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USGS Dive Team Completes Installation and Recovery of Samplers in Ashumet Pond, Falmouth, MA
U.S. Geological Survey (USGS) Woods Hole Science Center dive-team personnel Mike Casso, Dann Blackwood, and Rick Rendigs and Field Dive Officer Charles Worley successfully completed the final phase of the installation and recovery of seepage samplers from sediment in Ashumet Pond, Falmouth, MA. The work was undertaken during August 3-6, 2004, in collaboration with Denis Leblanc and Tim McCobb of the USGS Water Resources Discipline. This effort complemented an earlier USGS dive-team reconnaissance study conducted in June 2004 to characterize the occurrence and offshore extent of phosphorus-rich ground water flowing into the pond (see Sound Waves article "USGS Woods Hole Dive Team Deploys Samplers for Study of a Phosphorus Plume"). The source of the phosphorus is a former sewage-treatment plant located on the Massachusetts Military Reservation. The plant, which operated from 1936 to 1995, released treated effluent into infiltration lagoons upgradient from Ashumet Pond. Scientists have long known that phosphorus was leaking into the pond, but the site of its entry—in ground water discharging into the pond along the northwest shoreline—has only recently been mapped. The initial detection of elevated concentrations of phosphorus flowing into the pond came from a cofunded research effort between the U.S. Air Force and the USGS Toxic Substances Hydrology Program. Data provided by USGS scientists from these studies has assisted with planning the location and offshore extent of remediation efforts that have recently begun in Ashumet Pond, where an "iron barrier" is being installed along the pond's northwest shoreline. An area approximately 300 ft long, 40 ft wide, and 3 ft deep will be excavated in the pond bottom. This area will then be covered with a mixture of excavated pond sediment and iron flakes. The phosphorus in ground water flowing through this iron-rich sediment will stick or "sorb" onto the iron mixture, thus reducing the amount of phosphorus that enters the pond. This methodology is expected to trap the phosphorus for many decades. Further monitoring of the pond by USGS scientists will continue after installation of the iron barrier.
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in this issue:
Drilling Monitoring Wells in the Dry Tortugas American Samoa's Resilient Coral Reefs Seepage Samplers in Ashumet Pond
Gulf of Mexico Vulnerable to Hurricanes
Exhibit Designers Interested in Hurricane Research USGS Hosts Science-Learning Session
Deep Water Coral Research Workshop
Four Publications Win Shoemaker Awards Gene Shin Wins Shifting Baselines Contest
Elena Nilsen Joins Coastal and Marine Geology Team USGS Vessel To Test Counter-Terrorism Equipment
Human Influence on San Francisco Bay Floor |
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U. S. Department of the Interior | U.S. Geological Survey
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