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EPA's Collaboration with the Canaan Valley Institute
Watershed Health Assessment Tools Investigating Fisheries--What If
The Canaan Valley Institute (CVI, a nonprofit outreach organization) and the US EPA are collaborating in the development of modeling tools to address aquatic ecosystem management and restoration. The What If toolkit includes a relational database, help-system functions and documentation, and multiple statistical and simulation modeling tools. The tools consist of a hydrologic and stream geometry calculator, a fish assemblage predictor, a fish habitat suitability calculator, and a process-based model to predict biomass dynamics of stream biota (the BASS model). The tools can be used to assess conditions and associated stressors in aquatic ecosystems, to examine cause of impairment, and to forecast ecological outcomes of habitat alterations and fisheries management actions. What If also supports screening analysis, such as prioritization of areas for restoration and comparison of alternative watershed and habitat management scenarios. The toolkit was originally developed for the Mid-Atlantic Highlands region of the United States in order to support CVI; investigations are underway to transfer the toolkit to other regions. A beta version of Release 2 of this software is available by contacting any of the Principal Investigators.
- Canaan Valley Institute also supports the software through training and hosting on its web site.
CVI is particularly interested in the effects of sedimentation on streams. Sediments are a common stressor throughout CVI's service area (the Mid Atlantic Highlands). CVI needs process/framework and modeling tools to help their stakeholders evaluate management options within a watershed--from Rosgen Natural Stream Channel Design to BMPs to conservation. They need tools that tie sedimentation issues and restoration opportunities to aquatic endpoints, thresholds and landscape drivers.
EPA ecosystems scientists will build upon the current REVA approach, including spatial modeling and indicator queries for possible relationships in environmental data. Expert knowledge for model application, spatial statistics and spatial rescaling will be formalized and incorporated into the user interface as required by the client for management and assessment needs.
The Mid-Atlantic Highlands comprise a biologically diverse and economically active region in the Appalachian Mountains of the eastern United States, where resource extraction and recreation are hoped to ultimately coexist. Multiple uses of environmental resources can be achieved through the application of GIS and modeling tools designed to provide information for restoration outcomes. In addition to ongoing acid mine drainage remediation to decrease metals and increase pH, riparian restoration and Rosgen stream channel design methods are used to stabilize banks, trap sediments in the riparian zone and decrease stream temperatures to encourage trophy trout fisheries. Crucial to widespread acceptance and use of the software is the development of required utilities and decision support tools for model applications. Tutorials, including supporting input data (model parameters and initial conditions), future scenarios, model operations and GIS operations will be provided. Examples are given for fish health and productivity in relation to management scenarios in streams and watersheds.
Watershed Modeling Tools under Development
Habitat Suitability Index Calculator
In most Mid-Atlantic Highland streams, habitat alteration resulting from development in the watershed is the primary stressor for fish. One of the earliest methods to assess the suitability of fish habitat was a series of habitat suitability index (HSI) models published by the U.S. Fish and Wildlife Service in the 1980s. In an HSI suitability scores are developed for multiple habitat characteristics such as water depth, velocity, and temperature, suspended sediment, dominant substrate type and percent instream cover. These scores are then combined into an index of suitability of a stream for a particular fish species that ranges from 0 (unsuitable) to 1 (fully supporting of the species). Although other factors may affect the abundance of a fish species in a particular stream (e.g., species interactions, history, and the presence of point-source pollution), the HSI approach is useful in assessing the quality of streams and their ability to support healthy fish populations.
For example, an HSI for longnose dace is described in: Edwards, E.A., H. Li, and C.B. Schreck. 1983. Habitat suitability index models: Longnose dace. U.S. Dept. Interior, Fish and Wildlife Service, FWS/OBS-82/10.33.
Stream Fish Assemblage Predictor (SFAP)
The SFAP tool allows a user to predict a potential fish community in a stream based on characteristics of that stream and its watershed. This tool is based on information derived from a statistical analysis of environmental data collected by the USEPA in the mid-Atlantic Highlands region of the United States.
There were two major statistical steps taken to develop this tool. The first was a cluster analysis that statistically characterized the fish community in each individual stream, and then formed larger groups of streams with similar fish communities. After performing the cluster analysis, we had approximately two-dozen of these stream groups. We then defined the fish assemblage of each group to be "fundamental," or representative of the Mid-Atlantic Highlands.
It is important to note that the assemblage of fishes defined by one of these stream groups is not identical to the fish community found in any one stream in the set. Instead the assemblage provides a pool of species that could be found in streams of this type.
For example, a given stream group might be defined by a set of twenty species, but actual streams of this type might only have a subset of six to ten species from the total species pool. Stream A could have species 1, 2, 3, 14, 17, and 20, while stream B had species 1, 3, 7, 11, 14, 15, 18, 19, and 20. The streams share four species, but do not have identical fish communities.
The second statistical technique, discriminant analysis, was used for prediction of a stream fish assemblage. Knowing the cluster to which each stream belonged and characteristics of that stream and its watershed (e.g., stream slope, percent forested area in the watershed, stream bank vegetation, latitude, longitude), we derived a system of equations to predict a stream's fundamental assemblage. As noted above, the predicted assemblage provides a pool of potential fish species that could reasonably be expected to exist in that stream, not the actual stream fish community.
BASS is a model that simulates the population and bioaccumulation dynamics of age-structured fish communities. Although bass was specifically developed to investigate the bioaccumulation of chemical pollutants within a community or ecosystem context, it can also be used to explore population and community dynamics of fish assemblages that are exposed to a variety of nonchemical stressors such as altered thermal regimes associated with hydrological alterations or industrial activities, commercial or sports fisheries, and introductions of non native or exotic fish species.