Land Subsidence in the Town of Clarence

It turns out that underlying mines are not the only thing that can cause land subsidence in the Town of Clarence. From an article in the Buffalo News, we learn that the installing of sewer pipes, if not done in a forward-looking manner, can cause soil problems also . The photo is of Gary Wright of Old Goodrich Road, and his drained pond(from the News).

Basically, the land around Clarence and Amherst is largely compacted clay. When a sewer line is put in, the land is dug up, pipe laid, and the area is filled back in. Therein lies the problem. The fill is no where near as compacted as it started out, and water is sucked in to fill the gaps. A simple example of this comes from, of all places, an article on time management called "Cup of Coffee with a Friend", which illustrates that even when you think the container is full (of golf balls, then pebbles, then sand) there is always room for more (coffee).

The real life corollary is that when the trench is filled with dirt and gravel, it has room for water, which comes from nearby clay and groundwater. This dries out the land causing shrinking, which in turn cracks basements, creates sinkholes, and drains ponds.

One would like to think that those in the construction industry would act responsibly on their own, after all, it's their reputations. The truth of the matter is, for the most part, that they do the bare minimum of what is required by existing law. When they don't, they get fined and forced to do it right. The towns don't seem to ask for more either, as that might hold up construction or add to the expense.

Ideally, everyone would want to do the right thing all the time, no matter what the cost. There is a method involving "check dams" that helps to prevent this scenario. The Town of Amherst requires them on water lines, but not sewer (?). Erie County uses them on their own sewer lines in the Southtowns. They are commonly required throughout the country to protect wetlands, or to keep dry areas from becoming even drier.

In reality, it's whatever is the most convenient, until laws are changed to benefit the homeowner and enforce accountability by contractors and the areas effected. Incidentally, the Town of Clarence rejects claims that the problems are related to the sewer construction. The engineer from the Town of Amherst finds it to be an "interesting theory."

Mines, Sinkholes, and Other Fun Stuff

I heard that they want to build houses over the old gypsum mines on Roll Road. What a wonderful idea (roll eyes). I can remember, as a child, hearing the booms as they dynamited in the mines. That's what led to this:

I was roaming around the internet, reading some of my usual blogs when I wandered over to DeputyDog (I click on the links a lot). He has some wonderful photos of "7 Amazing Holes" - large mines, "glory holes", and sink holes.

One thing led to another, and I came upon stories of mine pillars collapsing and causing sinkholes, which pull buildings and roads down into the ground due to land subsidence .

"Land subsidence also occurs in areas of underground mining where removal of material causes overlying surface rock to sink or collapse. Although the locations of underground mines are often denoted on topographic and geologic maps, the potential subsidence hazard from a mine requires evaluation by a geologist."

"Similar to land subsidence due to underground mining, subsidence can also result from chemical weathering of soluble rocks (e.g. limestone, dolomite, gypsum). As groundwater flows through limestone, a chemical reaction causes the rock to dissolve, eventually forming cavities within the bedrock. As a cavity near the surface increases in size, the overlying materials can sink or collapse and create a depression on the land surface."

Tar Creek, OK is one town that has been subjected to sinkholes and threats of mine collapse for years. There are also the real toxic threats from the dust to the air and acid mine water that contaminates the water table. While it was zinc and lead mined there, gypsum , used primarily in wallboard, has its concerns also:

"In the early 1980s, landfills in British Columbia were found to be producing toxic gas and leachate from concentrations of gypsum debris that had been buried for as little as two days."

One would think that the Town of Clarence would want to shield itself from future lawsuits. There can be all kinds of studies, but that doesn't mean that the earth won't do it's unpredictable thing and shift. Then again, Amherst is off the hook for it's sinking homes.

The prevailing thought just might be that if they're insurable, and the Town's not liable, go for it. Add to the tax base and services needed, subtract from green space. Just think twice before buying a house there.