To look around downstream, you'd think the predominant species was the Budweiser can and its natural habitat was stream banks about to collapse.
Upstream, this unnamed tributary to the Little Patuxent River in western Anne Arundel County is a tribute to man's engineering skill in keeping water away from traffic.
It has the markings of a stream in an urbanized area.
Last week, a team of five Department of Natural Resources biologists armed with nets and meters stopped at four places to check its life -- or what's left of it. The information they're gathering is part of the $600,000 Maryland Biological Stream Survey, the most comprehensive assessment of stream health ever done in the state.
Over three years, researchers will look at all 19 basins in the state. Each spring, they'll sample water quality and take an inventory of aquatic bugs, and each summer survey fish and make a habitat assessment, said Ron Klauda, director of the Chesapeake Bay Research and Monitoring Division.
Information will help determine such things as which streams should be protected or restored and how, which ones can be stocked with various kinds of sport fish, what diversity is being lost, the effect of Maryland's high rate of acid rain and what kind of development curbs will help most.
"It has to do with land use. It gets down to the counties," Mr. Klauda said. "Initially, it is at the county level where most of the control can take place."
Maryland has nearly 15,000 miles of streams, many of them small creeks that feed into the Chesapeake Bay.
"Ultimately, you need good stream systems to contribute to the health of the bay," Mr. Klauda said.
"By looking at the habitat -- meander, straight, the bottom, the bank -- we can make some inferences about what is going on in those streams," he said.
In doing so, Maryland joins a growing number of states taking this type of pulse of their waterways as an ecological barometer. Of its immediate neighbors, only Delaware has done such a comprehensive survey, Mr. Klauda said.
"I applaud the state of Maryland for taking a biological stream survey. They need to know what resources are there so they can protect them, have a baseline and assess what damage has already been done," said Randy Showstack, a spokesman for American Rivers, a conservation lobby group.
Few species found
"If you only see four to five fish species in a coastal plain stream, either you have a very small stream or you have a problem," said Paul Kazyak, survey coordinator.
What researchers found in the tributary on Wednesday were few species of fish -- many of them diseased -- and plenty of evidence that the stream is severely stressed, even at the bend in the Little Patuxent River in western Anne Arundel County. This is its most natural setting, a few hundred feet from a road, and even this semiwooded habitat in the Patuxent River Basin ranked poorly on the scale.
"It's definitely not the diversity we'd expect to find, sadly, this close to the Little Patuxent River," said Scott Stranko, crew leader. "And it just completely diverged from its natural course."
Researchers wearing waders netted off a 75-yard segment of the stream for study. Electroshocking -- stunning fish with a small current in the water -- turned up only seven kinds of fish. Here, as in the other three survey sites, most of those were types tolerant of poor habitats, such as eels and fall fish, and many suffered black spot or red spot parasitic ailments. Tallied, they weighed a scant 416 grams.
Where the stream enters the river, rocks and gravel from upstream create a bar. To dislodge those fist-sized rocks, the water, though usually barely moving, has to course with a velocity of several feet per second during storms.
Atop eroded banks, tree roots spike in the air, several feet of dirt below them flushed away by high flows of speeding water. It's only a matter of time before those trees will fall into the stream and the bends they held are gone, the biologists said. About 100 feet upstream in an area where the stream once obviously meandered, biologist Mike Naylor stood in less than ankle-deep water, though the stream bank was above his head.
"You don't see many like this, that are this dramatic," said Mr. Naylor.
"It's indicative of a major perturbation upstream," Mr. Stranko said.
And there are several.
Stream starts at fort
The mile-and-a-half-long stream starts at Fort Meade, where 640 acres that include everything from forest runoff to military housing drain into it. It winds into a detention pond, where some dirt and pollutants settle, then runs unnaturally straight amid parking lots of the National Security Agency, where it takes on a greenish hue -- denoting algae -- and holds a telecommunications cable.
It then flows in a cement and rock channel and collects parking-lot runoff from underground pipes fed by storm drains, each culvert adding more pollutants.
"Concrete is a very, very poor habitat for anything. You don't see much life in concrete," Mr. Stranko said.
"The purpose of all this is to get the water off-site and downstream," said an environmental scientist for the Department of Defense. "The concept of designing with nature wasn't here 40 or 50 years ago."
Officials hope to create a half-acre wetland in the middle of this, and would create more if the soils were more cooperative, said the scientist.
Just below the concrete splash-ways the crew found lots of fish -- but mostly blacknosed dace that can live just about anywhere, even in this water that's 89 degrees.
The stream then meanders slightly through woods until it reaches Route 32. Huge pipes whisk the water under the highway, where a man-placed cascade of rocks creates an elbow-turn, sending the water into more pipes under the Route 198 ramp. The stream runs nearly straight, and here, where theoretically there should be well over a dozen species of fish, researchers found five.
The stream takes a few bends, including one where a grain farmer placed boulders on the bank to halt erosion. From there, it runs through the woods and into the river. Throughout, much of the naturally graveled stream bed is suffocated with the fine silt eroded from banks and the flood plain. A natural bottom would offer fish and bugs predator protection and places to lay eggs, but the silt does neither.
Worse streams seen
Depressing as researchers found the tributary, they have seen worse. A tributary to Oxon Run in Prince George's County that ran mostly in a concrete trench had a solitary dweller: one blacknosed dace living in a cast-off tire, Mr. Stranko said.
On the other hand, Mr. Stranko said, the stream "still has life in it, so it is not completely gone." While it is probably too late to help the upper half of it, "there may be ways to damper some of the impacts downstream."
This is also the year for assessments of the West Chesapeake Basin, which includes surveys in Saltworks, Flat and Plum creeks and Severn Run in Anne Arundel County.
Other river basins being sampled this year are the Youghiogheny, Lower Susquehanna, Choptank, Pocomoke and the Washington-area of the Potomac.