The Administrator shall enter into a cooperative agreement with an appropriate public agency or authority of the State of New York under which the Administrator shall maintain or arrange for the maintenance of all properties within the Emergency Declaration Area that have been acquired by any public agency or authority of the State. Ninety (90) percent of the costs of such maintenance shall be paid by the Administrator. The remaining portion of such costs shall be paid by the State (unless a credit is available under section
9604
(c) of this title). The Administrator is authorized, in his discretion, to provide technical assistance to any public agency or authority of the State of New York in order to implement the recommendations of the habitability and land-use study in order to put the land within the Emergency Declaration Area to its best use.