Committee pauses direction on 3‑acre stormwater rule, seeks more ANR detail before study

Members of the Natural Resources & Energy committee on Thursday opened a detailed discussion of a planned study of the state’s 3‑acre stormwater threshold and related implementation schedule, but held off directing staff while seeking more information from the Agency of Natural Resources (ANR).

The committee’s focus was the study language in a draft starting on page 11 and the consequences of changing the rule that currently captures parcels of three acres or more for more stringent stormwater controls. “I would like to not be here having the same discussion in three years,” a committee member said, pressing for a study that resolves outstanding technical and equity questions now rather than later.

Committee members said the 3‑acre threshold derives from modeling tied to the federal Total Maximum Daily Load (TMDL) for phosphorus in impaired waters. As explained in the meeting, when the Environmental Protection Agency and ANR modeled required phosphorus reductions they “backed into” an amount of stormwater-managed area that corresponded to roughly three acres; lowering the acreage threshold would change how the model apportions required reductions and could shift the regulatory…