The waiting game

Leroy Duroux knows what it’s like to worry about flooding on a macro and micro level.

As mayor of Basalt, he has concerns about the general welfare of a town that sits at the confluence of two major rivers. But his most immediate concern is for his neighbors.

Duroux lives in River Oaks, a subdivision where million-dollar homes line the Roaring Fork River. On a tour last week, he pointed out the remnants of sandbags that were piled 3 feet high in the yards of some of the homes in 1995, the last time major flooding posed a threat in the Roaring Fork Valley.

He recalled that one newcomer to the subdivision back then called him at midnight in a quasi-panic because the water was lapping at his back patio. Duroux headed a sandbag brigade that shored up the defenses of the lowest lying lots. No homes were flooded.

River Oaks has more homes now, about eight within a stone’s throw from the river. Duroux is convinced the newcomers don’t realize what could happen since runoff has been so pitiful in most recent years. The homeowners association has purchased and stockpiled 1,000 sandbags and is making arrangements to have sand or gravel road base delivered to their cul de sac.

<b>Be prepared</b>

As a lifelong valley resident and as mayor of Basalt, Duroux is advising other homeowners who are potentially in harm’s way to do the same.

“My philosophy is take care of yourself and be prepared because you’re not going to be able to rely on anyone else,” he said.

That’s sage advice, said Scott Thompson, Basalt’s fire chief and a member of the Incident Management Group that’s been organized by government and emergency responders in Pitkin County. “It’s all about preparation,” he said.

If flooding occurs, emergency response teams will have their hands full protecting and monitoring public utilities and facilities — everything from Basalt’s sewage treatment plant to exposed power poles. Homeowners will, out of necessity, be on their own.

Thompson was in the unenviable position earlier this month of explaining that to about 75 residents who live in two trailer parks in the heart of Basalt. The meeting attendees, mostly Latinos who didn’t live there in 1995, seemed apprehensive and uncertain about what to expect. Thompson’s words of warning were translated into Spanish.

“You shouldn’t be scared yet. Maybe in May,” he told them.

<b>The waiting game</b>

That’s the best advice anyone can offer at this point. A big snowpack usually translates into high runoff, noted Rick Lofaro, executive director of the Roaring Fork Conservancy, a Basalt-based nonprofit that monitors watershed issues. The Roaring Fork basin certainly has a high snowpack; as of March 21, it was 47 percent above average for that date.

But Lofaro noted a lot can happen between now and early June, when the Roaring Fork River typically peaks. Those factors can affect how quickly the snow melts and the consequences. Duroux agreed. It’s too early to start throwing sandbags around houses just yet, he said.

Two federal agencies have provided preliminary forecasts that measure runoff in different ways. The Natural Resources Conservation Service, the same agency that measures snowpack, forecasts streamflows.

The agency’s preliminary projection is that the Roaring Fork River will move about 40 percent more volume of water than average during the runoff season between late April and the end of July this year.

The runoff volume flowing into Ruedi Reservoir is expected to be 30 percent above average.

<b>Peak runoff could be big</b>

The agency is pretty confident of that forecast based on snowpack levels, said Mike Gillespie, snow survey supervisor. The snowpack usually builds to its peak by April 14 in Colorado’s central mountains, he said. This year, the March 1 snowpack level was already above the average peak.

And it’s still snowing. Unlike recent years when warm, dry weather in March ate into the snowpack, cool and wet weather is maintaining the snow depth this year.

If the snowpack remains 47 percent above average into the warm weather months of May and June, the peak runoff could be big.

The National Weather Service’s Colorado Basin River Forecast Center made its initial peak runoff forecasts during the first week of March. Rather than volume, it’s forecasting the temporarily spike the river will achieve, probably in early to mid-June.

The “most probable” peak for the Roaring Fork River at Glenwood Springs is 8,500 cubic feet per second, the agency said. The average peak is 6,150 cfs. In other words, this year’s peak could be 38 percent higher than average.

The good news for property owners is that would still be below flood stage. The forecast center considers the flood flow to be 11,800 cfs at Glenwood Springs. No data is available for the forecasted peak or the flood flow at Basalt or Aspen.

The forecast center said there is a 25 percent chance the Roaring Fork River’s peak at Glenwood could exceed flood flow. Perhaps most alarming is the 10 percent chance the peak will exceed 15,000 cfs.

<b>Rainy spring, frazzled nerves</b>

Gillespie said the best-case scenario would be experiencing weather that spreads out the runoff. Short periods of warm weather separated by cold streaks would be ideal. Cold weather up to the end of May followed by warm temperatures could cause problems.

Duroux recalled that rainy weather caused problems in June 1995. Rainstorms accelerated the amount of water rushing down the river. Unfortunately for downvalley residents, the results of warm days at the headwaters above Aspen don’t show up until night. It takes time for water surges to flow downstream.

He recalled standing on the shoulder of Two Rivers Road with other members of the Basalt Town Council checking out the flow of the Roaring Fork one June evening in 1995.

Overnight, the river ate away the bank and gobbled the road to the center line.

The Pan & Fork Mobile Home Park and the Roaring Fork Mobile Home Park, the homes for about 90 families combined, were protected by makeshift dikes along the river, but swamped by up to a foot of groundwater.

Adrianna, a Latina resident of the Pan & Fork, attended the meeting recently where Thompson shared expectations and preparation tips for the runoff season. She was relieved to hear that authorities will watch river levels at night and warn residents if they need to evacuate.

While the meeting removed some of the uncertainty, it also gave her more of an idea about the potential threat. “I feel better, but I’m scared now,” she said.

<b>Smaller threats loom</b>

Thompson said high river levels aren’t the only potential threat. “Just a simple clogged culvert” can create problems, he said. For example, there are 13 tributaries of the Fryingpan River between Basalt and Ruedi Reservoir dam. Culverts could easily be jammed by tree limbs and debris, forcing fast-moving water over the road.

“That can take a road out quick,” Thompson said.

A clogged irrigation ditch overflowed and sent water and mud cascading into some Elk Run homes one recent summer, pointing out another type of potential problem.

But Thompson said the area at and below the confluence of the Roaring Fork River and Fryingpan River in Basalt remains his top concern. “Historically that’s where we’ve had problems.”

He is advising homeowners who live in potentially affected areas to play it safe and shop for flood insurance.

The Colorado Department of Transportation also plans to play it safe. The agency has applied for a permit from the U.S. Army Corps of Engineers to dredge material under and upstream of the east Basalt Bypass Bridge on Highway 82.

The transportation department wants to remove 1,500 cubic yards of sand and rock to improve the flow of water. That’s the equivalent of 150 dump trucks.

Thompson said local agencies would welcome the project. Better flow will prevent the river from slamming water into a levee on the outside bank of a curve heading into that bridge. If water breached that levee, it would flow into the Southside subdivision.

“If that gets dredged, that will take a lot of pressure off Southside,” Thompson said.

scondon@aspentimes.com