Upon entering a cooperative agreement under subsection (i) of this section, the Administrator may provide to the applicant, on a matching basis, a grant of 50 per centum of the costs of implementing the plan established under this section. The Administrator may also reimburse the applicant of an approved plan up to 50 per centum of the costs of developing such plan, except for plans approved under section 208 of the Clean Water Act [
33 U.S.C.
1288]. The total amount of grants under this section for any one aquifer, designated under section
300h–3
(e) of this title, shall not exceed $4,000,000 in any one fiscal year.