Cape Cod’s Billion Dollar Cleanup: Talk Outline The Hydrologic Story Denis LeBlanc • The Setting U.S. Geological Survey • The Early Years – Discovery and Action! • Ponds and Plumes • Predicting Flow Paths • The Recharge Mosaic Air Force Center for Environmental Excellence • Today and the Future Toxic Substances Army Environmental Hydrology Program Center Mass National Guard 1975 Environmental & Readiness Center Massachusetts Military Reservation Coast Guard MA ARNG Camp Edwards National Cemetery Environmental Otis ANG Base Programs 1
Water-table altitude, ft 20 Hydrologic section Generalized Hydrologic Section of Western Cape Cod ~ 1 m ~ 1 m 2
1978-79 1986 Operated from 1936 to 1995 MMR Wastewater Treatment Plant 1984 1983 1978-79 Toxic Substances Hydrology Program 3
4 Charles Jacobs
1996 Proposed Treatment System Pumping Well Injection Well “…the National Guard Bureau proposes to replace the natural groundwater flow system with an artificially controlled one that is powered by pumps and electricity.” Thomas Cambareri Barnstable County Hydrologist February 9, 1996 Drawdown in feet 5
Why Pump and Treat 1996 Works at the MMR Plan • Sources mostly removed from unsaturated zone • No known DNAPL below water table • Permeable aquifer has few fine zones 1998 1999 Plan • Quartz sands have little Final sorptive capacity • High recharge and A F E C E C N N ground-water flow rates T E L E E L R F C O R A L E X E N T V I E N R O M N • Large dilute “trace-level AFCEE organic” plumes IRP 1997 SD-5 Plume Ground-Water Flow-Through Kettle Ponds 6
7 For TCE, 50 µg/L in water ≈ 1,000 ppb by volume in air
8 ? 2005 0.5 Miles 2 Miles
Public Water-Supply Wells Cape Cod Recharge Wellfields ~ 1997 1985 22 in/yr Impacted Wellfields 1998 26 in/yr 2007 27-32 in/yr “Are You Sure the RDX Detections April 2000 Kennedys Live Around Here?” “After 62 years of shelling on New Hit England’s summer Source playground, the EPA orders the military to hold its fire” Outside Magazine, August 1997 1/2 Mile 9
2001 2005 4,500 FT Particle Backtracks Perchlorate from Wells Plume 4 with 1 Perchlorate Dec. 2003 18 Detections 4 µg/L Fireworks 1 Launch Area ND 1800 FT 900 FT 10
7/2 ND 7/7 ND Perchlorate in Soils 7/2 ND µg/Kg 7/7 1330 9/23 5.3 2003 7/2 ND 7/2 ND 7/7 1260 7/7 7560 9/18 15 Fireworks 7/2 ND debris 7/7 ND 10/23/03 Fireworks 302 - 34,200 Launch Area µg/Kg MMR Boundary July 5, 2003 Ground-Water Contributing Areas Area Contributing Pumping Wells Ponds, Rivers, and Bays Recharge to a 2 Miles 4 Miles Pumping Well 11
The Ground-Water Plumes Recharge Mosaic and Treatment Systems Water Budget Massachusetts Military In: Reservation Natural recharge 180 Mgal/d April 2007 Onsite systems 7 Mgal/d Solvents and Fuels Out: Explosives and Perchlorate Extraction Well Wells 10 Mgal/d Injection Well or Streams 62 Mgal/d Infiltration Gallery Coast 101 Mgal/d 2007 4 Miles Source: AFCEE/IRP and AEC/IAGWSP April 4, 2007 Current (2007) Ground-Water Treatment Systems Hydro Head Scratchers IRP IAGWSP Major Solvents and Perchlorate and • What is the Recharge Rate? contaminants Fuels Explosives No. of Plumes • How Does “Subtle” Geologic 11 3 Being Treated Structure Affect the Plumes? No. of 53 9 • How Fast Are Contaminants Extraction Wells Transported in the Unsaturated Total Extraction 17.5 1.2 Rate (Mgal/d ) Zone? • How Can Future Plume Cleanup Sagamore Lens of Cape Cod Aquifer (2003) Decisions Better Incorporate (Cape Cod Canal to the Bass River) Water-Supply Planning? Natural Recharge (MGal/d) 252 Pumping for Water Supply(MGal/d) 17.3 Wastewater Recharge (MGal/d) 14.8 12
The Future • Influent of the Treatment Systems Will Approach Non- Detect Levels • Plumes Will Still Be Present, but Dilute and Patchy • Focus Will Be Plume Management in Context of Water Supply • Activists Will Be Water- Supply Managers and Local Officials http://ma.water.usgs.gov/capecodtoxics 13
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