The Legislature further finds and declares that use of State Highway Route 37 now exceeds the highway’s capacity, and that widening of the highway to four lanes with a minimum amount of fill may only be accomplished in the context of a project to relocate existing sewerlines, to protect private property, and to enhance the ecological values of South White Slough. The Legislature further finds and declares that, because of the unusual circumstances by which tidal influence was returned to White Slough, a combined project may be approved only if all adverse impacts to the environment are mitigated, and the overall effect of the project will be to improve the ecological value of the area.