Story last updated at 2:33 p.m. Thursday, December 5, 2002

Floods present opportunity, challenge to science community
by Sepp Jannotta
Staff Writer

The head-scratching starts with the meteorologists. Then it moves to the hydrologists, biologists and the average Kenai Peninsula resident, who all probably guessed that by mid-November folks would be skiing, skating or snowmachining across a frozen Alaska landscape.

"I think we're struggling with the fact that the lower peninsula is changing."

<> Sue Mauger, biologist

What are the chances of a once-in-a-century flood unleashing so late in the year? And how about the odds that such an epic washout would be followed a month later by a near-carbon copy?

Whatever the odds, the bizarre weather has wrought visible and measurable changes to the lower peninsula's rivers and creeks and the surrounding landscapes.

During both flood events, motorists driving between Anchor Point and Homer and along East End Road were painfully aware of where the rivers and mud flows had compromised the roadways. Many area homeowners dealt with property damage that was more than just a passing inconvenience, as muddy flash floods slammed into houses.

But for the science community, witnessing a pair of once-in-a-lifetime floods unleashed in a one-month period is a tremendous opportunity to add to the pool of data on area watersheds.

"We do get excited about this stuff," U.S. Geological Survey hydrologist David Meyer said after the Nov. 23 storm.

As if rising rivers weren't excitement enough, the U.S.G.S., which typically operates three gauging stations on the lower peninsula, lost its equipment on the Anchor River when flood waters Nov. 23 washed away the gauge's housing at the Sterling Highway bridge near Black Water Bend. That site had provided the best data from the Oct. 23 flood because the Ninilchik River gauge was damaged by a heavy-duty excavator trying to save one of the village's bridges.

Still the two instruments, which relay flood stage information to Anchorage -- by phone modem in the case of the Anchor River and by satellite at Ninilchik -- provided U.S.G.S. hydrologists with some impressive numbers.

The estimated peak flow during the October flooding on the Anchor River was around 10,000 cubic feet per second and was estimated at 17,000 cfs below the North Fork confluence.

With solid data compiled for more than 25 years, Meyer said, U.S.G.S. can calculate roughly what the high water mark would have been over the past 100 years.

"These are bigger than anything we've seen, obviously," Meyer said. "And they are probably bigger than a 100-year flood on Fritz Creek and the Anchor River."

Data for the Ninilchik River and Deep Creek was not as reliable, though estimates for the Ninilchik River were also off the charts, he said.

According to National Weather Service river forecaster Ben Balk, having two consecutive off-the-charts floods during the past month says less about remarkable timing and more about a larger weather event.

"At this point it's probably less about having two 100-year floods," Balk said. "The reality is that we may just be locked into a 100-year weather pattern."

If you're feeling like the lower Kenai Peninsula has been victim of some bizarre meteorological experiment, you may not be far off, according to some regional weather experts. The storm pattern, known as the pineapple express -- a Bering Sea low pressure system and a western Canada high combine to funnel warm moist air up toward Southcentral Alaska from the Hawaiian Islands -- is common enough during the winter months. But the strength and duration of this year's pattern is what seems to be unusual, meteorologists say.

A record high temperature of 55 degrees at Ted Stevens International Airport on Nov. 26 made headlines in Anchorage, as the city charted its warmest November on record.

According to Balk, from Sept. 26 through Nov. 26, the average temperature in Anchorage was 39 degrees, by far the warmest for that period since record-keeping began in 1925.

Balk said there has been a lot of speculation over the fact that so much rain has been falling on the lee side of the Kenai Range. Typically, the outer coast and Prince William Sound side of the peninsula absorb the lion's share of the rainfall, with the Kenai Range casting a rain shadow over Homer and the area to the north.

Balk said this trend will likely be the focus of concerted study by the regional office of the National Weather Service.

But during both of the recent storms, there was an unusual amount of rainfall in the region of the Caribou Hills, northeast of Homer.

What followed was a torrent that overran the capacities of the area's drainages, stripping away stream banks, toppling trees, carving new river channels and wiping out nearly every man-made object in its path, including roads, bridges, vehicles and cabins.

It is the swirling waters of the chocolate-colored flood that interest watershed biologist Sue Mauger, coordinator of a water quality assessment project for the lower peninsula salmon streams sponsored by Cook Inlet Keeper and the Homer Soil and Water Conservation District.

The study's findings were released only weeks before the October floods roared out of the hills.

Armed with four years of data from the Anchor River, Deep Creek, Ninilchik River and Stariski Creek, Mauger went out the following week and set about checking what the flood waters had stirred up at some of her 12 different sites. Mauger assessed the general health of each stream by measuring the stream flow, temperature, oxygen levels, pH levels, conductivity and levels of key indicator chemical compounds such as nitrates and phosphorus. Data is recorded on turbidity, or water clarity, the amount of dissolved and undissolved solids in the water and the kinds of bacteria present.

With the water still roiling after the unprecedented high levels, the measurements taken in the days following the first flood were astounding, Mauger said.

She found levels of phosphorous that were three times higher than any previously recorded.

Nearly all her water quality indicator test results were off the charts.

While the long-term implications of such major flooding events for watershed health isn't crystal clear, Mauger said the collection of data from such an extreme event is enormously valuable.

"I think we are struggling with the fact that the lower peninsula is changing," she said. "So it's difficult to know if that is natural variability or not.

"It's not something that we'll be able to pull out of a five-year study, but I think this (information) will be extremely valuable in 10 to 12 years."

Nonetheless, Mauger said the level of sediments she measured in the streams, most notably in Deep Creek, following the floods raises concern over the effects of the ever increasing logging and road development in the streams' upper reaches. "Unfortunately, sediment is one of the biggest concerns for (salmon) viability at all stages of life," Mauger said. "I would hate to see our streams go the way of the Oregon salmon streams."

Sepp Jannotta can be reached at sjannotta@homernews.com.

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