We’ve all been warned that you can use statistics to prove just about anything. But the latest report on land use trends in the United States provides plenty of evidence that the Chesapeake Bay Program partners were right to single out the loss of farms, forests and other open space to development as a defining issue in the Chesapeake 2000 Agreement.

Last December, with great fanfare, the vice president and the secretary of Agricul ture announced the results of the latest National Resource Inventory, a part of the 1997 Agricultural Census. The census is completed every five years, and the new NRI includes data and trends from 1982, 1987, 1992 and 1997. It is based on an extensive sample of non-federal land nationwide, and is a credible source of regularly reported land trends data.

In particular, the NRI provides a reasonably accurate picture of the conversion of open land to developed land, an issue that has received a great deal of attention in current debates over the land use provisions in the Chesapeake 2000 Agreement, due to be signed in June.

The December report presented data on a state-by-state basis, and provided some tantalizing glimpses of what might be happening in the Chesapeake watershed. The statewide numbers for Bay watershed showed an increase in developed land area from 1982 to 1997 as follows:

Statewide Increase in Developed Land Area 1982-1997

Delaware ...........42%

Maryland ..........40%

New York ..........27%

Pennsylvania ......56%

Virginia ..............49%

West Virginia .....65%

Once everyone got over the sheer size of these numbers, there were some subtler surprises. For example, the state with the most active effort to stop sprawl in recent years, Maryland, had one of the lowest rates of conversion (we will see part of the explanation below). And, the rate in Pennsylvania seemed unusually high.

The speculation began. Much of the change in Pennsylvania, it was suggested, was in the Pittsburgh and Philadelphia areas, both outside the Chesapeake watershed. On the other hand, it was thought that Virginia’s low numbers were due to the influence of the undeveloped, primarily rural half of the state outside the watershed. So the Chesapeake watershed numbers, when we got them, would show a drop in the rate of loss of open space in Pennsylvania’s portion, and a rise in Virginia’s. Maryland, which is nearly all in the watershed, would stay essentially the same. And the largely rural areas of Delaware, New York and West Virginia in the watershed would show smaller losses than the urban areas elsewhere in those states. So we thought.

We asked the Department of Agriculture to do the numbers for the Chesapeake watershed, and the results are just in. They provide a lot of food for thought:

Increase in Developed Land Area 1982-1997 ...State....Entire State Watershed Portion

42% .............................................................Delaware .....................................61%

40% .............................................................Maryland ....................................40%

27% .............................................................New York ...................................34%

56% .............................................................Pennsylvania.............................. 66%

49% .............................................................Virginia ......................................56%

65% .............................................................West Virginia ...........................141%

The conventional wisdom was right about Maryland — it didn’t change. But every other state showed a higher rate of loss of open space in its Chesapeake watershed portion than statewide. However, Virginia’s rate in the watershed did not go up as much as expected; in fact, it rose less than Penn sylvania’s remarkable increase! West Vir ginia’s rate of loss in the upper Potomac basin is downright alarming, even accounting for the exclusion of National Forest lands from the survey. And the primarily rural parts of New York and Delaware in the basin are losing open land faster than the rest of the state.

The first thing to conclude from all this is that we are under a lot of development pressure throughout the watershed. Because the NRI is sensitized to pick up large-lot subdivisions within farm and forests areas, what we are seeing here is a high level of what might be called “rural sprawl.” The prevailing pattern in these areas is less standard grid subdivisions, and more individual houses spreading out along country roads and highways. Acre for acre, the impacts are not a lot different, and the provision of services may in fact be more costly to locals.

The second question is, what is going on in central Pennsylvania? It seems that Gov. Tom Ridge’s “Growing Greener” proposals and efforts to reform local government roles in land use planning and regulation may be happening just in time to save the commonwealth’s farms and forests from an onslaught of development.

Finally, what accounts for the slower conversion rate in Maryland? Part of the answer lies in the fact that Maryland started from a higher base of developed land, so that the percentage increases for the same acreage of development are comparatively less. The figures for the Chesapeake basin by state for developed land as a percent of the total are as follows:

Chesapeake Bay Watershed Percent of Total Developed Land By State, 1982 & 1997

1982...........................State................................ 1997

5% ............................Delaware .............................8.5%

12% ..........................Maryland ...........................17%

5% ............................New York .............................7%

6.5% .........................Pennsylvania ......................11%

8% ............................Virginia ..............................12%

3.5% .........................West Virginia .......................8%

It is clear that Maryland did start from a higher base in 1982. But it is alarming how the other states are catching up. Virginia now has as much of its total land area developed as Maryland did a mere 15 years ago. And Pennsylvania is only a little behind Virginia and catching up. All three states now have more than 10 percent of their land in the Chesapeake watershed in development. Interestingly, that is about the level of development on a smaller scale that most of the experts claim begins to permanently alter the ability of creeks and streams to perform their natural functions. The picture is somewhat rosier for our friends in Delaware, New York and West Virginia, where developed land remains less than 10 percent. But the trends to more conversion are clear in all three states.

Clearly, the Bay partners are on to something important here. And the time to agree on goals for sound land use is upon us now, as we debate the final provisions of the new agreement. We can only imagine what the Department of Agriculture will be telling us 10 years from now if we fail to act decisively.