ASHTON, Idaho — In response to a request from the Federal Energy Regulatory Commission (FERC), PacifiCorp Energy will retain a board of consultants to review the original design and construction of Ashton dam. The consultants will help the company determine the best course of action for any maintenance work needed at Ashton.

PacifiCorp Energy has been working with the FERC and the Idaho State Engineer for the past two years to investigate structural conditions and to determine the need and scope of maintenance work at the dam.

"As we have progressed though the evaluation of the dam’s condition with the FERC and the need for repairs or improvement, it became obvious that we needed a second opinion to answer questions regarding which course of action will best ensure the continued safe operation of the project," said Roger Raeburn, manager of hydro asset planning for PacifiCorp Energy. The additional process is expected to add at least a year to the overall schedule.

The board of consultants will be comprised of two qualified structural engineering consultants and an engineering geologist, all with extensive experience with the design and construction of embankment dams. In discussing a work plan with the FERC, officials there noted certain technical issues regarding the methods and materials used in the dam’s original construction and requested that PacifiCorp Energy retain the consultants to review the company’s plan.

The need to pursue a more detailed evaluation of the dam’s condition was identified in spring 2004. In October 2004 the reservoir was lowered to allow minor repair work on the top of the dam. Officials from the FERC and PacifiCorp Energy have jointly consulted on the issue throughout the investigation process, concluding that the current reservoir level is appropriate to ensure the dam’s safety and should remain lowered until the overall evaluation is completed. It is expected the reservoir will remain about two feet below full for the foreseeable future.

About Ashton Hydro Plant

The Ashton Hydro Plant is owned by PacifiCorp Energy and is located on the Henry’s Fork of the Snake River, approximately 2.5 miles west of the city of Ashton, Idaho. The project began operating in 1914 and was later purchased and expanded in 1925 by Utah Power. The project consists of a dam and powerhouse with three generating units. The dam is a rock and earth filled structure, 60 feet tall and 226 feet long, with a 70-foot-wide concrete intake and 82-foot-long spillway. A roller compacted concrete cap was installed in 1991 to protect the embankment during flood flows. Unit No.1 is rated at 2.85 megawatts. Units No.2 and No. 3 are rated at 2.5 megawatts.

About PacifiCorp Energy

PacifiCorp Energy holds the electric generation, commercial and energy trading, and coal mining operations of PacifiCorp, which provides low-cost electric service through Rocky Mountain Power and Pacific Power. The utility group, part of MidAmerican Energy Holdings Company, serves 1.6 million customers in six western states. The company serves 63,700 customers in southeastern Idaho.