Commission Reviews Aquifer Impact Of Condo Expansion Plan

By Andrew Gorosko

Conservation Commission members are conducting an “aquifer protection review” to gauge the environmental effect that expanding the Walnut Tree Village condominium complex would have on the underlying Pootatuck Aquifer.

Conservation members April 12 received scientific and engineering reports from Walnut Tree Developers, Inc., which wants to increase the Walnut Tree Hill Road condo complex from 80 units to 190 units. The developers started construction on the 80-unit complex on an 18-acre site on Walnut Tree Hill Road in Sandy Hook in 1995. They now want to build another 110 units on an adjacent 34-acre site. The new units would be served by a public water supply and sanitary sewers, as are the existing units.

 Conservation members modified and reapproved the developers’ wetlands construction permit and tree cutting permit for an expansion project, which were issued in March 1999. Those permits had been issued when the developers were proposing building 133 new units on the site. Planning and Zoning Commission (P&Z) members rejected the 133-unit expansion project last November, resulting in the developers returning to the town with scaled back plans for 110 units.

The proposed 133-unit expansion project had not been subject to the town’s aquifer protection regulations, which took effect last June.

The modified expansion plans propose 18 new residential buildings, instead of 22 new residential buildings. A proposed private road would be realigned to lessen the amount of earthmoving needed for the project.

Residential buildings would be moved back farther from the street than earlier proposed to increase the amount of parking space in driveways. The elevations of some proposed buildings would be raised to better balance grading work within the town’s Aquifer Protection District (APD).

The developers propose building the expansion project in three distinct construction phases as a way to limit erosion and sedimentation problems in the area.

 About 9.7 acres of the 34.1-acre development site is in the APD. The 9.7 acres is in the Pootatuck Aquifer’s “secondary recharge area.”

About 19.4 acres of the 34.1-acre site would be disturbed by construction. When completed, 10.3 acres of the disturbed area would be covered with vegetation, and 9.1 acres would be covered by impervious surfaces such as roads, driveways, parking areas, and roofs.

The developers have submitted engineering, geology, and turf management plans for Conservation Commission review. The turf management study focuses on controlling the use of fertilizers and pesticides to prevent environmental damage to the aquifer.

 Conservation Commission action on the aquifer protection measures is required by mid-May. The Walnut Tree Village aquifer protection review is one of the first such reviews conducted by the town since the aquifer protection regulations took effect last June.

  The aquifer protection regulations are intended to better safeguard the quality of existing and potential underground drinking water supplies in the Pootatuck Aquifer, the town’s sole source aquifer. The regulations greatly expand and more explicitly state the rules the P&Z uses to protect groundwater quality in the APD.

The APD, which was approved by the P&Z in 1981, contains the Pootatuck Aquifer, an area of varying width, which generally follows the course of the Pootatuck River through town from its headwaters in the vicinity of the Monroe border northward to Sandy Hook Center. The proposed rules apply to “stratified drift” aquifers, or those such as the Pootatuck Aquifer, in which subterranean water supplies are contained within layered bands of sand, gravel, and boulders.

The regulations seek to protect groundwater quality by prohibiting within the APD land uses that can contaminate groundwater, and by regulating other land uses which may potentially contaminate or downgrade existing and potential groundwater supplies. The aquifer is susceptible to contamination due to its high porosity and shallow water table which is recharged mainly by precipitation that sinks into it from the ground surface above.

If the Conservation Commission finds that proposed construction would substantially adversely affect the aquifer, the P&Z would be required to muster four positive votes out of five votes to approve a special exception to the zoning regulations for the development project.