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Solarest project at 374 Hazel Street continued after engineers and peer reviewers exchange calculations
Summary
Applicant for a solar and stormwater permit at 374 Hazel Street introduced new calculations for an emergency secondary-containment basin and a proposed maintenance surety; the commission asked the peer-review engineer to verify containment-volume math and continued the hearing to May 19.
Tom Corbett, representing the applicant for the 374 Hazel Street notice of intent and stormwater management permit (DEP 3121184 / SWM08), described a number of technical revisions to the project’s stormwater and containment designs and asked the commission to accept updated calculations and an operations plan.
Corbett said the applicant has added additional documentation responding to Graves Engineering’s peer-review comments and submitted a letter from McCarty Engineering that included storage and secondary containment calculations for fuel and fire-water storage tied to the site. The applicant proposed a surety for stormwater maintenance and inspection in the amount of $5,000, made up of two $2,500 components for biannual inspections and periodic maintenance.
Commissioners pressed for an independent review of the containment calculations. The applicant’s engineer described the containment as a stone-filled vault wrapped in a polyvinyl membrane; he said the commonly used engineering factor is that 1 cubic foot of washed stone holds roughly 3 gallons, and that the containment volume would therefore be in the 12,000–13,000-gallon range. The commission asked Graves Engineering to confirm the factor and the volume math. "We can have Graves review," Corbett said.
Commissioners also sought a clearer peer-review stamp or written verification from Graves on the specific calculations for the containment and an operations-and-maintenance (O&M) plan showing inspection frequency and maintenance triggers. The applicant proposed monthly checks of forebays, early storm inspections for the first three months, then twice-yearly basin inspections, mowing of basins twice per year, and sediment removal triggers tied to measurable thresholds.
The commission voted to continue the hearing to May 19 to allow Graves to review the new calculations and for staff and commissioners to review the updated O&M and surety proposal. Corbett told the commission he intends this to be the last round of plan revisions and said the applicant will coordinate with Graves and the commission on surety language and the bond form before the next hearing.
