headed In 2003 One of our first tasks will be development of high-resolution bathymetric data for the Bonneville Reservoir, in collaboration with the Geologic Division of USGS. This bathymetric data will form the basis for a hydraulic model of water flow and elevation within the reservoir, which we will begin to develop. Substrate data will be compiled for this reservoir, and new collections made where necessary. Bonneville Reservoir will be surveyed for Eurasian watermilfoil, an important invasive species, and we will explore the feasibility of using remote sensing data to determine distribution of aquatic macrophyte beds. Collaboration with the Columbia Environmental Research Center will be ongoing, with exchanges of information, techniques, and expertise. Project Contact James H. Petersen and Timothy D. Counihan Email: jim_petersen@usgs.gov Publications |
