IF WE WERE unschooled, but attuned to nature, instead of the other way around, we wouldn't need to study and dissect all the ways water dies as you develop its watershed.
We would just accept that when you keep wounding any animal - in this case the watershed, the creature containing all other creatures - as you replace its living, breathing skin with dead concrete and asphalt, you are killing it.
Eventually, modern ecological science does tend to bring us to the same place as native wisdom.
So it was that last week a few fisheries scientists from Maryland's Department of Natural Resources traveled to Southern Maryland to suggest something bold.
Mattawoman Creek, one of the bay's healthiest, fishiest and flat-out loveliest tributaries, which flows between Prince George's and Charles counties, is approaching a threshold, a level of development beyond which its fabled quality could start an irreversible slide.
The key, DNR biologist Jim Uphoff told a citizens' water quality committee, is "impervious surface," the sum total of roads, driveways, sidewalks, rooftops, compacted soils and parking lots in the area.
When impervious surface in a stream or tidal creek's watershed reaches about 10 percent, Uphoff said, water quality and other fish habitat get pushed over an edge.
Ten percent might not sound like much, but consider, even Baltimore City is at only 35 percent, and heavily suburban parts of Anne Arundel County's coastline are at 16 percent to 18 percent.
The Mattawoman Creek area is at about 8 percent or 9 percent. But growth planned in its watershed could raise that to 20 percent impervious surface in the next couple decades, the DNR biologists said.
Such a rise in developed land correlates strongly with declines in aquatic oxygen and an increase in toxic PCBs in fish; also with destabilized freshwater flows, as rainfall has fewer places to soak in to recharge streams with groundwater in droughts.
The 10 percent threshold, in freshwater streams and around tidal creeks and edges, appears to be universal, documented from the Baltic Sea to the Hudson River, and from the Pacific Northwest to the Chesapeake.
"We've never done this kind of presentation before," Uphoff told the Lower Potomac Tributary Team. "But as impervious surface around the state goes up, it becomes harder and harder for us to manage fish.
"We looked at the development projected down here and thought, `We've got to try to get ahead of the curve instead of just reacting,'" he said.
