The Little Tennessee Watershed Association (LTWA) and its partners recently completed a fish passage assessment for small streams that drain into the Little Tennessee River in the area between the NC/GA state line and Lake Emory in Franklin. The project was funded through a grant from the Southeast Aquatic Resources Partnership, which is a regional collaboration of natural resource and science agencies, conservation organizations and private interests developed to strengthen the management and conservation of aquatic resources in the southeastern United States.
The purpose of the study was to identify areas where fish may be “cut-off” from good habitat in sections of some of these tributary streams. Predominately, these areas are around culverts where a road crosses the stream. Improper placement of a culvert often creates habitat that is difficult, if not impossible, for a fish to swim through. This is a problem because it limits the range of habitat that a fish can occupy.
Just as there are many different types of fish, there are many different reasons for fish to be able to travel along the river and up into smaller streams. Some fish travel to small streams to lay eggs, some to escape warming waters, others to find food, and yet others to avoid being eaten.
Common problems associated with culverts include: not enough water in the culvert (too shallow), too great of a drop below the culvert (waterfall effect), or the “fire hose” effect if the flow through the culvert is too great on a regular basis.
Just as different types of fish have specific behaviors, each species is shaped differently and have various swimming abilities. For the fish passage project, culvert assessments were based for 3 groups of fish. The first group is the strong bodied swimmers such as adult trout. The first group is not the best criteria to rank a barrier since this limits to so few fish. Generally, strong swimming fish use their ability to feed on smaller and slower fish. Thus, just because a trout can access a reach of stream, it may not be beneficial unless its food source can also access the reach.
The second group includes medium skilled swimmers such as young trout and shiners. The final group includes darters which cannot jump well and have the most difficulty swimming against strong currents.
Over the past few months, LTWA has inspected roughly 160 stream crossings. Many times a visual inspection alone can determine if the crossing is a barrier or not.
However, 40 sites required a more elaborate survey to identify if the crossing was a barrier to one or more groups of fish. Teaming up with various agencies such as the U.S. Fish and Wildlife Service, the North Carolina Wildlife Resources Commission, North Carolina Department of Environmental and Natural Resources, and North Carolina Department of Transportation, the Little Tennessee Watershed Association completed the surveys and will now evaluate each crossing for all three groups of fish according to the measurements taken.
This project was designed as a followup to previous cooperative barrier assessment efforts begun in 2007 and the information used from this project will influence future restoration projects in the Little Tennessee River watershed.