By Dr. Robert Thorson
Beware the serpent. This is a biblical injunction to avoid reptiles without limbs.
Beware the serpentine. This is my geological injunction to avoid building homes on the banks of meandering rivers, which writhe on their flood plains like snakes in the grass.
I refer to the tragic case of Pete and Sue Jones of Cromwell, whose home is about to fall into the meandering Connecticut River. Their plight was the front-page, centerpiece story for The Courant on July 7. Included was an amazing photo showing disaster in the making and a complicated expression on Pete’s face.
I suspect that his look comes from 15 years of befuddlement and frustration. He’s talked to nearly everyone: the state Department of Environmental Protection, the Army Corps of Engineers, the National Resource Conservation Service, the town of Cromwell, other agencies and finally the press. Also in his expression is resignation: His dream domicile will soon be gone.
“Pete contends that his house should never have been built, that his breathtaking river view is inherently dangerous,” according to the story.
I agree. The compromise between breathtaking views and breath-ending slope failures is a familiar part of the geological hazards curriculum. Engineering studies to confirm the precise mechanisms of slope failure would be expensive. Solutions, if possible, would almost certainly cost more than the house is worth, affect other parts of the river and require permits from enmeshed bureaucracies.
By the time Pete navigated multiple agencies for a permit to fix his problem, his house would probably be gone, based on the current rate of erosion.
And who would pay for the solution should he get the permit in time? Insurance? No: there are loopholes. State and federal support? No: Funds would be available only if dozens of homeowners were similarly affected, or if the home was hit by a discrete event such as a storm.
The previous owners? They probably spotted the problem before selling to Pete and Sue in 1992, but are no longer responsible. The town of Cromwell? It approved the building plans in 1982 without any mention of the hazard, but officials can always plead ignorance.
I find it amazing that bank erosion by the Connecticut River is made out to be so dramatic and mysterious. Early settlers of the Connecticut River Valley took seasonal flooding, river migration and sediment transport in stride. In 1806, a congregational minister named David McLure from East Windsor – hardly an engineering expert – wrote that the Connecticut River had migrated 50 rods in 75 years, for an average rate of 11 feet per year.
In 1884, a contractor named C.C. Goodrich dredged more than 10,000 cubic yards of sediment from the river’s channel at a single spot, nearly all of which came back the following year. This sediment came mostly from upstream bank erosion.
The U.S. Geological Survey mapped the channel of the lower Connecticut in 1890, and then again in the first half of the 20th century. Based on these maps, the average rate of bank migration at a variety of sites between Middletown and Hartford was about 3 feet per year. Migration at Pete’s house is one-third slower, in part because his house is above the flood plain.
During the past 50 years, the banks of the Connecticut River have been more stable because the great floods of mid-century provoked a knee-jerk reaction from politicians and engineers. They did their best to make the snake stand still with massive engineering projects including levees, reservoirs and riprap. But much of the apparent stability is an illusion caused by a suburban detachment from perfectly natural processes.
No geologist I know would invest in a house built on the edge of a gravity slope composed of loose sand deposited above an impermeable layer next to a powerful river. This observation, which can be made from the text and photos of the article alone, was confirmed by a quick look at excellent and widely available geological maps compiled by state and federal agencies.
How sad. In the sport called land-use planning, private interests and public safety compete against each other in full view. Unnoticed on the sidelines and squelched by the political process are scientists who weep.