The gnarled mass of root-wads, rocks and logs where Bear Creek meets the Rogue River looks more like a pile of slash ready for burning than a carefully constructed buffer protecting one piece of nature from another.

The gnarled mass of root-wads, rocks and logs where Bear Creek meets the Rogue River looks more like a pile of slash ready for burning than a carefully constructed buffer protecting one piece of nature from another.

Eugene Wier picks his way carefully through it Tuesday as he treads where Bear Creek roiled five days ago when the winter's first significant rainstorm challenged this buffer's ability to curb erosion of banks exposed by the removal of Gold Ray Dam from the Rogue in 2010.

He likes what he sees.

"The flows put it to the test," says Wier, a natural resources technician for the Rogue Valley Council of Governments. "It's doing exactly what it's supposed to."

Halfway into the second winter since these banks saw air for the first time in 106 years, the engineered Bear Creek mouth — fortified to help keep the Rogue and Bear Creek in their channels — is getting good marks for toughness.

The structure now has taken two stiff jabs from small storm events almost exactly one year apart, with the most recent coming Thursday when flows peaked at what was a pretty run-of-the-mill level for the Upper Rogue River Basin.

But the rock, wood and gravel structures have yet to take one of nature's haymakers in the form of a significant flood event — one that will reveal whether the new-look creek mouth can really take a punch.

"Things aren't looking too bad right now, but we still haven't had a major test," says the RVCOG's Craig Tuss, who is overseeing rehabilitation efforts of stream banks exposed by the dam's removal.

"I'd say the jury is still out on how the creek mouth might change from a major storm," Tuss says.

Efforts to restore banks that have been underwater since the Teddy Roosevelt administration are halfway through a three-year program to turn what once was the bottom of Gold Ray reservoir into a free-flowing river.

In its day, the dam backed up water into two sloughs and in the main-stem Rogue up past the mouth of Bear Creek. The lower 1,000 feet of Bear Creek was like a stagnant extension of the reservoir.

The dam's demolition dropped lower Bear Creek by 5 feet and other downstream banks on the Rogue as much as 20 feet, leaving the vegetation line far from the water.

Perhaps the most tenuous piece of newly exposed dirt was on the south side of Bear Creek's mouth. High Rogue storm flows threatened to pound into it, and the soft bank, which had little vegetation at the time, had a strong chance of failing if left alone.

Armed with a $507,000 NOAA-Fisheries grant and some money left over from the federal stimulus grant used for dam removal, the Corvallis-based River Design Group went to work.

Computer models helped design a new meander channel for Bear Creek through the newly exposed stream bank. Specific-sized rocks were placed in the lower creek to absorb some of the energy of the rushing waters.

But the big bang came from root-wads and timbers — many salvaged from the original timber-crib Gold Ray Dam — that were dug into the banks to strengthen loose soils ready for planting.

Since then, the RVCOG and local organizers have marshaled volunteers to plant thousands of native plants and willow shoots whose roots over time will give the banks greater strength to withstand storm runoff.

"Bear Creek's looking pretty good," says Scott Wright, River Design Group's chief designer on the project. "It's got a nice pool-riffle sequence.

"Things will only get better in time if we get more vegetation growth."

Until then, all eyes are on the Bear Creek mouth every time the river rises.

The first test came Jan. 16, 2011, when storms swelled the creek and the Rogue peaked at about 18,000 cubic feet per second at the mouth. That's the kind of winter storm that statistically can be expected every other year — not huge, but a good first test.

It passed.

Last week's storm peaked at about 12,600 cfs there late Thursday, and all the main structures are still in place.

"Think about how much pressure this thing has taken, and it looks great," Wier says.

Reach reporter Mark Freeman at 541-776-4470, or email at mfreeman@mailtribune.com.