C. Bernard "Bernie" Fowler took his annual stroll into the Patuxent River on Sunday, leading a ragtag band of about 100 river lovers who waded with him to measure its clarity.

In a ritual he has observed for the past 12 years, Fowler, a 75-year-old former state senator, walked fully clothed into the water until he could no longer see the white canvas sneakers that covered his feet.

The so-called "Bernie's Sneaker Index" was measured at 41.5 inches. That is, Fowler could no longer see the toes of his sneakers when the water reached 41.5 inches -- about hip level. This year's index was about six inches higher than last year's reading of 35.5 inches. Fowler's goal is to restore sneaker visibility to chest depth, about 63 inches.

He said strong winds the night before the wade-in may have stirred up the river, increasing cloudiness. "There was a 20-knot gale coming from the east the night before," said Fowler, who entered the river from Broomes Island in Calvert County. "That could make it less transparent."

He said he noticed something different this year. "I didn't see as much submerged aquatic vegetation," Fowler said. "That's what they call it now. All my life we called it seaweed. But last year it was abundant. I was looking for the same thing and didn't see as much."

Fowler, who retired from the state Senate in 1994, is an untiring advocate of the river. In 1976, he led a successful lawsuit against the state that forced Maryland to stem river pollution by installing sewage treatment plants and pump-out stations along the Patuxent.

Fowler, who grew up on Broomes Island, has boyhood memories of wading into the river up to his chest and spotting crabs on the bottom. As development exploded around the Washington-Baltimore region, the river grew cloudier and soft-shell clams, blue crabs and croaker grew scarce.

Gradually, since 1976, the health of the river has been improving, environmentalists say.

The Patuxent River, 110 miles long, is the only major Chesapeake Bay tributary lying completely within the state's borders. It runs through Montgomery, Howard, Anne Arundel and Prince George's counties before it broadens in Charles, St. Mary's and Calvert counties and empties into the bay.

Fowler says his annual wade-ins are a chance to focus public attention on the health of the river. In recent years, the state Department of Natural Resources and environmentalists have encouraged similar wade-ins along the bay. Fowler says imitators are the sincerest flatterers -- and help the cause.

"We've got the whole bay to clean up, so the more we have these wade-ins and fish-ins, the better," Fowler said.

CAPTION: Former state senator Bernie Fowler, in overalls, wades into the Patuxent with his grandson, Cody Fowler, to test the river's clarity. Flanking him are state Sen. Roy P. Dyson and Mona Monsma, who is holding Fowler's great-grandson, Alex Osburn.

CAPTION: A chart lists the results of Fowler's annual "Sneaker Index," showing greater river clarity in the 1950s and '60s, with gradual recovery since the late 1980s.

CAPTION: Advocates of better water quality wade into the Patuxent River in support of former senator Bernie Fowler's annual "Sneaker Index" -- a test in which Fowler checks the river's clarity by walking in until he no longer can see his feet.