Discover some inner-city serenity in Allied Gardens Navajo Canyon.

Throughout the San Diego area, thin strips of canyon open-space break the symmetry of the urban/suburban continuum. Sometimes these shreds of natural landscape survive by design. In other cases -- in older neighborhoods especially -- the canyons survive because they were too steep and narrow to ever have been developed in a practical way.

Some 37 canyon bottoms within San Diego's city limits, ranging in length from 0.2 mile to 6 miles, are scheduled to receive "improvements" in the form of new or expanded utility maintenance roads. A number of local citizen groups are opposed to this plan or at least concerned that it will mean further environmental degradation of plant and wildlife habitat. I (and about 80 other people) recently joined an informational walk down the obscure Navajo Canyon sponsored by the Sierra Club to learn more about the issue. Navajo Canyon is threaded by an unpaved maintenance road today, and it could at some point in the future be paved over by an extension of four-lane Navajo Road from College Avenue to Waring Road at Interstate 8.

The gated (but open to pedestrians and mountain bikers) access road into Navajo Canyon starts from a parking lot at the end of Easton Court in Allied Gardens and descends about 1 1/2 miles to Adobe Falls Road near the Waring Road/I-8 interchange. On our way down this road, our astute guides pointed out specimens of coast barrel cactus and California spine bush (both endangered species), as well as the more common assemblage of sage, lemonade berry, toyon, prickly pear cactus, and coast cholla cactus that is typical of the sage-scrub plant community coating coastal hillsides throughout our county.

Native willows, cattails, and a couple of cottonwoods could be seen crowding into the bottom of the canyon, where a small stream trickled. But so, too, did nonnative fan palms, pampas grass, eucalyptus, and two kinds of pepper tree. These unwelcome if not-bad-looking interlopers were disparaged for their invasive behavior; I could only agree with that, having seen the canyon years ago in a more pristine native state.

Our watch for wildlife was highlighted by the impressive vertical flying maneuvers of an Anna's hummingbird in the throes of a mating dance.

I'd recommend the easy ramble through Navajo Canyon to anyone interested in seeing a better-than-average example of an urban canyon and in understanding the challenge of keeping utility infrastructure to a minimum in open-space areas. To learn more, call Liz Freirich at the Canyons Campaign, 619-299-1741.