(a) All structures to be built over, or structures or embankments to be built adjacent to, streams in connection with state highway projects shall conform (1) to the requirements of the Commissioner of Energy and Environmental Protection for sizes and location of waterways as determined by his policies for the establishment of river channel encroachment limits in accordance with sections 22a-342 to 22a-348, inclusive, (2) to any approved river corridor protection plan for a river corridor designated pursuant to § 25-205, and (3) any river corridor management plan approved pursuant to § 25-235.

(b) On any stream subject to flood control measures by the Commissioner of Energy and Environmental Protection over or adjacent to which such a highway may be constructed, the size of waterway for such bridges, structures or embankments shall be increased sufficiently beyond that required to comply with channel encroachment policies to avoid any reduction in the protection afforded by the flood control measures.

(c) Highway bridges in existence on June 21, 1961, crossing streams on which flood control projects are carried out shall be rebuilt or modified by the Commissioner of Transportation to meet the requirements of the flood control plan.

(d) In connection with highway improvement projects initiated by the commissioner, the entire cost of new or modified existing structures over, or structures or embankments adjacent to, streams designed to comply with river channel encroachment requirements as specified in subsection (a) of this section may be paid from regular highway construction appropriations, and any additional costs required to provide structures meeting the needs of flood control measures above that required to comply with river channel encroachment policies shall be paid from the other appropriations provided for such flood control purposes.