"The problem with the Patuxent River," said Mike Nelson of the Maryland Department of Natural Resources, "is that it's everybody's backyard."

Look at the map and you see what he means. From Montgomery and Howard counties to the backdoors of Anne Arundel and Prince George's, on down to the forgotten sides of Calvert, Charles and St. Mary's, everybody has a better view out front.

The Patuxent is Maryland's longest river, excluding the Potomac, which is claimed on one side by Virginia. The Patuxent runs 110 miles from a burbling, country trout stream around Damascus and Unity to a wide, brackish tidal estuary replete with crabs, oysters, rockfish and perch in Benedict, Brooms Island and Solomons.

It feeds the freshwater needs of a huge portion of Washington's Maryland suburbs through the Washington Suburban Sanitary Commission's two dammed reservoirs, Triadelphia and Rocky Gorge. And it has long been a dumping ground for whatever Marylanders along its banks didn't want to put in the front yard.

That includes abandoned cars, wash from gravel and sand pits, treated sewage effluent and other junk of a wide variety.

For decades Marylanders ignored the river in their backyard and let the junk pile up. But lately the tide has turned as responsible people began looking closer to home for a recreational and spiritual lift.

The people of the Patuxent have awakened to the fact that the treasures out the back window is turning into a dirt pile. So they did what responsible people do -- they appointed a commission to find out what's wrong with the Patuxent and to recommend ways to fix it up.

This mightily pleases Rich Dolesh, who manages the Maryland-National Capital Parks and Planning Commission's park at Jug Bay in Prince George's, where people come to find out what a marsh is.

Lately it's been getting easier and easier to find out, as the marsh grows bigger and bigger and the river shallower and shallower with sediment from upstream development.

Jug Bay, where seagoing ships tied up 100 years ago, is threatening to become Jug Hill. It's generally only two or three feet deep in the places where it hasn't turned into high ground.

Last week, Dolesh led Constance Lieder, the state planning secretary who also is chairperson of the Patuxent River Commission, and some other interested state officials on a canoe cruise down four miles of the Patuxent near Wayson's Corner, where it divides Anne Arundel and Prince George's counties.

Here's what they saw:

A dump. It used to be a gravel and sand operation, which was bad enough. The operators mined out all the good stuff and left the scarred land to fix itself. Then unscrupulous dumpers dragged in abandoned cars and left them on the banks."The ground is so poor we actually found cactus growing here," said Dolesh. "It's a desert."

When it rains, the desert helps turns the Patuxent a chocolate brown, and grease and oil wash off the abandoned cars.

A pipe. It leads down from a trailer park on the Arundel County side and spills water far clearer than the river water. It looks like mountain spring water, in fact, spilling out of the pipe all crystally clear.

"Yeah. Wait till you get a little closer," said Dolesh. "Take a whiff."

Chlorine, just as heavy and sweet as laundry bleach. Chlorine treats the trailer park's sewage at its own small treatment plant. Chlorine is a biocide, which means it kills bacteria, which means it kills anything living. Which means it kills fish and crawdads and frogs and plankton and worms and whatever else it runs across. This they're pouring in the river.

A crane. The crane sticks out in the river. At the base of it is a big pipe that sucks water out of the river and pumps it up the bank to a working sand and gravel mine. The water washes the sand and gravel, removing the useless silt, which runs out into a settling pond. The settling pond has high banks so the silt will dry and can be dug out and moved to high ground, but somewhere the system has broken down and as you paddle downstream from the crane you see where a small creek feeds into the river.

The creek is chocolate brown, loaded with silt from the settling pond. It forms a plume that is visible for a quarter-mile downstream, spreading as it goes until it almost spans the river.

At a creek. It's called Western Branch, which is the same name as the Washington Suburban Sanitary Commission's sewage treatment plant up the creek and out of view. The plant, Dolesh says, has a permit to introduce up to 10 million gallons a day of chlorine-treated sewage effluent. Repeat: 10 million gallons a day.

These are some problems the state officials saw and with which they and the Patuxent River commissioners intend to deal. Fred Merkle, who lives on the river and is the Prince George's commission representative, hopes they do. He remembers back in 1968 when other recommendations were approved by the state, including one to check twice yearly every spot where anything drained into the river and to prosecute anyone illegally dumping. But, he said, "There wasn't a single prosecution that came out of that."

Dolesh kept saying how hard it was to talk about the problems of the Patuxent while enjoying a pleasant day canoeing on it, since it remains largely a quiet, scenic escape from the clatter of the suburbs.

But his wife's family comes from Benedict, where the effects of what goes on upstream are expressed in declining catches of those who live off the water, and he spends his working days at Jug Bay, which keeps getting bigger.

So he knows something is wrong.