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Bon Tempe Reservoir

Greg Ehrensing Memorial Volunteer Event

Date: Dec. 5 - 6, 2020
Location: Fairfax, CA
Event Director: - 415.456.8118
Course Setter: Dennis Wildfogel

Please note that time limits apply. Events are typically not canceled due to bad weather.

November 19th Update

All 56 spots have been claimed as of tonight! I will keep a waiting list, as we do often get a cancellation or two, so if you still want to attend, let me know and you'll be on standby.
I'll send out start times for everyone this weekend (see comments below).

Great news to report! We are now good to go for holding the first official BAOC event since the COVID-19 virus forced us to suspend events back in March!

The event will take place over two days, Saturday & Sunday, December 5th & 6th. The courses will be the same both days, so just plan on making a reservation (see below) for either Saturday or Sunday.

The Bon Tempe Reservoir is a beautiful orienteering area located on the slopes of Mount Tamalpais near Fairfax in Marin County. Bon Tempe consists of some of the finest terrain in California for orienteering: redwood covered hillsides, open grassy slopes, runnable mixed forest, and extremely low poison oak. The rangers have cleared a lot of underbrush from the hillsides, turning a lot of the map from light green to white (runnable).

As in prior years, this event will be free and restricted to club members only, with limited attendance and preregistration required. Additional provisions will be made for virus protection​—​bring your mask and prepare to stay physically distant from all event personnel.

One big difference from prior years is that we will not limit attendance to club members who have volunteered this year, but those who did volunteer at our events in early 2020 will be guaranteed a spot. All club members in good standing (dues paid up) will be eligible to participate.

Preregistration Is Required

Right now, it looks like we will be restricted to 28 people each day, with morning and afternoon sessions of 14 people each. Aside from distancing and special procedures around the E-punch table, the event will run in a very similar fashion to previous year's events at Bon Tempe. This event will provide a good opportunity for us to try out different COVID-19 procedures to see which work well, and how to ramp up to a future event where the public is invited. Unfortunately, the usual feast of holiday food has been canceled, but we may figure out something along these lines before the event!

Those interested in participating can register by either calling or e-mailing to reserve a spot. Please tell me the day (Saturday or Sunday) and time (morning or afternoon) you wish to attend, and the course you plan to complete. You can change your course later if you wish, we just want an idea of how many maps to print.

Note: I might give preference on Sunday to people who tell him they are willing to help with control pick up. 🙂

As stated above, this event is free to all participants. Well, okay, there is an expense​—​there is a park day-use fee of $8.00 per car collected at the entry kiosk. This kiosk is staffed sometimes, but usually not, so you will most likely need to use their "automated pay station" that accepts debit and credit cards, and cash up to $10 bills (but it does not return change!). That machine is about 100 meters beyond the kiosk, on the right side of the road.

Event Schedule

Here are the times for the four start windows:

Saturday: 10–11 AM and 1–2 PM
Sunday: 9–10 AM and 12–1 PM

All participants will need to start during one of those one-hour periods.

We are planning on assigning start times for everyone; not that it is really needed for the small number of participants, but to practice for future events with larger crowds.

Location in the Park

Note: We will not be using the picnic shelter as in the past. Instead, will be set up next to the parking lot for E-punch as well as the very nearby Starts.


There will be three, advanced-level courses: Brown, Green, and Red. The same courses will be used both days. Preliminary Course Setter comments are below.

Note: Beginner and intermediate orienteers are advised to not take part because of the navigational difficulty of the courses.

More Info To Come

More detailed information, especially concerning COVID procedures, will be announced closer to the event. Check back here periodically, as updates will be posted.

I'm looking forward to actually seeing some of you for the first time in what seems like forever!

Note: We use this event to remember Greg Ehrensing, a dedicated BAOC member, who particularly enjoyed this event “in his backyard”. Greg directed and course set this event several times, as well as always helping out with whatever was needed even when he wasn't on the crew that day.

BAOC Event Coordinator
(October 18, 2020)

Course Setter Comments

We’re all dying to find and punch some controls, eh? So, to satisfy that need, there are going to be lots of controls at the Bon Tempe Volunteer Appreciation Event, December 5 and 6. I mean, lots of controls:

    Course    Length       Climb       Controls
    Brown     3.7 km     85 m (2.4%)      30  
    Green     5.1 km    165 m (3.3%)      36
    Red       7.0 km    280 m (4.0%)      44

(This course data is now final.)

The emphasis throughout will be on detailed navigation, something we don’t get very much of in the Bay Area. This will be possible because the courses are using an area of the park that was unavailable to us the last time a new map was made, so that area was never thoroughly field checked. I’ve added dozens of features to the map and made scores of vegetation changes. The courses will keep you engaged nearly every step of the way. Climb is low, almost all good routes are very passable​—​so the limiting factor will be your ability to concentrate and navigate, not your physical ability. Should be fun for one and all!

Reminder that to sign up, you must contact as described above.

More info about the map and the courses will be available closer to the event.

Get yourself psyched. We may actually have some real orienteering after nine months!

Dennis Wildfogel
(November 9, 2020)

Response to a question about the courses:

"A good deal of Bon Tempe has been covered by insidious Scotch Broom, making many areas impassable. Fortunately, the area that we’re going to use has undergone considerable clearing of brush (which, I imagine, is why it wasn’t available to us for many years) and so is very passable. The large number of controls is to take advantage of all the good detail that is now represented on this part of the map, and the shorter legs are to keep you off easy routes like trails. (For any really long leg at Bon Tempe, a road/trail route is always the fastest, and what’s the point of having that?)
"These are not Sprint courses. They are full-length Classic courses with a strong Middle flavor to them."

Comment about many controls:

"Given the large number of controls, anyone doing the Green or Red courses must remember to have an SI punch with larger capacity. When I get E-punch equipment to Scott before the event, I'll try to pick up a few of the rental sticks with 64 or more spaces for punches. People who need them should let Scott know."
 Jeff Lanam

Driving Directions

The approximate coordinates for the event are 37.9485,-122.5974.

The first challenge of the event is to locate it! Due to MMWD rules, no directional signs will be posted. There are several ways to get to Bon Tempe from Highway 101 in Marin. the default route is listed here:

From Highway 101 in Greenbrae, take the Sir Francis Drake Blvd exit, and go west for 5.5 miles to the town of Fairfax. Turn left at Claus Dr (Rino gas station on the right), and then immediately take another left onto Broadway. Turn right at the next corner, which is Bolinas Rd.

Stay on Bolinas Rd for 1.5 miles. Turn left at the large, brown, wooden sign with white lettering that says "Lake Lagunitas", "Alpine Lake", and "Bon Tempe Lake". Stay on this road until you reach the ranger kiosk. Pay the entrance fee ($8 per car) at the entry kiosk or pay-and-display machine (see comments above).

News flash: A street sign has been put up for the road into the park, at the intersection where the wooden "Lake Lagunitas" sign is. The road you want to turn onto is named "Sky Oaks Rd". So, after driving 1.5 miles up Bolinas Rd, you will turn left onto Sky Oaks Rd at that sign (it's above the STOP sign for the approaching traffic), and follow that road it to the entrance kiosk and the parking lot.

Proceed on the paved road to the parking lot at the very end. (Do not turn right onto the gravel road to Bon Tempe Dam.)