Sinking Homes in Amherst, NY

The Town of Amherst, NY, has over 1,000 homes with foundation problems. The US Army Corps of Engineers completed a study of the expansive soils there.

A clay soil found throughout north Amherst may be causing a "dome" effect under some homes, pushing up the centers of basement floors and allowing the walls and edges of foundations to sink, a U.S. Army Corps of Engineers study team has found. The clay is often found in a layer above a second type of clay that is so soft it's been dubbed "peanut butter."

Together, these two soils have been linked to much of the structural damage plaguing Amherst homes in recent years, the team is expected to report next month in a long-awaited $500,000 federal study of Amherst's sinking homes.

Nearly 1,100 homes have been affected by foundation damage over the past 20 years, or about 3 percent of all Amherst homes, according to a preliminary report. But damage rates may be 10 times greater in some affected neighborhoods, the study found.

About 55 percent of the homes in the study had lateral damage, which causes basement walls to bow or buckle inward. The remaining 45 percent showed signs of sinking.

Four types of pressure on basement walls are believed to be causing the lateral damage, including the pressures exerted by frost, soil weight, water in the soils, and soils that swell, according to Bradley E. Guay, technical manager of the study.

"Three of those are not typically accounted for in foundation designs," said Guay,who commented on the soil issues during a meeting Wednesday night of the Buffalo Association of Professional Geologists.

The two problem soils are spread across most of the northern half of Amherst, where builders are developing subdivisions for hundreds of new homes.

The findings could also affect future foundation designs. A preliminary draft of the report notes that laboratory tests show the stiff clay has a "medium to high potential" to swell or shrink depending upon its moisture content.

How does the dome form? According to the study team, differing moisture conditions below the basement floor and the perimeter footings of homes are suspected as one cause.

Perimeter drainage systems installed near the footings of most houses help to prevent water from settling and seeping into basements. But they also are believed to cause soils to dry out and consolidate.

And, because most homes do not have drains under their basement floors, water appears to collect below the centers of foundations, the study team indicated.

These differences in soil moisture could cause the ground to swell under the center of basements and to dry out and consolidate near the perimeter, causing foundations to sink, the study team believes.

The finding helps to explain why basement floors are heaving under some Amherst homes while their basement walls are sinking, Guay said. Samples taken from some of these homes confirmed that soils were drier under the foundation walls and more moist under the centers of basement floors in some of the homes studied.

In addition to the dome effect, the shrink-swell tendency may cause some parts of a foundation to fail, or what the study team calls "differential movements" of the house, during soil moisture changes.

Amherst has a mapping program on the town's web site to generate maps of specific features defined by the user.

Turn time back 11,500 years and look down on Western New York. Then more slowly wind forward again perhaps a hundred years at a time. You'll see the last of the half-mile-thick Wisconsonian ice sheet retreat through the area.

First the melting glacier will create Lake Iroquois, the beginning of what will later become Lake Ontario. But then, as the glacier backs further to the north and the water level drops, a smaller lake will form between two east-west ridges, the Niagara Escarpment and the Onondaga Escarpment. That long, shallow pond, rarely more than 30 feet deep and a few miles wide but extending all the way from Lewiston east to Holley, was Lake Tonawanda.

Everyone assumes they know the Niagara Escarpment. That's the cliff over which Niagara Falls drops. But what fewer of us understand is that it extends east and west from there as well. You can dine atop it at Schimschack's Restaurant in Pekin or follow it along the north edge of Lockport. The Onondaga Escarpment is less evident. One of its most obvious outcrops is in the Escarpment Sanctuary along Greiner Road in Clarence.

Lake Tonawanda pooled in the flat region between those two ridges roughly centered on what is now Tonawanda Creek between North Tonawanda and the Iroquois National Wildlife Refuge.

As your time machine continues to reel forward, you'll see that lake slowly dry up, leaving layer upon layer of oozy sediment, some of that soft admixture of sand, silt and clays still later turning into a kind of quicksand trap for homes later built in those wetland areas.

Homes in the towns of Amherst and the Tonawandas have been most in the news, with over 500 houses settling into this ooze and a state estimate of almost $5 million in damages so far. But other buildings located in the wetlands left by this Pleistocene lake may someday soon face similar difficulties.

Much has been reported about remediation of these serious current problems, but too little attention is being given to prevention of the same kind of disasters in the future.

Unfortunately, our state and local governments have failed us. New York, for example, is behind all the New England states in its definition of wetlands. Because of a 2001 Supreme Court ruling, the federal government now only protects wetlands connected to tidal, interstate and navigable water bodies. So-called "isolated wetlands," defined as those not so connected (and thus most of them), are now protected by New York only when they are 12.4 acres or greater or "of unusual local importance." No other state in the Northeast has a similar acreage requirement, and a national estimate indicates that between one-fifth and one-half of all wetlands are less than 12.4 acres.

Local builders and the municipalities that cater to them have taken advantage of such requirements to develop housing projects in areas with foreseeable problems and without notifying the home buyers.

Much to the credit of the Sierra Club and other conservation organizations, a bill (A7905-S4480) is working its way through the State Legislature to address this and other shortcomings in our wetlands protection laws. It has already passed the Assembly with only a single "No" vote recorded. The same conservationists, together with organizations like the Audubon Society, are pressing hard for Senate consideration and approval later this summer, when the Legislature meets in a special session.

This bill would afford protection to New York wetlands of at least one acre and regulate them if they meet the environmental criteria, regardless of whether they appear on a wetland map. So-called "grandfathering" of subdivisions that are not yet built, but that were proposed prior to 1975 to be developed in wetlands, will be eliminated. These are the loopholes in current laws that allow homes to be built in wetlands and sold to unsuspecting buyers.

Given the sad recent disclosures of legislative impropriety, our state representatives need to work to regain moral standing. Passing this bill to protect hundreds of future homeowners can represent a small but important step in that direction. Whether or not this bill makes it through this legislative session, it is most worthwhile, and I hope that it will eventually be signed into law by our governor.

NATURE WATCH - "The Woman Who Saw It Coming In Amherst"

The Buffalo News - 3/3/2003 - By GERRY RISING

Like Rodney Dangerfield, environmentalists "get no respect."

To consider an example, turn the calendar back to the 1980s.

During those years, Peggy Christensen wrote a column titled "Focal Points" for a suburban newspaper. Her column served as a beacon warning of the many problems being caused by overdevelopment in Amherst. Her writing drew upon the authority of such people as university geographer Charles Ebert, environmentalists Lester Milbrath and Bruce Kershner and Buffalo News reporters Dick Dawson, Mike Vogel, Lonnie Hudkins and Peter Simon.

Here are a few of her warnings:

* - "Builders like to develop wetlands because the land is cheaper than solid ground. This misuse causes many problems. Soil stability is poor, and buildings sometimes are severely damaged as they settle, resulting in cracked walls, broken pipes, etc."

* - "Politicians who claim development is not allowed on wetlands either are misinformed or are misleading the public. Steve Doleski, local permit administrator states, "The idea that the Department of Environmental Conservation never grants a permit for use of wetlands is untrue,' adding that all but 5 percent of the cases yield agreements."

* - "The Great Baehre Swamp has already been reduced from 1,200 acres to 584," a loss of almost a square mile of wetland. The still further threatened swamp "stores excess water from one-fourth of Amherst. By trapping and slowly releasing storm water these areas greatly reduce the severity of floods."

* - She called attention to a U.S. Commerce Department report that showed most of Amherst with "a slope of less than one foot per mile," creating a serious flooding problem and to problems "compounded by "experts' who solve localized flooding by running more and more drainage ditches and pipes to the creek."

* - Just days before a February 1985 flood, she wrote: "Arguing over minor details will not make our flood problems go away. When the next major flood hits, hopefully residents will find out the facts firsthand. Then perhaps, they will insist that their board take meaningful action."

* - She condemned the unlimited development supported by a Town Board that overrode even the few permit refusals of the Zoning Board and urged officials to heed fact-finding reports that cautioned against overdevelopment.

And here, the responses:

Amherst Town Supervisor Jack Sharpe led the campaign, referring in one diatribe to "the continuous distortions and misstatements by Peggy Christensen" and adding, "Facts are facts, and all the misstatements that have been appearing in the press lately from Mrs. Christensen and others cannot change them."

In others, he spoke of her "so many misstatements of fact," of her "untruths and incorrect information," adding such encouragements as: "Residents should also understand that because an area is in a flood plain, does not mean their house is going to be flooded."

Amherst Republican Committee Chairman Ralph Cessario referred to her writing as "political claptrap . . . demagoguery and half truths," and university professor Lawrence Southwick chimed in as well.

To her accusers' specific points, she provided detailed factual responses, but the tirade continued.

What has ensued? My wife and I are among those Amherst residents whose homes were flooded in 1985 when the water not only filled our basement but also poured into our first floor. Now we are beset with floor, wall and ceiling cracks due to the unstable soil drying out. Our current problems are, however, far from the worst in the area. Some Amherst residents have structural damage whose repairs will generate expenses in six figures.

Peggy Christensen, truly a modern Cassandra, was right. She remains one of my heroines.

And the Amherst Town Board is creating still another committee.

e-mail: [email protected]

The following letter was written by one of the finest professors at the University of Buffalo-- Dr. Charles Ebert. He taught the "Geography of Disasters" course.

In 1929, and again in 1986, the Soil Conservation Service published detailed soil surveys of Erie County. The 1986 survey contains an extensive reference section, which clearly shows the physical properties and soil behavior of each soil unit.

Moreover, the Town of Clarence Planning Board commissioned a soil interpretation report in 1968. That report outlines eight sections, with text and maps, the properties and recommended use of soil areas. Two sections deal with "soil stability" and with the "suitability of soil areas for residential and industrial planning."

During my 48 years of teaching soils, soil problems and land development, my students had the opportunity to study sensitive soils in Amherst and adjoining townships. We followed with concern suburban expansion, as well as the present manifestations of failing foundations, wall separations, buckling support beams and cracking basement floors.

Several factors contributed to these problems. Much of the area is underlain by a clay type that expands when wet and contracts when drying. In response to artificial drainage and the prevailing drought conditions of recent summers, the clay layers dried out and shrank. This situation weakened the soil's support for structures. Upon temporary wetting, these soils swell and exert pressure on basement walls and floors.

Development is not bad in itself. However, it does result in severe and expensive problems in the absence of careful planning. As a resident of Amherst for nearly 30 years - and certainly not opposed to sound development - I am disappointed that readily available information was ignored.

Amherst, NY

Problems with "Sinking Homes"