BETHEL — Residents urged the Town of Bethel to strengthen its proposed comprehensive plan with clearer protections for water resources, asking for a formal process for evaluating cumulative impact and firmer procedures for implementing the plan during a public hearing Wednesday evening.

Much of the testimony came from members of the Bethel Roundtable, who thanked the town’s volunteers and consultants for revising the plan while arguing that several areas still needed additional work before adoption.

Denise Frangipane, speaking for the Roundtable, said the plan does not establish a procedure for assessing how several projects together could affect water quality, infrastructure, rural character and residents’ quality of life.

“These impacts can be difficult to see when projects are reviewed individually,” Frangipane said.

She also encouraged the town to establish a more formal process for communicating and collaborating with neighboring municipalities, particularly the Town of Liberty, because development pressures and environmental effects do not stop at municipal boundaries.

Other Roundtable speakers asked the town to extend certain environmental protections beyond the plan’s proposed conservation overlay area. Those protections include waterway , lower thresholds for stormwater review and enhanced septic inspections.

The group also called for protections against light pollution to be listed as a priority action and asked the town to include Mountain Lake among the water bodies specifically identified for conservation partnerships.

Several speakers concentrated on privately operated package wastewater treatment plants, which would serve some developments located outside established public sewer districts.

Residents asked the town to require sufficient reserve funds to replace major equipment, decommission failed systems and cover legal, administrative and personnel costs if a private operator defaults.

Resident Barbara Lerner said the town should retain an independent engineer without ties to developers of similar projects to review possible effects on surrounding water supplies.

She also warned that modular wastewater plants could allow developments to expand over time without sufficient consideration of the added demand placed on the system.

“The bond parameters must be expanded and the bond value reviewed annually and adjusted as needed,” Lerner said.

The comprehensive plan proposes greater town oversight of package plants operated through transportation corporations, along with maintenance and replacement funds intended to protect the town if a system fails.

Other recommendations offered by the Roundtable included updating Bethel’s 2009 agricultural and farmland protection plan, developing a more detailed plan for the Duggan Community Center and requiring hybrid access to meetings of the Planning Board and Zoning Board of Appeals.

Jonathan Hyman said the current language merely recommends that the town consider hybrid meetings.

“We strongly suggest strengthening this to a firm requirement consistent with the transparency and participation values already stated as core priorities in the document,” Hyman said.

Several residents raised broader concerns about White Lake.

Steve Altman, who said he helped write Bethel’s previous comprehensive plan, described declining water clarity, invasive aquatic plants, shoreline pollution and concerns about the capacity of the underlying aquifer.

“You can’t allow all this development right on White Lake,” Altman said. “[There should be] no more development along the lakefront at all.”

Sturm said the board and its professional consultants would review the comments received before determining the plan’s next steps.