Just as trout fishermen search for the perfect stream and tennis players dream of an open court on Saturday, joggers hunt for the ideal path. Washington, thanks largely to the conservation efforts of recently honored retired Supreme Court Justice William O. Douglas, has one - the townpath of the C&O Canal. To fully appreciate it it helps to have endured less noble routes.

When I first started jogging two years ago my efforts were confined to Lincoln Park on Capitol Hill. The Park had several things to recommend it, not the least of which was its location acrross the street from my house. It was also exactly a half-time around, making it easy to measure progress.

But it had its drawbacks. One of its functions was as an exercise area for the local dog population, which was considerable. The caine contribution to the soil was so bountiful that on warm days I was tempted to wear a nose clip.

The second drawback was the heavy traffic, which also made a noxious contribution to the air. I ravenously sucked in during my laps. Metrobuses were the greatest agong; they always seemed to pull out from their stops just in time to envelop me in a black cloud of exhaust. i began to wonder whether the benefit jogging was doing my cardiovascular system would compensate for the damage to my lungs.

A year ago I moved to a quiet area in Northwest and thought I had my prolem licked. I mapped out a two-mile course which began at my doorstep and included one good strenous hill. The new course was fouled neither by dogs nor Metrobuses. But I was now running on concrete sidewalks, which were searing in the summer and jarring to the knees in any season of the year.

One spring day, in an experimenting mood, I decided to try the towpath. What followed was as close to psychologist Abraham Maslow's peak experience as I'm likely to enjoy.The sidewalks of Washington have been spared the pounding of my running shoes ever since.

The noise and odors of the city were replaced by the singing of birds and the sweet smell of honeysuckle. Yellow, white and blue wildflowers lined the path. Instead of the concrete, asphalt of brick of my old routes, I was surrounded by peaceful woods whose dense green foliage reflected in the still water of the Canal.

On weekday mornings I found myself almost completely alone. In the course of four miles I passed one fisherman, a pair of ducks, five turtles and one lizard - who become quite irritated when I went rudely huffing by. The solitude and beauty were as refreshing to my spirit as the jogging was to my body.

On weekdays the Canal takes on a festive atmosphere, with bicyclist, canoeists, strollers and, of course, joggers out in force.

Aside from its scenic tranquility, the towpath has other features which make it ideal. The ground is relatively soft and almost perfectly flat. The trees provide long stretches of welcome shade, and each mile is marked by a wooden post.

I usually start a Lock No. 5 about a mile past Chain Bridge, jog the two miles to Lock 7, then turn around and jog back. I have long felt this to be one of the most beautiful sections of the Canal. It includes some gentle bends which are very pleasing to eyes grown accustomed to the sharp corners and perpendiculars of the city. There are also some outstanding views of the Potomac as it thunders over rapids, above which it lies as broad and smooth as a lake.

Whether you are a hard-core jogger doing a daily five to 10 miles, a more casual one like myself doing a thrice weekly four, or a neophyte yet to complete your first mile, I know of no better place to enjoy this wonderful sport. But be forewarned. Once you try the towpath of the C&O Canal, other routes will pale in comparison.