Information on Corps of Engineers' Clarence Cannon Dam and Mark Twain Lake Project

In response to a congressional request, GAO provided information on the status of land lease agreements and flooding problems at the Clarence Cannon Dam and Mark Twain Lake site and actions taken by the Corps of Engineers to address flood concerns of downstream landowners, and it updated the project's cost and schedule analysis discussed in a 1977 report.

In 1981, the Corps' temporary dam construction and flood control efforts resulted in flood damage to lands leased above and below the dam, and extensive damage was sustained by the main dam. The land above the dam had been leased by the Corps for agricultural purposes, and the leases stated that the government was not liable for flood damage. However, the lessees filed damage claims on the flooded lands. These claims were denied both by the Corps and GAO because of the nonliability clauses in the leases and because the action which caused the flooding was an exercise of the Corps' discretionary authority to control flood waters and involved no negligence. Investigations have revealed that the maximum flow needed to produce capacity power might still prevent access to some downstream fields. The latest Corps project construction cost estimate was $76 million greater than the 1977 GAO report estimate because of revisions to data, correction of errors or omissions, contract costs, design changes, and inflation. Since the 1977 report, the Corps has revised its cost-estimate manuals to require complete documentation and to allow for inflation. However, GAO found that about 18 percent of the cost estimates for the project are not adequately documented and the scheduled project completion date is now 4 years later than estimated in 1977. Finally, GAO found that the cost-benefit ratio has returned to that projected in the 1977 report.