Updated  9:15 a.m.: The Moose Creek Dam was activated this morning to restrict the flow of water through downtown Fairbanks. It's the first time in six years the flood control project has been activated.

 Flooding continues in the Chena, Chatanika and Salcha rivers. Some roads in Two Rivers flooded overnight and are impassible.

Water is still running across Chena Hot Springs Road at 36.9 Mile and may be impassible for some vehicles. Caution is urged. The Chena River is also carrying a significant load of sticks and debris, according to the National Weather Service. 

More rain is expected today. Another 1/2 inch could fall over the region before clearing on Sunday.

FAIRBANKS - Their vegetable garden was completely under water at their cabin 25 miles up the Salcha River on Friday, but things could have been worse for Dick and Kayd Johnson.

At least their hot tub was still in the yard. Granted, it wasn't where it was supposed to be, having been floated a couple hundred feet across the yard by high water, but it was still there.

"We watched one float down the river and wondered whose it was," Kayd Johnson said by cell phone on Thursday. "At least we didn't see any outhouses floating by this time."

High water on the Salcha River is nothing new for the Johnsons, who are in their 70s and have owned their cabin for 35 years and now live there year round. But this time it was more serious than most, Kayd Johnson said.

"We've had high water many times but this doesn't happen very often," Kayd Johnson said. "We still have about 26 1/2 inches of water covering our whole yard.

"We usually have high spots sticking up around the yard but this time there's nothing," she said. "My garden is totally under water."

The last time she remembers the water being that high was in August of 1986, Johnson said.

Fueled by three days of heavy rain, rivers in the central Tanana Valley continued to swell on Friday, causing minor flooding on the Chena, Goodpaster and Salcha rivers . More serious flooding could occur in residential areas when rivers crest sometime Saturday, according to the National Weather Service.

"The crests are moving downriver right now," said Ed Plumb, a hydrologist at the weather service in Fairbanks.  Both the Chena and Salcha rivers were expected to crest in the lower portions sometime late Saturday night, he said.

Between 3 and 4 inches of rain fell in the upper Chena and Salcha river basins from Tuesday to Thursday as the result of a low-pressure system from the Gulf of Alaska that was parked over the central Interior for three days. The rain caused rivers and streams that had been running extremely low up to that point to swell to flood stage.

More than a foot of water was flowing over Chena Hot Springs Road at 36.9 Mile in the Chena River State Recreation Area east of Fairbanks, but the road was not closed, said Department of Transportation spokeswoman Meadow Bailey. DOT was advising motorists to "use caution and travel at their own discretion."

The flood gates at the Moose Creek Dam at the Chena Flood Control Project in North Pole had not been lowered to restrict flow as of 3 p.m., but project manager Tim Feavel said the gates would likely be lowered sometime Friday afternoon or evening. The water flow at the dam was 7,000 cubic feet per second at  around 2 p.m. and the gates aren't lowered until the water flow reaches 8,000 cfs, he said.

When the flood gates are lowered, it would mark the first time in almost six years the water in the Chena River has been high enough to cause the flood gates to be lowered, Feavel said.

A substantial amount of debris that was washed down the river has built up behind the dam, and Feavel expects more to follow in the next 24 hours. The weather service is predicting the Chena River will crest at the dam sometime late Saturday night, he said.

The upper Chena River appeared to be cresting at Granite Tors near 39 Mile Chena Hot Springs Road at around 11 a.m., but weather service officials weren't expecting that crest to reach the flood control project in North Pole until late Saturday night.

A river gauge at the dam measured the river at 23.2 feet at 10 a.m. Friday and the river was expected to rise to 25.0 feet later in the afternoon and remain there through Sunday. Even with the flood gates lowered to restrict flow in North Pole, there's a good chance low-lying areas below the dam will flood as a result of water coming over the banks, Plumb said.. The weather service issued a flood advisory for residents in one flood-prone neighborhood, the Steamboat Landing Subdivision on Freeman Road, and said water may inundate yards and portions of the road.

 "Even with (Chena Flood Control Project) regulating there's going to be enough water to cause some nuisance flooding," Plumb said.

Several spots in the Chena River State Recreation Area were flooded on the upper Chena River on Friday, including the Compeau Trail trailhead at 29.9 Mile, the shooting range at 36.5 Mile, and the Granite Tors campground at Mile 39, Plumb said.

The Salcha River crested at the Johnsons' cabin, which is about 25 miles upstream from the Richardson Highway, at around 10 a.m. on Friday, Kayd Johnson said.

In addition to floating their hot tub and attached deck across the yard, the high water also floated the Johnson's greenhouse a couple feet across the yard.

But Kayd Johnson said that was the extent of their problems. Their cabin and other structures are all built on pilings.

"We made sure we built everything up high," she said. "We don't have any water in any buildings.

"All we did was make sure to move our boat into position so debris wouldn't damage it," Johnson said.

Their cabin is higher up on the riverbank than a lot of cabins on the Salcha River, which does not bode well for other cabin owners, she said.

"I'm sure there's other places that have it a lot worse than we do," Johnson said.

On the Goodpaster River, there was minor flooding reported at the Pogo gold mine, which was expected, but the river crest was still making its way downstream on Friday. There are several private cabins on the lower reaches of the river that could be flooded, Plumb said.

While the rain tapered off in some areas late Thursday afternoon, a band of heavy showers moving east from Fairbanks and North Pole to the upper Chena Basin dumped another one-half to three-quarters of an inch of rain over that area Thursday night, Plumb said.

Fairbanks residents were given a reprieve from the rain on Friday but another low-pressure system is expected to move into the Tanana Valley from the west on Saturday and dump another one-quarter to one-half of an inch of rain, Plumb said.

"What that's going to do is slow the recession of the rivers as we get more rain in the Chena and Salcha basins," he said.

How much water will build up on the flood plain behind the Moose Creek Dam depends on how long the gates are kept down to regulate flow, Feavel said. He didn't expect it to be much, but that could change with more rain in the forecast.

Whatever the case, Feavel said lowering the flood gates for the first time in six years will be significant. The flood control project was built for this precise scenario, he said.

"This is good for us and it's good for the community, too," he said. "Everybody gets to see how we do it and it gives us an opportunity to test all of our phone trees, our hydrology section and our geotech guys."

Contact staff writer Tim Mowry at 459-7587. Follow him on Twitter: @FDNMoutdoors.

Rainfall totals

Here is a list of three-day rainfall totals as of 10 a.m. Friday provided by the National Weather Service for selected locations across the central Interior:

Goodpaster River — 4.61''

Chatanika — 3.61''

Salcha River (25 Mile) — 3.09''

Two Rivers — 2.95''

Fort Wainwright — 2.35''

Nenana — 2.17''

University of Alaska Fairbanks — 1.94''

Fairbanks International Airport — 1.60''