HVCEO - Housatonic Valley Council of Elected Officials

EAST SWAMP AQUIFER IN BETHEL AND DANBURY, CT


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HISTORIC BASE LINE DATA: 1980
HVCEO REPORT ON EAST SWAMP AQUIFER
A broad wetland swamp of 1.8 square miles, located along the border of Bethel and Danbury just east of Shelter Rock, this aquifer is at the lower reaches of Limekiln Brook and relatively lightly developed, except at the northern end, near its merging with the Still River, at the Still River Middle Aquifer.

Favored by coarse grained structure in its southern half, exceptional depth of possibly 140 feet or more, relatively favorable watershed land use, and strategic location close to the urban centers of Bethel and Danbury, the protection of this potentially significant water supply resource should have very high priority.

View from Shelter Rock Road of Limekiln Brook flowing
over East Swamp Aquifer. Photo courtesy of Rick Gottschalk.

Major wetland areas extending over much of the direct recharge area are still largely undeveloped. At the north end of the aquifer, however, there are several potential problem sites: Danbury’s refuse disposal landfill and road salt stockpile; the Danbury sewage treatment plant; and intensive commercial and industrial use along Newtown Road. A small industrial waste disposal site for metals and solvents is also reported to be located in Bethel near the aquifer’s intersection with Limekiln Brook.

Zoning of the Danbury portion is for general industrial IG-80 and commercial CL-10 and CG-20, in Bethel for one acre residential use R-40. Sand and gravel mining has occurred at scattered peripheral locations.

Records of a number of wells tend to indicate the potential and value of this area. Two producing wells of the Bethel public water system, 138 and 157 feet deep, each have a yield of 400 gallons per minute Other wells, ranging from 76 to 120 feet in depth, have yields between 100 and 250 gallons per minute.

In view of the potential value of this aquifer, and the extensive wetlands, the control strategy should include consideration of eliminating industrial zoning for the undeveloped lands, and full preservation of the wetlands as major recharge areas.

Completion of planned sewer systems, upgrading of the sewage treatment plant and replacement of the landfill by a resource recovery plant as planned, prohibition of deleterious discharges, controls on salt and chemical storage, and strict standards for on-site sewage disposal and site intensity are essential to the protection of this resource.

1988 COMMENT ON WITHDRAWALS
FROM THE EAST SWAMP AQUIFER
In 1988 the CT DEP made review comments upon the Housatonic Water Utility Coordinating Committee's draft regional water supply plan. The following excerpt is relevant to the East Swamp Aquifer:

"East Swamp is tributary to Limekiln Brook, which presently receives treated wastewater from Danbury's Sewage Treatment Plant. By 1991, the Town of Bethel Sewage Treatment Plant will be abandoned and Bethel's flow will be redirected to the Danbury facility.

This regional facility must meet stringent limits to assure Limekiln Brook and the Still River will meet Connecticut 's water quality standards. The limits are established by the assimilative capacity of the receiving stream and to a certain extent, the available dilution. Additional reductions in streamflow in Limekiln Brook will mean additional levels of treatment at the regional facility.

Presently, construction costs for this new facility have been estimated at $45 million. Therefore, there is little potential for establishing new diversions which would further reduce flows during seasonal low flow events in the Limekiln Brook Watershed."

CT DPH ASSESSMENT OF WELL
FIELD IN EAST SWAMP AQUIFER
The CT Department of Public Health has prepared an assessment of the Maple Avenue well field maintained by the Bethel Water Department in the East
Swamp Aquifer.

DEP MANDATORY REGULATORY
AREA IN EAST SWAMP AQUIFER
The CT Department of Environmental Protection provides a map of the mandatory regulatory area, the southern aquifer area on this Bethel map.

2006 BETHEL WATER SUPPLY PLAN COMMENT
Regarding the Maple Avenue Well Field, the 2006 Water Supply Plan states that “Two drilled wells were constructed in 1967 in the East Swamp stratified drift aquifer, which consists predominantly of coarse sand and gravel and is 870 acres in aerial extent. The safe yield for the well field is 1.16 million gallons per day.”

Also, that “The Bethel Water Department has been actively pursuing the development of additional wells behind the Police Station in the East Swamp Aquifer. Water quality and groundwater withdrawal potential has been evaluated and the area deemed a suitable supply development site. Diversion permit applications are currently underway.”