Ancient river still runs wild

March 13, 2005

JOEL DAVIDSON/Frontiersman reporter

MAT-SU - Land owners in Circle View Estates should breathe a little easier this summer when warmer temperatures cause the notorious Matanuska River to swell and tear into surrounding riverbank.

Despite the construction of four finger dikes, which are meant to divert the powerful river, riverside residents each summer watch land crumble into the water. Over the past 10 years, whole homes have washed away.

The Mat-Su Borough is hoping to stem the tide, beginning this spring by repairing the four dikes adjacent to Circle View Estates. On Tuesday, the borough Assembly awarded a contract to John Psenak Construction to begin repair work as soon as possible.

With spring breakup fast approaching, however, time is of the essence. In past years, work on the dikes has been hampered by high water levels.

According to Borough Manager John Duffy, when the dikes were originally constructed, nearly 10 years ago, the borough was under a lot of pressure to build them quickly to save fast-eroding property.

"They were constructed in high water and were not able to be built correctly," he said. "We weren't able to dig into the bottom of the river, and because they weren't built properly, they were subject to a lot more wear."

Duffy said the borough wants to begin repairs right away but first must obtain necessary permits. Weight limits on roads this spring will also affect construction timelines.

Duffy said the borough hopes to have the dikes finished by mid to late May. Construction will stop in early summer when the state Department of Natural Resources notifies the borough that fish runs are occurring in the river.

If sufficient funds remain, a fifth dike will be constructed in the fall.

In November 2004, the U.S. Natural Resources Conservation Service published an extensive study on the Matanuska River, describing several alternatives for erosion control, including spur dikes and gravel extraction from the bottom of the river.

In theory, gravel extraction would alter the river's flow away from the threatened banks. Duffy said a more in-depth study is necessary, however, before the borough moves ahead with the gravel-extraction alternative.

"We don't know with any degree of specificity of where to mine the gravel," he said. "Depending on where you mine gravel, a couple of different things might happen. In some areas, it doesn't draw the water away from the banks."

Currently, the borough is seeking additional federal funds to allow NRCS to complete a more detailed study of gravel extraction and trench proposals. In the meantime, the borough is applying for gravel-extraction leases from the Alaska Department of Natural Resources, so extraction can move forward once studies are completed.

Complaints about river erosion go back to the first colonist that moved to the Valley 70 years ago.

Duffy said he doesn't think the battle with the river will ever completely end. One plan, however, is to map the areas along the river that are high risk for erosion.

To that end, the borough is asking Alaska's congressional delegation in Washington to help procure funds for identifying and mapping erosion zones.

"Where would it occur in the next 50 or 75 years?" Duffy said.

If there were some way to predict erosion, then the borough could come up with development guidelines, Duffy said.

"We will take a look at development guidelines," he said. "What you can do that makes sense and what you can do to protect yourself."

Contact Joel Davidson at joel.davidson@frontiersman.com.