To the Editor,

A professional engineer has estimated that 7.5 million cubic feet of granite and other material will have to be removed from Shingle Place Hill for construction of the proposed housing. This is almost as much as the cubic footage of Boston’s Federal Reserve Bank Tower — enough material to cover the entire land mass of Manchester to the depth of one inch. 

We wish to remind Town officials and residents of the inevitable side effects, physical and emotional, of large-scale blasting. Blasts cause air overpressure and ground vibration off-site as well as on-site. Air overpressure makes you want to dive under the kitchen table. Ground vibration travels at different rates through rock, soil, and water, and can affect buildings distant from the blast. 

This is not the first time Manchester is being asked to experience large-scale blasting of its bedrock. Have we forgotten the 1980s, when the area east of Shingle Place Hill was subjected to extended dynamiting? Homeowners on Mill Street and Ledgewood Road reported structural damage, as well as heart-stopping anxiety. Selectmen’s meetings were tense, and community confidence shaken. Assurances that all regulations had been met was little solace. 

Must we return to the 1980s? For those whose homes stand wholly or partially on extensions of the Shingle Place Hill bedrock, the thought of repeated exposures to air overpressure and ground vibration are particularly disturbing. All of us should worry about the impact on our drinking water, and on all the outstanding wildlife habitat within adjacent Town-owned conservation areas.

Clearly, Manchester has an obligation under state law to provide additional affordable housing. But Shingle Place Hill is not the right site. We ask the Selectmen to do all that they can to obviate the need for the SLV project by finding an alternative.

Helen D. Bethell and Ralph C, Smith, Manchester