Grant PUD updates status of Wanapum Dam repairs

Wanapum Dam

Contractors are working around the clock in preparation for final reinforcing repairs of a cracked Wanapum Dam spillway, operator Grant County Public Utilities District said.

"Various types of drilling" are already under way as Grant PUD awaits approval for further repairs from the Federal Energy Regulatory Commission, which will include the installation of high-strength cables being installed from the top of the dam into bedrock below. The repairs will also likely include additional reinforcing anchor bars in the upstream and downstream sides of the spillway, Grant PUD said.

All of the repairs in the US$61 million project are scheduled to take place over the summer, allowing Grant PUD to restore the rivers elevation during the fourth quarter of this year.

The company also said fish passage modifications to both of Wanapum Dam's ladders have "proven effective", with more than 23,500 adult Chinook having migrated upstream successfully. Spiral flumes have also been added to existing fish ladders in anticipation of record-breaking sockeye, and summer and fall Chinook runs.

A 38-mile stretch of shoreline from above Wanapum Dam to below Rock Island Dam will remain closed as a public safety precaution and to protect culturally-sensitive sites, Grant PUD said, until repairs at Wanapum are in place.

"While there may be some portions of the shoreline that appear safe, the velocity of water moving through the narrow river channel, and sandy banks creates hazardous conditions for the public," Grant PUD said in a release. "Recreation sites below Wanapum Dam continue to provide recreation opportunities throughout the summer months."

Grant PUD released a preliminary report on the Wanapum Dam fracture in May, which said a 65-foot-long by 2-inch-wide horizontal crack in the structure's pier monolith No. 4 was caused by a mathematical error in the dam's original design calculations.

The discovery led Grant PUD to begin a drawdown of waters upstream of the structure, lowering their levels by more than 25 feet.

The dam is also home to a 1,038-MW Wanapum hydroelectric plant. Grant PUD the plant is only producing about half the electricity it would under normal river conditions.

The facility is a sister plant to the Priest Rapids project. Combined, the two have an output capacity of nearly 2,000 MW.

For more dam safety news, visit here.

Did You Like this Article? Get All the Energy Industry News Delivered to Your Inbox

Subscribe to an email newsletter today at no cost and receive the latest news and information.

 Subscribe Now

Whitepapers

Logistics Risk Management in the Transformer Industry

Transformers often are shipped thousands of miles, involving multiple handoffs,and more than a do...

Secrets of Barco UniSee Mount Revealed

Last year Barco introduced UniSee, a revolutionary large-scale visualization platform designed to...

The Time is Right for Optimum Reliability: Capital-Intensive Industries and Asset Performance Management

Imagine a plant that is no longer at risk of a random shutdown. Imagine not worrying about losing...

Going Digital: The New Normal in Oil & Gas

In this whitepaper you will learn how Keystone Engineering, ONGC, and Saipem are using software t...

Latest PennEnergy Jobs

PennEnergy Oil & Gas Jobs