As used in sections 25-32 and 25-37a to 25-37e, inclusive, “critical components of a stream belt” means (1) the watercourse of a defined stream including banks, beds and water; (2) land subject to stream overflow; (3) associated wetlands, and (4) shorelines of lakes and ponds associated with the stream. “First-order stream” means a stream which directly enters a reservoir; “purity and adequacy of public drinking water supply” means the quality and quantity of public drinking water as determined by the Commissioner of Public Health under subsection (d) of section 25-32; “water company” means any water company as defined in section 25-32a, and “commissioner” means the Commissioner of Public Health.