The Potomac River above Washington is gaining an unfair reputation as a sinister death trap full of sneaky currents and lethal holes.

It's not necessarily so. On Sunday, for example, Ashley McEwan of Germantown ran the eight-mile stretch from a mile below Great Falls to a mile above Little Falls Dam in a kayak, finishing second in class in the Canoe Cruisers Association's annual whitewater race.

McEwan negotiated turbulent Wet Bottom Chute; the Maryland chute at Difficult Run; Yellow Falls, where the river cascades over jagged rocks; Stubblefield Falls, full of big, standing waves, and finished to a round of applause from folks basking in the sun on the banks at Sycamore Island.

She is 9 years old.

"She was a little nervous," said her father, Tom, who accompanied her in his own boat. "She's never been in water this big before. The boils and currents were a little confusing."

The McEwans were in two of 48 boats competing in the 31st running of CCA's race. No one ever has been injured in these races, though Sunday's was a far cry from the initial 1956 edition.

"The first race was considered so dangerous, only invited experts were allowed to participate," said John Seabury Thomson, one of the organizers. "Now we've reached the point where it's the race of choice for beginners, as long as they have some sense of the river."

What happened between 1956 and 1986 to make the Potomac safe even for 9-year-olds? Area canoeists and kayakers became familiar enough with the river's dangers that today, anyone who cares to ask can find out all he needs to know about the perils of boating here, and how to avoid them. With a planned route and safety boats at all rapids, the CCA race may be the safest whitewater boat ride in the United States.

So why is it that 56 people have drowned in the same general stretch of river over the last decade, according to a recent study for the National Park Service?

"There's a pattern to drownings in the Potomac," said Dick Stanton, superintendent of the C&O Canal Park, whose territory abuts the river from Edwards Ferry to Georgetown. "Usually, the ones who get in trouble don't know what they're doing.

"They buy a $29 raft, put in somewhere they don't know and go straight into a dangerous place.

"I've paddled this river all my life," said Stanton, "and never had a problem. But you take people from out of town, people who don't know what they're doing . . . "

Two people have drowned on the river already this spring. One was a teen-ager who, with a friend, unloaded a raft at Great Falls, Va., walked upstream and put in a mile above the most dangerous rapids in the mid-Atlantic region. As they plummeted toward Great Falls without life jackets on, his friend grabbed a tree and hung on. The victim went over the falls.

The second was a fisherman, unable to swim, who rented a 12-foot johnboat at White's Ferry, declined the life jacket offered him, and drowned when the boat capsized.

These people knew less about the river than a 9-year-old who listens. They were ignorant of the dangers and paid for it with their lives.

So why are so many people ignorant of the dangers of the river? The answer isn't simple.

"What you have here is a fundamental lack of centralized authority," said Thomson. Technically, the river belongs to Maryland, though it runs through the District and Virginia and alongside great stretches of federal parkland on the Maryland side.

For years, government policy toward the Potomac in the face of this mishmash was to ignore it and discourage its use by warning of pollution and dangers. But in the last 20 years, with the river cleanup, more and more people are using it.

The National Park Service has made educational strides, posting informational plaques and warnings at popular put-ins and access points, but the only officers regularly patrolling the river are eight NPS rescue workers, who must cover about 50 river miles, 24 hours a day, Stanton said.

Since no agency can adequately patrol the river, education is the key to reducing mortality on the Potomac, Stanton said.

One wonders why the various governments -- Montgomery and Fairfax counties, Maryland, Virginia and the District -- and the Park Service can't put together a Potomac River Recreation Commission, the same way the various factions have organized to oversee commercial fishing on the river below Washington.

Give an outfit like that some money from its member jurisdictions and some authority and it might begin to unravel problems and spread the word. For starters, it might hire a dozen or so of the top area college-age kayakers and canoeists to paddle the river regularly as summer employes, dispensing information, helping people on the verge of getting in trouble and passing advice on what's safe and what isn't.

The Potomac, in the view of many, is just as compelling a recreational resource to this area as the ocean is to Coney Island and the lake is to Chicago. The difference is, New York and Chicago accept the responsibility to protect people from the obvious dangers of a compelling resource. They hire lifeguards.

The Washington area, with its hatful of governments tripping over each other's feet, doesn't, and winds up wringing its hands.

The best simple rules to follow for boating safety on the Potomac are these: Stay away from Great Falls, Little Falls Dam (two miles above Chain Bridge) and Little Falls (one mile above Chain Bridge). Always wear a life jacket; never paddle alone; know your skill level and stay within it; avoid cold weather; don't paddle any river in flood.

The CCA for years has held excellent, inexpensive canoe and kayak classes for beginners through experts in June, July and August. For information, write John Thompson, 2221 Scotch Ct., Woodbridge, Va. 22191.