In effectuating the water bank program authorized by this chapter, the Secretary shall have authority to enter into agreements with landowners and operators in important migratory waterfowl nesting and breeding areas for the conservation of water on specified farm, ranch, or other wetlands identified in a conservation plan developed in cooperation with the Soil and Water Conservation District in which the lands are located, under such rules and regulations as the Secretary may prescribe. These agreements shall be entered into for a period of ten years, with provision for renewal for additional periods of ten years each. The Secretary shall, beginning in 1980, reexamine the payment rates at the beginning of the fifth year of any such ten-year initial or renewal period and before the beginning of any renewal period, in the light of the then current land and crop values, and make needed adjustments in rates for any such initial or renewal period as provided in section 1304 of this title. In addition, the Secretary shall, beginning in 1980, reexamine the payment rates in any agreement that has been in effect for five years or more in the light of current land and crop values and make any needed adjustments in rates. As used in this chapter, the term "wetlands" means (1) the inland fresh areas described as types 1 through 7 in Circular 39, Wetlands of the United States, published by the United States Department of the Interior (or the inland fresh areas corresponding to such types in any successor wetland classification system developed by the Department of the Interior), (2) artificially developed inland fresh areas that meet the description of the inland fresh areas described in clause (1) of this sentence, and (3) such other wetland types as the Secretary may designate. No agreement shall be entered into under this chapter concerning land with respect to which the ownership or control has changed in the two-year period preceding the first year of the agreement period unless the new ownership was acquired by will or succession as a result of the death of the previous owner, or unless the new ownership was acquired prior to July 1, 1971, under other circumstances which the Secretary determines, and specifies by regulation, will give adequate assurance that such land was not acquired for the purpose of placing it in the program, except that this sentence shall not be construed to prohibit the continuation of an agreement by a new owner or operator after an agreement has once been entered into under this chapter. A person who has operated the land to be covered by an agreement under this chapter for as long as two years preceding the date of the agreement and who controls the land for the agreement period shall not be required to own the land as a condition of eligibility for entering into the agreement. Nothing in this section shall prevent an owner or operator from placing land in the program if the land was acquired by the owner or operator to replace eligible land from which he was displaced because of its acquisition by any Federal, State, or other agency having the right of eminent domain. The Secretary shall provide adequate safeguards to protect the interests of tenants and sharecroppers, including provision for sharing, on a fair and equitable basis, in payments or compensation under this program. No provision of this chapter shall prevent an owner or operator who is participating in the program under this chapter from participating in other Federal or State programs designed to conserve or protect wetlands.