FISHING -- Salmon appear to be migrating up the Columbia River unimpeded by hastily engineered fish ladder extensions prompted by the drawdown and repairs to fix a crack in Wanapum Dam.

However, fish biologists are still concerned whether good fish passage will continue as the river level continues to drop into summer flows.

It's never a good time to have a crack in a dam on a major river, but fish biologists and anglers are sweating the possibility of a setback to years of effort, not to mention billions of dollars, to restore Columbia River salmon runs.

If this year's bountiful runs of sockeye and fall chinook can't make it upstream to spawning areas, the loss would affect the fishery for years.

"So far it looks good because sockeye have been coming up over Priest Rapids Dam at more than 20,000 a day plus a couple thousand summer chinook and they're not stacking up and having trouble getting over Wanapum (the next dam upstream)," Jeff Korth, Washington Department of Fish and Wildlife regional fisheries manager in Ephrata, said last week.

The sockeye run normally peaks over Priest Rapids around July 10, he said. Crowding and chaos could still occur.

From Wanapum, the salmon head up toward Rock Island Dam in a 36-mile stretch of reservoir that's been lowered about 20 feet to accommodate the dam repairs.

"It's interesting that the first six miles below (Rock Island) are flowing much like the original river and we expected the salmon to move up faster than they do under normal reservoir levels and less flow," Korth said.  "But we monitored spring chinook passage and the lower level didn't make any significant difference."

The lowered reservoir behind Wanapum Dam is closed to boating and shoreline foot access mostly to protect archeological sites.

At Rock Island, dam workers already have installed extensions to the fish ladder. They are currently underwater.

"When the flows drop to about 100,000 cfs at the bottom off Rock Island, the extensions will be exposed and we're hoping the fish can move up,” Korth said.

"We won't know for sure until we reach those flows in mid- or late-July."