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Shell Ridge Open Space

(Actually Diablo Foothills Regional Park)

Date: (Sun.) Mar. 4, 2018
Location: Walnut Creek, CA
Event Director:
Course Setter: François Léonard
Type: B; Full-featured, seven-course event for beginners through advanced

IMPORTANT NOTE

The Diablo Foothills event is being moved from Saturday, March 3, to Sunday, March 4.

Course Setter's Notes

By François Leonard

We will be using the cool map made by Bob Cooley, covering an area not often visited. The map is very good, particularly given the rock complexity of the terrain. Updates have been made around the control locations.

The courses are designed to maximize the technical aspect of orienteering for this terrain. Combined with the steepness of the park, this gives more climb than usual, so the courses are on the shorter side to compensate. For your information, the course setter test-ran the Blue course in 69 minutes​—​this may help you decide which course to tackle.

The Start and Finish are 250 m from the assembly area, with very little climb. All the courses use the same Start and Finish. The start triangle will be where the maps will be handed out, and where the START punch will be located.

There will be water at control locations on all the courses.

The schedule for the event is shown on the main event page. In particular, note that the courses close at 2:00.

Path Closure Due To Erosion

Because of a mud slide, the park has closed a trail and a steep area around it (see pictures at the right, which you can click on to see larger images). We have used the forbidden, pink-X symbol along the trail and in the nearby area to indicate that this trail must not be taken, and the area must be avoided.

We put a control on the White and Yellow courses right at the beginning of the trail to force participants to not keep going on that trail. Runners on the Orange course should also not take the trail, although no control is there for them at the beginning of the trail. Runners on the advanced courses may come to this trail from a perpendicular direction, and want to take the last part of the trail, which is forbidden; we left an open segment on the trail (i.e., no pink Xs) where it is possible to cross the trail and go to a lower trail.

Also, not far from this area, there is a main trail that encounters a fence with a gate (not pictured). This gate is not mapped (and it would be difficult to see on the map if it were), so we added the word "gate" on the map near the location of the gate.

Courses

Here is the course information:

    Course    Length    Climb  Controls
    White     2.7 km    150 m      9  
    Yellow    3.0 km    150 m     11
    Orange    3.1 km    250 m     11
    Brown     2.7 km    225 m     11
    Green     3.6 km    265 m     15
    Red       4.2 km    305 m     14
    Blue      5.1 km    385 m     25

Additional Notes

• The park is steep. There are large rock cliffs that are dangerous. Please be careful. See note below regarding small trails.
• The maps will be printed at 1:7500 to facilitate reading the details.
• Part of the map has not been field checked. This is indicated by a continuous, pink-line boundary. Some of the controls could be close to this line, so be careful about relying on features past this line.
• There are numerous narrow broken trails. Most are mapped, but some may not be. Due to the steepness of the terrain, these trails can be useful.
• There are many controls close together, sometimes on similar features. Check your control numbers carefully.
• There is some peppered poison oak throughout. At the time of writing (late February) it is mostly ankle-high sticks with some small green leaves. All of the controls can be approached on a line that does not go through poison oak.
• Lone trees are mapped as a white patch, presumably because they have a large enough crown to occupy some area. Fallen trees or tree remnants are mapped with a green ×.
• Rock features require a special discussion:
  • It is recommended that you review how boulders, boulder clusters, small cliffs, large cliffs, and bare rock are represented on an orienteering map.
  • For example, a small passable cliff is mapped as a solid black line. The length of that line can be very similar to the length of the dashes used to map small trails.
  • Did you pay attention to the previous point?
  • Another example: A long solid black line represents a cliff. By looking at the contour lines it is usually obvious in what direction the cliff face points. However, in some cases it is possible for the black line to be "cliffy" on both sides.
  • Were you awake when you read the last point?
  • Boulders can have asymmetric shapes, such that their height appears different depending on which side the boulder is approached. This can be exacerbated if the boulder is on a hillside. For example, one of the control locations is a boulder that is 1 m high on the side where the control is located, and 3 m on the other side. This is indicated as "1×3" in the control description. Other cases are not as extreme, so there we indicated only the one size that seemed most relevant.