RIVER RIDE: The Canoe Cruisers Association and National Park Service are planning a day on the Potomac Thursday. Canoeists and kayakers are encouraged to come to the tavern at Great Falls Park on the Maryland side at 10 a.m. to meet new NPS superintendents Tomm Hobbs and Kitty Roberts, then paddle a stretch of river. For information, call John S. Thomson at 656-3630.

UP THE WALL: Competitive rock climbers from around the nation compete on a 60-foot wall at the Springstone 90 sport-climbing competition in College Park next weekend. The wall's strategically placed handholds and footholds were designed by Recreational Equipment Inc., on whose parking lot at 9801 Rhode Island Ave. the competition will start at 9 a.m. Saturday and noon Sunday. There's a $2 charge for spectators Sunday. Call REI at 1-800-426-4840.

PEDAL PUSHERS: Seventy-five bike riders from 12 nations and five continents launch a cross-country bike tour for Youth Ending Hunger from Lafayette Park at noon Tuesday. They aim to draw attention to the thousands of children who die daily from hunger.

ROAR NO MORE: Maryland's Department of Natural Resources is cracking down on noisy muscle-boat drivers with a change in maximum allowable decibel levels on pleasure boats. The old limit was 82 decibels; the new one is 75 decibels, measured from shore and effective immediately. Anyone running a pleasure boat that makes more racket than that is liable for a $500 fine.

FISH TALK: This is National Fishing Week, so some merchants got together and ran a nationwide fishing tournament for kids. They're bringing 20 winners from 10 states to Washington on Monday for a four-hour bass contest on the Potomac. Weigh-in is at noon at Washington Harbor in Georgetown.