N.Y. County Law § 299-O
When the agency has the complete final maps, plans, specifications and cost estimates for a project, as provided in section two hundred ninety-nine-n of this article, the agency shall petition the board of supervisors that a certain area or areas of the county as delineated in the maps, plans and specifications be established as a watershed district.
Proceedings shall be taken in the manner prescribed in sections two hundred fifty-four through two hundred sixty of this chapter in the case of county water districts, as now in effect or as hereafter required, and all of the provisions of said sections shall apply, in so far as applicable, to proceedings for the establishment of a watershed district, except that in relation to the public hearings required by section two hundred fifty-four, only the public hearing by the board of supervisors shall be necessary for the establishment of a watershed district.
The governing body of any municipality within the county may petition the board of supervisors for the establishment of a watershed district. Upon receipt of such petition, the chairman of the board of supervisors shall forthwith refer it to the agency for study and recommendations.
All other requests for the establishment of a watershed district shall be presented to the agency or to the board of supervisors if no such agency exists. The agency or the board of supervisors, as the case may be, shall have authority to prescribe the form, content and manner in which such requests shall be made. The agency, if one exists, shall study such requests and make recommendations thereon to the board of supervisors.
After a watershed district has been created and a project has been approved for construction it shall be the responsibility of the county to require the watershed district to construct, operate, repair and maintain the project works and facilities in accordance with the plans and specifications and to accomplish and maintain the project and purpose for which the watershed district was created.
N.Y. County Law § 299-O