The US Federal Energy Regulatory Commission (FERC) has issued a conditional approval for Ameren Services to start preparing to rebuild the upper reservoir of the Taum Sauk pumped storage plant, Missouri, which breached in late 2005.

Key conditions set by FERC for the rebuild include submission of designs for approval as well as a plan and schedule for impounding the new reservoir. In addition, the conditions include a reforestation plan, reduced effects on wetlands, and re-opening limited recreational facilities at the lower reservoir.

In February, Ameren submitted plans and an environmental report to FERC. The utility envisioned the upper reservoir being impounded behind a new roller compacted concrete (RCC) dam.

FERC added that it also required to meet with all parties concerned with the scheme - Ameren, the design consultant, the Board of Consultants, and the contractor - upon award of the construction contract.

In a letter to Ameren, FERC said it wanted to make all parties aware of its 'authority in the construction process'. It added: 'Given the critical nature of this construction with regard to dam safety and public safety, establishing clear lines of communications prior to construction is essential.'

The final environmental assessment (EA) for the project was issued 14 August following feedback from the public consultation on the draft EA, issued early June.