Granite State Adaptive asks planning board to accept smaller stormwater footprint using porous pavers

Granite State Adaptive presented a revised grading and drainage plan on Feb. 11, asking the Wolfeboro Planning Board to accept a design change that replaces large retention ponds with permeable pavers, treatment swales and smaller pretreatment features.

The applicant, Jennifer Frazier, identified herself as founder and executive director of Granite State Adaptive and said bids for the site work came back at about $1,200,000, a number she described as burdensome for the nonprofit. Frazier said the organization had previously received site-plan approval and a special exception from the Zoning Board of Adjustment and sought only to amend drainage and grading—not building footprints, parking, access, or the locations of structures.

Engineer Mario Fulcaretto of Brown Engineering described the new approach as a retrofit-style design that reduces impervious area and the project's overall disturbance while managing runoff on-site. The revised plan uses permeable pavers (a grass-over-stone-reservoir system with an underdrain), a long swale along the north side of the driveway and small plunge-pool energy dissipators at outfalls. Fulcaretto said the original design showed roughly 58,600 square feet of impervious surface and the revised design reduces impervious area by about 5,400 square feet. He told the board the project's disturbed area is now below the state's alteration-of-terrain (AOT) threshold of 100,000 square feet (he cited a proposed disturbance around 93,000 square feet) and that the AOT supervisor indicated such a reduction would remove the project from AOT permitting requirements.

Board members questioned infiltration details and maintenance. Fulcaretto said the system includes a network of perforated underdrain pipes (similar to French drains), trench drains at building perimeters, and that larger storms would daylight the underdrains to vegetated areas. He agreed with a commissioner's suggestion to set the perforated pipe slightly higher to increase infiltration opportunity and described maintenance as routine mowing, debris removal, and periodic checks of outlets; he offered an inspection-and-maintenance note that would be included on final plans.

Several board members asked specifically about manure management for the site's composting structure. Frazier said the compost facility is a roofed, three-chamber structure with block walls and airflow; she said composting would be contained and managerially controlled so it would not be a sprawling pile.

The board discussed procedure: applicants said they expected the change could be handled administratively because the buildings and other elements previously approved would not change; several planning board members replied that because the current proposal differs from the plan the board previously approved, the board would need to determine whether the amendment could be handled administratively or must return for formal review. The board did not vote on the technical merits at this meeting and directed staff to advise on the appropriate procedural path for an amendment or a new hearing.

Frazier said the project team would return at a future formal hearing after addressing the board's comments and any plan revisions requested by staff.