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Shell Ridge Open Space

Date: (Sat.) Dec. 11, 2021
Location: Walnut Creek, CA
Event Director:
Course Setter: Martin Kunz
Type: B; Standard 7-course event for beginners through advanced


Course Setter’s Notes

By Martin Kunz

This is probably the best time of the year to do Orienteering at Shell Ridge. The hills are covered with a fresh green carpet. The ground is soft, but not too deep. Poison Oak is still around in spots, but at least not in its juicy prime. Rattle snakes are gone to sleep, and the cattle are not out yet (as of the time of this writing​—​fingers crossed).

For a change, this year’s Shell Ridge event enters the park from the Southwest (i.e., not in the area used in previous years). As much as possible, please use the parking at the nearby Walnut Heights Elementary School (4064 Walnut Blvd, Walnut Creek, CA 94596), and try to avoid clogging the neighborhood streets near the trailhead. The Start and Finish are very close to the Sutherland Drive Trailhead, which is only a few 100 meters from the school.

Note: There will be no toilet at the Assembly/Registration/Start/Finish area. Please use the restroom facilities at Walnut Heights Elementary School (where we also ask you to park). Please do not do #2’s in the park.

Courses

The short beginner courses will visit the fairytale-like Indian Creek Trail, while the longer courses make use of the fine-structured topography in the North and East, as well as the prominent hills with the fossil-packed limestone rocks that give this open space (and its map) its name. For the longer courses, expect both fine-navigation tasks and route-choice puzzles.

Here are the course details:

    Navigation     Course    Length    Climb   Controls
    Beginner       White     1.5 km     55 m       8  
                   Yellow    3.1 km    100 m      10
    Intermediate   Orange    4.6 km    290 m       9  
    Advanced       Brown     3.4 km    165 m      10  
                   Green     5.4 km    380 m       9
                   Red       7.2 km    505 m      15
                   Blue     10.1 km    625 m      22

Note: There will be water on only the Green, Red, and Blue courses.

Some Comments on the Map

The map scale is 1:10,000. The contour interval is 4.9 meters (16 feet)!

The map has evidently undergone several revisions by different mappers, which resulted in some inconsistencies. These are minor, and I tried to clean them up in the vicinity of the controls used.

The main inconsistencies are in the use of the green and brown ×s, green dots, and the mapping of individual trees. In parts of the map, a brown × (according to the International Specification for Orienteering Maps [ISOM], a “special landform feature”) is often used to map a dead tree on the ground, and the green × is used for a dead tree still standing. Single trees are often, but not always, mapped as a small white patch of forest.

The symbols for boulders (black dot), boulder cluster (large black triangle), and boulder field (small black triangle) also seem to be used interchangeably.

Most ponds are dry during most of the year, although they have been filled during the recent atmospheric river. The water is foul though, so don’t go near it.

Deer trails had been mapped extensively in parts of the map, and the ones I visited were mostly changed, gone, or replaced. I took them off the map, since they were inaccurate (blame the deer and mountain bikers, not the mapper), and made the map confusing to read without adding any useful information.