Weather

Boise to build flood barrier around zoo, expects less advance notice of rising river

'Muscle wall' installed next to levee

The “muscle wall” installed near the gravel pit on Eagle Island joins a 4,000-foot temporary levee installed by the Army Corps of Engineers and the 600-foot flood diversion tube put in by Ada County last month.
Up Next
The “muscle wall” installed near the gravel pit on Eagle Island joins a 4,000-foot temporary levee installed by the Army Corps of Engineers and the 600-foot flood diversion tube put in by Ada County last month.

Evacuating Zoo Boise’s 200-plus animals could cost $500,000 to $600,000 and put the zoo’s animals under a significant amount of stress, the city of Boise noted Tuesday.

To avoid that, the city will start Wednesday to install a 2,000-foot-long flood barrier amid concerns it will get less advance notice about future water-level increases in the Boise River.

Tuesday afternoon, the river’s flow was at 9,400 cubic feet per second at a gauge at the Glenwood Bridge. Boise officials say they’ve been told federal water managers have no plan to immediately release more water through upstream dams. But the city was warned current weather conditions may mean only a 24-hour heads-up the next time the river rises. In recent weeks, water managers have announced increases to the river’s flow several days in advance.

“Chances are if we do decide we need a flow change, it would be 24 hours or less (to give notice),” said Army Corps of Engineers spokesman Brandon Hobbs.

Hobbs said that as of Monday, reservoirs were at 93 percent capacity.

“Given how close we are to full, it’s prudent to prepare for (higher flows),” Hobbs said.

The “muscle wall” barrier around the zoo will measure 2 to 4 feet high and cost about $130,000, with $118,500 of that total covered through a grant from Ada County Emergency Management, according to the city. Other agencies within Ada County that have partnered on flood response will help install it over a day or two.

It’s similar to one installed last month to protect a gravel pit on Eagle Island.

“We are doing this out of an abundance of caution to ensure we are not faced with planning a full-scale evacuation of zoo animals on short notice,” said Doug Holloway, director of parks and recreation, in a Tuesday news release. “The investment to protect the animals and zoo property is a good one, given the circumstances.”

The flood barrier will close Julia Davis Drive from the Gene Harris Bandshell to the tennis courts east of the zoo. Friendship Bridge between the park and the Boise State University campus will remain open, though the Greenbelt remains closed due to safety concerns.

Hobbs said weather forecasts for the next 10 days offer a bit of optimism — by the end of that period, the amount of water flowing into upstream reservoirs should be less than the amount flowing out, Hobbs said, allowing for a bit more space in the reservoirs.

  Comments