DEC general permit 3-9050 to take effect Dec. 1; lowers threshold for new development

Padraic Monks of the Vermont Department of Environmental Conservation briefed the Chittenden County Clean Water Advisory Committee on General Permit 3-9050, which he said "goes into effect on December 1, 2020." The permit replaces two earlier general permits and implements Act 64 provisions intended to reduce phosphorus loads to the Lake Champlain TMDL.

Under the new rule, the threshold for new development is reduced to one-half acre, compared with the prior one-acre threshold for new sites. DEC staff explained that any existing parcel of 3 or more acres that lacks a current permit or predates the 2002 stormwater manual will be treated as a 3-acre site for the purposes of this permit. "Sites in the impaired watersheds must obtain permit coverage by October 2023," Padraic Monks said, and he added that projects with permits that expire after Dec. 1 may need to begin compliance work earlier.

DEC told the committee that once a permit is obtained a site has five years to come into compliance with the required stormwater measures. The agency also said applicants can work with DEC on determinations of whether a parcel meets the 3-acre threshold and that existing mapping and data used to identify 3-acre sites will be made available through ANR systems over time.

The briefing included technical and administrative details: standard-setting for new development did not change in substance, but the applicability and administrative processes have been updated under 3-9050. DEC encouraged property owners and towns to contact agency staff with questions about site determinations and next steps.