; and (2) during any five-year period exceed $200,000. (b) Waiver authority In the case of contracts under this chapter for projects of special environmental significance, as determined by the Secretary, the Secretary may waive the limitation otherwise applicable under subsection (a)(1). (c) Prevention of duplication The Secretary shall not approve a contract or provide payments to any individual for a practice that has already been paid for as part of a previously approved and completed contract for any particular parcel of land. .