newsminer.com

With the month of August almost half over today, it would be appropriate to breathe a quiet word of thanks for the flood control project that gives Fairbanks and North Pole area property owners a thin, but so-far-effective, line against disaster.

While nearby areas such as Nenana saw serious flooding due to the high water in the Tanana River, Fairbanks was largely spared damage.

Despite the seemingly endless rain this summer, the flood control gates weren’t used to restrict the Chena River’s flow nearly as much as has been necessary in the past. Previous diversions backed vast amounts of water into the cleared channels and forested areas between North Pole and Moose Creek bluff.

But the gates were used — for the 20th time in 27 years — much to the relief of everyone living and working near the river. The Chena rose right to the top of the banks in central Fairbanks, providing plenty of tension even with the system of gates, dams and diversion channels upstream.

Some folks are also aware that the Little Chena River dumps into the main Chena below the flood control gates. The Little Chena gauges are monitored, but an unusually fast and large slug of water from that source could challenge the system.

The tension was even thicker on the lower Chena during the recent rains because the protection wasn’t so certain there. The Tanana River ran at near-record levels, which backed the lower Chena up well above its banks in places. And suburbs such as Rosie Creek, downstream of Fairbanks, and Salcha, upstream of Fairbanks, are outside the zone protected by the Chena project, so they were swamped by the Tanana.

The flood control gates, operated by the U.S. Army Corps of Engineers, must be employed cautiously because impounded water can also impound fish. Test nets set by researchers during previous floods have turned up grayling far out in the woods. And the Chena is an important salmon spawning river.

The corps also must act conservatively because previous, lengthy impoundments apparently caused groundwater levels to rise in areas downstream from the dam, flooding basements.

Despite its limitations, it’s nice to know that thin line upstream is functioning well as we look toward another two weeks of August, normally the wettest month of the year.