Down by the riverside, the muddy water rippled in the sun. Mint-green leaves on sprawling shade trees fluttered in the wind.

Along the tree-lined east bank of the Anacostia River, beneath nature's leafy umbrellas, respite could be found from the raw heat of summer, the steam and sizzle of a 100-degree Tuesday.

At Anacostia Park in Southeast Washington, there was the slumberous movement of fishermen, the gentle strokes of a painter alongside an urban stream, the nearly silent hand-in-hand motion of a couple roller-skating in the pavilion.

Danny Kelly, 39, plucked another slithering night crawler from a cold cake of mud. The thinly muscular man wearing shorts and a cap to keep the sun out of his face baited two silver hooks on his black fishing pole, then flung his hook over his right shoulder. Plop. It landed in the middle of the river, away from the trail of floating paper cups, candy wrappers, potato chip bags, Popsicle sticks.

Plop-plop . . . .

"Look at them big fishes jumping out there, man," Kelly said, laughing. "You can see 'em jumpin', but they ain't jumpin' on this hook."

He had been fishing since high noon. And after about an hour, he had netted only a few fat twigs and a not-fat-enough catfish, which he hurled back into the water. Splash.

Now, Kelly was sitting atop his green-and-white cooler, sipping from a bottle of ice water, waiting for a convincing nibble. A gentle breeze helped pass the time.

Under a nearby tree, David Thomas--bearded and jolly--painted in the shade, a gray hubcap his canvas. He spread cherry-red gloss enamel with a gentle, left-hand stroke.

It is Thomas's hobby--beautifying the cars he buys from junkyards, like this spruced-up, cherry-red '86 Colt parked at the curb, for which he was painting the hubcaps to match.

"First when I started doing cars, people thought I was crazy," said Thomas, 39. He chuckled. "Like I say, it doesn't take much to be happy. You just have to be happy with what you have."

Up the road, under the shade of the pavilion, a radio station blared over speakers.

"It's too hot to do anything," a deejay's voice echoed across the pavilion.

After a morning of outdoor tennis, Micki Minor, 41, and Ben Mills, 42, decided to go skating in Anacostia Park, enjoying the manufactured shade of the pavilion.

"You can't go wrong under here," Mills said, the couple's cool jug of water not far away.

The music started. Then the motion.

They skated to a love song, sweating from the heat, but flowing like waves on a river--and a summer breeze.

CAPTION: Ben Mills and Micki Minor were the only roller skaters at the pavilion in Anacostia Park yesterday. People throughout the park sought solace in the shade.