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Bon Tempe Reservoir

Greg Ehrensing Memorial Event for BAOC Volunteers

Date: (Sat.) Dec. 2, 2023
Location: Fairfax, CA
Event Director: - 415.456.8118
Course Setter: Dennis Wildfogel
Type: C; ONLY ON SATURDAY this time; as in the past, participation is limited to only club members who have volunteered this year; PRE-REGISTRATION IS REQUIRED; NO BEGINNER OR INTERMEDIATE COURSES

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

November 30th Update

I hope you are all excited about our upcoming event, and testing yourselves on Dennis Wildfogel’s courses!
Also, the current weather forecast is for dry conditions on Saturday!
Remember, starts will be from 10 AM until noon.
Based on the experience of previous years, those arriving close to noon may have trouble finding parking in the main lot. If the lot is full, there is an overflow parking area. It is a dirt lot located on the south side of the road, just past the 90-degree bend as you approach the main parking area. It is about 200 meters before the usual parking. This lot is unsigned, but has space for probably 30–40 cars, so there shouldn’t be any trouble finding a space if the main lot is full.
As for the courses, there are still spaces available if you haven’t signed up yet! Please do so here ( by Friday afternoon, so I have time to print off extra maps if needed.
People are also encouraged to bring treats for all to enjoy. We’ll have a table available for any goodies you might bring. Come prepared to enjoy Rum Cake, Fudge, and whatever other delectables appear!
See you at Bon Tempe on Saturday!
Scott Aster
Event Director

As the year winds down, we’ll visit to our old friend Bon Tempe, land of Redwood circles, rolling, runnable terrain, and of course, the “Hillside of Death”.

Bon Tempe has a wonderful combination of rolling grassy and openly wooded hills, Redwood forests, and multiple water features. The climb is low to moderate by Bay Area standards, with minimal poison oak, which is easy to avoid. Not being open-range helps as well, both for minimizing mud areas and no barbed wire fences to wriggle under! There is infamous the “Hillside of Death” of course, but even that black hole of nastiness has been somewhat tamed by the excellent mapping updates made in recent years.

We already have our permit from the Water District! And there’s more good news: We are allowed to have more people on one day. Thus, this event will be only on Saturday.

So, I’d like to invite all club members who have volunteered in 2023 to sign up here ( if they plan to attend, so I can get a feel for the number of maps we’ll need.

As in the past, this will be our annual, free event, which is planned to have three advanced-level courses: Short (like Brown), Medium (like Green), and Long (like Red/Blue). No beginner or intermediate courses will be offered.

Update: Due to popular demand, we are adding a fourth course. This will be a short version of the Brown course, designed to minimize the climb, while maintaining the technical challenge. (Nov. 11)

While the participation limit has been increased by the Water District, there is still a maximum limit, so pre-registration is required for all participants. Please sign up here ( to let me know you’re coming and the course you plan to do. You can change your mind before the event, but we would like to get an idea of the number of maps to print.

Notes: If you already emailed Scott, please use the online form ( anyway. We apologize for changing the process midstream.
   Participation might need to be limited due to the terms of our permit.
   Preference will be given to people willing to pick up controls! 😉

We hope to be able to provide some holiday treats for all participants. Please feel free to bring something to share if you like!

More details are available below.

Scott Aster
Event Director
(November 10, 2023)


Starts will be between 10:00 AM and noon. No assigned start times; we will space you out as needed when you check in at E-punch before beginning your course.

The courses will close no later than 2:00 PM. Please make sure you are back at the E-punch table by then.

  • We use this event to remember Greg Ehrensing, a dedicated BAOC member, who died in 2018 (at orienteering age 60). Greg particularly enjoyed this event “in his backyard”. He directed and course set this event several times, as well as always helping out at this event and many others with whatever was needed even when he wasn’t on the crew that day.
  • Pre-registration is required for this event — sign up here ( Do not plan to simply show up and run. (The list of registrations is here (
  • 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 park entrance.

Course Setter’s Notes

By Dennis Wildogel

The courses for Dec. 2 (Saturday!) have longer legs and generally emphasize route choice. Forest fire mitigation work has made many areas of the park more passable. The map is more accurate than it has ever been. The ground is quite runnable. In short, conditions are excellent.

Here are the course details:

    Course       Length    Climb  Controls
    Short Brown  2.7 km    125 m      7  
    Brown        3.6 km    175 m     10
    Green        5.5 km    275 m     13
    Red          6.8 km    340 m     17

The complete Course Setter’s Notes are here. Be sure to read them.

Driving Directions

Due to MMWD¹ rules, no BAOC directional signs will be posted. There are several ways to get to Bon Tempe from Highway 101 in Marin.

The approximate coordinates for the event are 37.9497,-122.5974. You can use those coordinates, use Google Maps to get directions to "Lake Lagunitas Parking Lot", or take the route described below.

There are several ways to get to Fairfax from Highway 101 in Marin County. The quickest route is to take the Central San Rafael exit (#452, just north of I-580) and turn west at Third street (a left at the second light if you’re coming from the south, a right at the fourth light if you’re coming from the north). Follow this road for about 3 miles (it changes name three times on the way, eventually becoming Red Hill Ave) until it intersects with Sir Francis Drake Blvd in San Anselmo. Bear right onto Sir Francis Drake Blvd and stay on it until you reach downtown 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 (coffee shop on the corner) onto Bolinas Rd.

Stay on Bolinas Rd for 1.5 miles. Turn left onto Sky Oaks Rd​—​that junction is marked by a large, brown, wooden sign on your left with white lettering that says “Lake Lagunitas”, “Alpine Lake”, and “Bon Tempe Lake”. There is also a “Sky Oaks Rd” street sign on the post for the STOP sign for the approaching traffic, but that sign is much harder to see than the large sign mentioning the lakes.

Stay on this road until you reach the ranger kiosk. If the kiosk is not staffed, pay the $8 entrance fee at the pay-and-display machine 150 m further on the right. The automated pay station accepts debit and credit cards, and $1, $5, and $10 bills, but it does not make change.

Proceed on the paved road to the parking lot at the very end, following any signs to Lake Lagunitas. (Note: Do not turn right onto the gravel road to Bon Tempe Dam.) The assembly area is adjacent to the first parking lot you come to in the complex of small parking lots at the end of the road.

¹ MMWD = Marin Municipal Water District