* WATERMARKS: Some river-goers believe living in Washington and not paddling is sort of like living in Aspen, Colo., and not skiing. It is hard to disagree, as the whitewater (and flatwater) around here long has been a huge draw. The Potomac, from Great Falls to Little Falls, is a close-in highlight, but there are many great runs (the Cheat Canyon, the Lower and Upper Youghiogheny, etc.) reached by moderate drives. To that end, the Potomac Conservancy and Potomac Paddlesports have paired up for a series of "Discover the Potomac" paddle trips; the next one is Saturday at 8:45 a.m. at Pennyfield Lock off River Road in Potomac. The four-hour journey will be led by trained instructors and beginners are welcome. For more information, visit www.potomac.org and www.potomacpaddlesports.com. . . .

The Potomac Conservancy is looking for volunteers for a river cleanup project at Fletcher's Boathouse in Washington on Saturday at 9 a.m. Work gloves and trash bags will be provided. To sign up, contact Laura Glass at LGlass@MICROS.COM. Also, the Potomac Conservancy, with REI and the Fairfax County Park Authority, will conduct a trail restoration project at Riverbend Park in Great Falls on Saturday. Event starts at 8:30 a.m. Visit www.rei.com for more.

* SHIFTING GEARS: The Mid-Atlantic Off Road Enthusiasts will go to Schaeffer Farm in Germantown on Tuesday for its Early Bird ride. Pace is casual on intermediate terrain. Meet in the parking lot at 5:45 a.m. Trek will be led by Jason Ashmore (240-593-4879). If you're not a morning person, then go to Wakefield Park in Annandale on Tuesday at 6:30 p.m. for a casual ride on easy terrain. Trip leader is Peter Beers (571-241-6666). For more about MORE, visit www.more-mtb.org/. . . . The third race in the Wednesdays at Wakefield Mountain Bike Race Series is this week. Registration starts at 5 p.m.; racing begins at 6 p.m. Visit www.potomacvelo.com for details.

* ON THE GOOD FOOT: The Mountaineering Section of the Potomac Appalachian Trail Club will hold its monthly meeting on July 14 at PATC headquarters, 118 Park St. SE, Vienna, starting at 7:30 p.m. . . . The Blue Ridge Section of the American Alpine Club will hold its monthly meeting on July 19 at 7:30 p.m. at the Rhodeside Grill, 1836 Wilson Blvd., Arlington. Non-members welcome. For more information, contact Simon Carr at aac_brs@hotmail.com.

-- John Mullen

mullenj@washpost.com