Subject to conditions hereafter prescribed, and pursuant to such regulations as may be issued by the Secretary, 25 per centum of the net revenues collected during each fiscal year from the leasing of Klamath project reserved Federal lands within the Executive order boundaries of the Lower Klamath National Wildlife Refuge and the Tule Lake National Wildlife Refuge shall be paid annually by the Secretary, without further authorization, for each full fiscal year after September 2, 1964 to the counties in which such refuges are located, such payments to be made on a pro rata basis to each county based upon the refuge acreage in each county: Provided