Rare, Threatened, and Endangered Species
Study for Five Projects in Southwestern Maine
The S.D. Warren Company (S.D. Warren) owns and operates five run-of-the-river hydroelectric projects on the Presumpscot River in southwestern Maine: the Dundee (FERC No. 2942), Gambo (No. 2931), Little Falls (No. 2941), Mallison Falls (No. 2932) and Saccarappa (No. 2897) Projects. These five projects span a river reach of approximately 12 miles. The current FERC licenses for the projects expired in 2001. In 1998, Devine Tarbell & Associates, Inc.’s (DTA) staff assisted S.D. Warren in preparation for its relicensing application by conducting a rare, threatened and endangered (RTE) species study within the project areas.
Determine whether certain state or federally listed RTE species occur within any of the five project areas. Specifically, S.D. Warren requested surveys for six rare plant species, two species of freshwater mussels, the wood turtle, and the bald eagle. DTA’s scientists were also responsible for preparation of a report providing survey methods, results, potential impacts, and mitigation recommendations.
Pre-survey planning performed by DTA’s biologists included a review of aerial photographs and town and city flood way, county soil, state Geological Survey surficial geology, National Wetland Inventory, and U.S.G.S. topographic maps, as well as a review of existing information on species occurrences and habitat preferences from published literature and state and federal agencies. Using these resources, existing habitats within the project areas were classified as unlikely, highly likely or known to harbor the rare resources, or classified as areas of indeterminate status.
Field survey methods varied depending upon the species targeted and the specific survey methods requested by interested agencies. For aquatic plant species, the project area was searched by canoe, while ground searches were used for wetland and terrestrial plant species. Mussel surveys were conducted using a combination of three methods, as appropriate for the sample site. Glass bottom buckets were used to view mussels in the riverbed in the very shallow reaches of the river, while snorkeling was used in deeper water. Also, shoreline surveys were conducted to search for relic shells and evidence of muskrat middens. Wood turtle surveys were conducted by canoe and directed towards locating basking turtles along shorebanks and on suitable basking sites within the river or inlet streams. Traps were set in areas containing the most suitable habitat conditions. Visual surveys for bald eagles and bald eagle nests were conducted in conjunction with all other field studies performed for rare species, with data collected on date and time of sighting, number, approximate age and behavior of eagles seen.
A report on the results of the RTE species study was prepared, subdivided into four sections: freshwater mussels, rare plants, wood turtle, and bald eagle. All sections provided a description of habitat characteristics used to select sample areas for surveying, the field survey methods used, and field descriptions of sites surveyed. The location and number of RTE species found, as well as areas surveyed, were plotted on project base maps.