After more than two years of debate, officials from the Bay region have concluded that they will consider all sprawl as “harmful,” although it will be next summer before they know how much of it is taking place in the watershed.

The Chesapeake 2000 agreement called for a 30 percent reduction in the rate of “harmful sprawl,” which is blamed for degrading streams and intensified Bay pollution because of the increased runoff from streets and parking lots, and air pollution from people driving ever-greater distances.

But interpreting the goal had been bogged down as officials from state and federal agencies could not agree on what constituted harmful — as opposed to non-harmful — sprawl.

Instead, officials have now agreed that sprawl will be measured as the conversion of agricultural and forest land to urban land, rather than as any particular type of development.

Ironically, that was the definition used in an early draft of the Chesapeake 2000 agreement but rejected at the insistence of then Virginia Gov. Jim Gilmore. The “harmful sprawl” language was used instead.

In an effort to define harmful sprawl, a group working on the issue developed “principles of good development” which called for such things as developments that did not fragment forest and farmland or harm water quality.

In the end, though, officials concluded that although they might be able to define harmful sprawl, it would be impossible to track the impacts of individual developments throughout the watershed.
“It turned out that it wasn’t practical to try to measure that,” said Martha Little, of the Virginia Chesapeake Bay Local Assistance Department, and chair of the Land, Growth and Stewardship Subcommittee.

“It’s easier for the counties and other jurisdictions to understand,” agreed Deborah Weller, of the Maryland Department of Planning, and a member of the subcommittee. “We have been pushing all along to go with a land conversion measure.”

But, Little noted, the Bay states will still promote the “principles of good development” to developers and local governments so construction that continues to take place will cause less harm to the watershed.

“We still think there can be development that has less of an impact on water quality. and that is the thing we will be focusing on, anyway,” she said.

No one will know until next year what the sprawl goal means in terms of acreage.

The Chesapeake 2000 agreement called for reducing the rate of harmful sprawl 30 percent by 2012 from a baseline rate of development that would be measured between 1992 and 1997. Those dates were selected because they coincide with the five-year release dates for the U.S. Department of Agriculture’s Natural Resources Inventory.

The NRI uses a statistical sampling technique in which randomly selected areas on the ground are surveyed for their respective amounts of urban, rural and other land uses. That land use pattern is extrapolated over a broader area.

NRI data showed that between 1992 and 1997, about 128,000 acres a year in the Bay watershed were converted from the NRI’s forest or agricultural land use classifications to one of its developed classifications. That would have meant the 30 percent goal would limit development to 90,000 acres a year, an area roughly twice the size of the District of Columbia.

But some objected to the use of NRI data. Maryland officials, for instance, contended its statistical sampling techniques poorly represented their state: NRI data showed a rate of development nearly three times greater than Maryland Department of Planning figures.

The Chesapeake Bay Foundation also said the NRI was ill-suited for measuring sprawl. The CBF’s own analysis in 1996, made from various state and federal records, suggested about 90,000 acres was being developed annually in the mid-1990s. A 30 percent reduction from that figure would limit development to 63,000 acres a year.

As a result, the Bay Program has determined that sprawl will be measured using Landsat satellite images analyzed by the Mid-Atlantic Regional Earth Science Applications Center at the University of Maryland.

Officials acknowledge that solution is not perfect, either. RESAC can’t detect low-density development much beyond about one dwelling over five to eight acres, so some land conversion caused by large-lot subdivisions — and the beginning of encroachment upon rural areas — will likely go unseen.

“That’s still sprawl, but the analysis is better than that using any other other data,” said Lee Epstein, lands program director with the Chesapeake Bay Foundation and a member of the subcommittee. “RESAC is the best thing around; I don’t think we have a choice.”

What no one knows right now is how RESAC data will actually compare with the NRI in terms of measures of development. The Bay Program expects to get information about 2000 land use this fall, but will not get 1990 land use until next spring. It’s anticipated that the rate of change between those two years will become the baseline from which the 30 percent goal will be measured — a number expected next June.

Also unclear is the “end date” for measuring the 30 percent goal. The original wording called for 2012 because it coincided with the five-year release cycle for the NRI. But the Bay Program, which plans to use RESAC land use figures every 10 years in its computer models that estimate nutrient runoff, would have to spend an extra half-million dollars or more to purchase 2012 data.

As result, officials believe the goal will likely need to be measured in 2010, or 2020, but no date has been selected.