Monday, July 21, 2008

Sinkholes proliferating in fast-growing Va. county

Officials in Loudoun County, Va., are calling for new regulations to protect residents living in areas prone to sinkholes and to avoid contamination of local water supplies, writes Sandhya Somashekhar for The Washington Post. Dozens of sinkholes, many of which are less than a foot wide, have opened up between Leesburg to Point of Rocks near the Maryland border, a 28.5-square-mile area, since 2000. A chasm was created in the middle of Route 15 in 2005, and at least two 30-foot-wide and 30-foot-deep sinkholes opened near a proposed housing development.

County officials blame the problem on the rapid development of land resting on soft, porous limestone, also known as karst. Groundwater pollution occurs when pesticides and other contaminants reach the water supply and is another hazard of building in such areas. The county adopted regulations in 2003 that limited development in limestone areas, but the plan was thrown out by the Virginia Supreme Court because of a technicality. Growth was supported and limits on development in limestone areas were rejected by supervisors who took over the board that year, but some regulations governing construction in limestone areas were supported in the waning weeks of the pro-growth supervisors term last year. The current board supports slower growth rates and is scheduled to consider new regulations for limestone areas in Loudoun, one of the nation's fastest-growing counties.

"It is one of our most sensitive geographic areas," says County Supervisor Sarah R. Kurtz, whose district includes most of the limestone area. "We have historically seen an increase in sinkholes as development has gone on in the corridor. It's a matter of preventing property loss--as in your whole ... house goes down a sinkhole." Sinkholes have opened up across the region because of heavy rains in recent months. The county ranges from very rural in the west to heavily suburbanized in the east. Read more here.

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