As runoff flows, city keeping a close eye on Cedar Creek Reservoir

While most eyes are on the Flathead River as water levels rise, the city of Columbia Falls is keeping an eye on its own dam — the Cedar Creek Dam north of town.

The city doesn’t use the water supply behind the earthen dam anymore, but it does control the structure. The water levels in the dam are rising and water is running through the diversion ditch at close to full capacity.

The ditch runs from the dam through the Columbia Falls Aluminum Co. plant property and runs the water directly into the Flathead River, city public works Director Grady Jenkins told city council Monday night.

The city has another option to release water into Crystal Creek. The creek winds down through the woods from the dam and flows behind the industrial park on Railroad Street.

It then goes underground. But in wet years, the water flows back up to the surface where the high school softball fields are now and in what is now the Scenic Point subdivision.

As such, the city is avoiding releasing much water into the creek. Jenkins said they did an experiment last week by releasing some water into the creek, which lowered the water in the diversion ditch, which was just inches from the top. There was no flooding from that.

The earthen dam has a built-in emergency bypass. If the water gets too high, it will flow through the bypass. However, if that happens, it would likely flood the CFAC property as well as the Aluminum City neighborhood.

The water would have to rise significantly for that to happen. In addition, the city has concerns about the Flathead River itself. Aside from flooding homes, it could inundate the city’s sewage lift station at the end of South Nucleus. Public works staff are keeping on eye on that as well.

The Flathead River at Columbia Falls was projected to reach 13.7 feet by Thursday, which is just above minor flood stage, though it should drop by week’s end.