It’s a bold plan to stop the Sandy River’s wandering ways

FARMINGTON – It’s just five more days until a state permit can be issued to try and stop the Sandy River’s destructive forces as it continues to take big chunks of a steep embankment that is threatening the Whittier Road above it.

That’s the good news.

The bad news is that although the emergency mitigation plan – a bold one at that – is expected to be approved by the state’s Department of Environmental Protection on or soon after Dec. 9, another tedious waiting period may be in store due to winter’s imminent arrival and the question of paying for it.

The two-pronged plan calls for some excavation of a large sand bar opposite the eroding trouble spot and to stabilize the bank in what will be the largest soft armoring project of its kind in Maine.

Fifty feet of steep embankment near the intersection of Whittier Road and Route 156 in Farmington Falls collapsed into the river after tropical storm Irene and the following week’s intense rain storm swept through in late August.

In late October environmental consultant Rick Jones of Jones Association was given the go-ahead by Farmington selectmen to secure the state permitting necessary for the stabilization of the river bank and for removal of sand from the so-called Pillsbury bar that sits across from the eroded area.

The plan to stall and hopefully reverse the river’s erosive progress towards the well-traveled road by partial sand bar excavation is a return to a practice banned a decade ago. At the same time, the new practice of embedding mature tree root balls anchored with boulders in trenches dug 12 feet into the side of the bank to fend off the river’s advance are also in the plans. This root ball strategy has never been tried on this scale before in Maine, Jones said.

The river’s natural forces are nothing new to University of Maine at Farmington’s associate professor of geology, Dr. Julia Daly. She and senior student-intern Abby Berlin have completed the latest ground penetrating radar studies on the Pillsbury bar. A recent flight over the river, from New Sharon to Phillips, provided updated bird’s eye view photographs of the river and it’s ever changing, troublesome sand and gravel bars.

The data UMF has collected over the years has been important toward understanding how the Pillsbury and other sand bar formations move, change the river’s course and all to often result in loss of valuable property.

Before heading out to the Pillsbury bar with Jones late last week, Daly and Berlin unrolled a chart created from a recent  ground penetration radar survey of the sand bar that detects changes in sand grain size and water content to find its overall depth.

“The sand bar is about two-and-a-half meters (8.2 feet) deep,” Daly said pointing to the bar’s chart that looks like a child’s ant farm’s cross section.

Walking out onto the sand bar, Jones marveled at the change in height and shape of it since he visited the spot just two weeks ago.

“This is common on the Sandy River; it’s always in flux,” he said looking around. Pointing across the river he noted more of the vertical face of the embankment has been lost, too. The bank’s collapse is marching ever closer to the road. Above it, a yellow warning tape has been strung across the wide expanse by the Farmington Highway Department, along with traffic cones set along the road’s edge to warn of the steep drop off.

Evident, too, as the Department of Transportation works to complete a road rebuild and paving project on Route 156 next to the river, is that years ago large rocks were poured down along that road in an attempt to stop the river’s erosion aimed toward the road’s structure. The piles of rocks extend along Route 156 and stop at the intersection of the town-maintained Whittier Road.

“Years ago DOT apparently saw a potential problem here,” Jones said, adding that the rock piling was probably completed many years ago before permitting would have prohibited the practice these days.

The plan is to install the root balls along the entire stretch of the banking collapse and beyond it in a line above the normal high water mark of the river. The root balls, angled toward the current, have been found to not only protect the banking from further erosion, but if all goes well, they’ll catch silt and rebuild the bank over time. Once installed, the root wads will be planted with silver maples and dogwoods to help anchor and hold the bank for years to come.

An underlying culprit in all this is the Pillsbury sand bar that has grown out into the river and has forced the water flow into the opposite banking. The growing bar has also narrowed the river causing its flow to speed up considerably. Jones said at the bank’s worse point of erosion, he’s found a 14-foot deep hole that also acts to push the river’s velocity even more. Faster water packs a much bigger erosive punch.

“If we did nothing the sandbar would be at the road’s shoulder in no time,” Jones predicted.

The excavation of the sand bar is a return to a practice banned beginning in the 1990s.

If the permit is approved, which Jones is optimistic it will be, his plans call for excavating a channel across the back of the Pillsbury sand bar, two to four feet in depth. Offering the river an alternative route will act as a pressure reliever at the river’s crucial bend. The permit is expected to be good for a period of two or three years, so excavation can continue as sand moves in towards refilling the channel, as nature seems to demand.

“Hopefully, the town can come in and work quick as they can after the permit is approved,” Jones said.

Farmington Town Manager Richard Davis said he understands the need to move as quickly possible, but that may not be possible due to weather and funding constraints.

“The removal of the sand bar can be done right away; there are no major costs involved,” Davis said. The root ball installation, however, which the town wants to do to save money, if possible, will probably end up being expensive. Davis guessed it could cost any where from $50,000 to $100,000 to do the work.

It’s a complicated job, the costs are as unknown now as is how it will be funded, Davis said. He’s hoping that Emergency Management Agency grant funding might come to the rescue to help with the cost of the work. If that fails, voters may be asked to approve funding for the project.

Davis and Highway Department director Denis Castonguay will be exploring options, including who should do the work and how to pay for it this week.

Having to look for funding for the project is somewhat of an irony to Jones. He noted, “if we did nothing and then the road collapsed, MEMA and/or FEMA would pay for it through its disaster funding.” By installing root wads, the town is looking at the most cost effective method to save the bank, the road and much higher costs, Jones added.

“The town is acting very proactively and will in the end save the hundreds of thousands of dollars it would take to rebuild the road if that should happen,” Jones said.

For Daly, the sand bar excavation coupled with a root ball stabilization strategy makes for an interesting living laboratory for her students. UMF’s geology department, particularly Professor Tom Eastler, has been surveying the Sandy River and its changing sand bars for years. Eastler is a proponent for the return of mining gravel as a way of keeping the river in its current banks.

People who have built roads, houses and pastures along the river are at some point in for a rude awakening. Daly said it’s the river’s natural tendency to want to meander that causes problems for those structures  too close to the river. Jones agrees and said when he sees a farmer cutting down trees along a river at the edge of a pasture because the shade isn’t good for his sun-loving crops, he sees now what a problem the farmer will see in the years to come: loss of land. Valuable, fertile pastureland, bordering along a river will erode away without its vegetation to hold it there, he said.

Daly said she is not surprised by the river’s changing ways after the flyover.

“We’re seeing really consistent changes,” she said after viewing sand bars from Farmington Falls to Phillips. Of particular interest will be to see what happens after the bank stabilization and excavation work on the Pillsbury bar, she added.

“We’ll be looking at it over the next couple of years to track how things are responding,” Daly said. “We’ll be able to provide numbers where no one else is.”