Clopper Lake

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April 23

Seneca Park streamOrienteer on relatively new terrain near the Clopper Lake section of Seneca Creek State Park (Gaithersburg, MD), thanks to an expanded map from course setter Nadim Ahmed. There will be eight courses to choose from (2 beginner, 1 intermediate, and 5 advanced), and very complete course notes are now posted below.

As with all QOC events, we will have free newcomer instruction at this event. A QOC member will show you how to read a map, teach you how to use a compass with your map and give you hints on how to navigate your choice of course. Besides that, just wear a smile and the clothes you would for a hike or run in a local park. Bring a compass, if you have one, or borrow one at the event. And dogs (on leash) are welcome at Seneca Park too. Driving directions are below; for those using ride-sharing services, this event is within the DC metro coverage area of Uberpool.

Event timing will be standard: register anytime between 10:45 - 1:15, start between 11 - 1:30, and be back before the controls start being picked up at 3pm.

Other event notes:

  • Park entrance fees are $3/per person or $5/per person (MD vs out-of-state residents) at the entrance gate. Children in safety seats enter at no charge.
  • Green, Red, and Blue courses will explore a new area of the State Park south and westward of Riffleford Rd.
  • Registration will be at the Blue Jay Pavilion, towards the west end of the parking area shared with the Nuthatch Pavilion. Carpooling is encouraged. A park map is here; the Blue Jay Pavilion is at the left (west) edge, towards the bottom.
  • If we overflow the parking lot, we are allowed to park along the NW side of the road leading to it, i.e. the right hand side of the road as you drive in.
  • Map scales will be 1:5000 for white and yellow courses, 1:7500 for beige and brown, and 1:10000 for all others.
  • Bathroom facilities are located at the east end of the parking area.
  • Dogs are welcome but must be on a leash.
  • There is a disc golf course in this park (see the DNR map cited above for it's location).


Seneca Creek State Park, Clopper Lake, Blue Jay Pavilion, Gaithersburg, MD (Classic)

RegistrationNo advance registration required. Just show up and have fun!
Start TimesYou may start your course at any time during the start window listed below for your event.
ScheduleSunday, April 23
11:00 am - 3:00 pmClassic:
Event Director:Mark Mace
Event Director:Patti Mace
Course Designer:Nadim Ahmed
Location Details

Seneca Creek State Park
Clopper Lake, Blue Jay Pavilion
Gaithersburg, MD
Google Map

From I-270, Gaithersburg, MD, take Exit 10 west on Rt 117/Diamond Ave. which becomes Clopper Rd. Go west about 2 miles and turn left into the park entrance. Proceed straight passing the first intersection and a parking area. If the event is being held during a time of year when it's collected, pay $3/pp or $5/pp (MD state, vs out-of-state) at the entrance gate, then bear right at the next intersection. You may see the lake on your left. After about 0.5 mile, just before the road crosses the dam, turn right onto the small road heading to the Blue Jay and Nut Hatch Pavilions. Both pavilions are in the woods south of their shared parking lot; Blue Jay is to the west. Please carpool if possible. If the lot is full, you may park on the NW shoulder of the road leading to the parking lot.
Course DetailsClassic
Course NameLength (km)Climb (m)No. Controls
White 24011
Yellow 2.43510
Orange 4.913511
Brown 3.610010
Green 6.213515
Red 7.727513
Blue 9.629521
Course NotesClassic

New areas have been mapped. The Blue, Red and Green courses go into them. A large area in the far southwest for the Red and Blue courses was mapped with the green symbol, due to tree blowdown. Two large rough open fields that Red and Blue runners may choose to cross do have thorns—these are mapped with the vertical green slash symbol.
Many parts of the map have changed and have been updated.
The White and Yellow courses go off trail. Both follow along Great Seneca Creek. The Yellow course goes further off trail along a field edge for high tension power lines. Most of the off trail travel has excellent visibility. Some intermittent fishing trails can be followed along the creek banks. The White course finishes off-trail following an uphill route away from the creek and back to the Finish that is marked by streamers.
The crossing symbol is used to show crossing points both under and over Great Seneca Highway.
Depending on route choices, Orange and all of the advanced courses may encounter sewer line and water management construction. What’s known of the construction as of this writing has been mapped. A sort of temporary road bed made of boards, and surrounded by chain link fencing runs through most of the Long Draught stream valley. This will slow runners who try to cross it. Some areas of the map have been marked out of bounds for the construction (2 areas fenced off near Riffleford Rd.). The vertical black slash symbol shows the out of bounds areas but one may need to look carefully to see it on the map. A water control near Riffleford Rd. is very close to some of the out-of- bounds fencing too.
Over the winter, the park has been dry. Some of the mapped water features may be dry.
As if to make up for the dryness, beavers have continued damming parts of Long Draught Creek. The pond from the dam erected just before the event last year has grown, and a new dam further upstream has been mapped with a similar long narrow pond.
Though not typically in this park any more than any other park that QOC conducts events in, ticks are active. Checking yourself after competing is a good precaution.
The park service once again did spring cleaning-up by using tractors to push brush back further into the edges of the forest and they even cleared some trees in one area. The new clearing was mapped but it may change further.
Most advanced courses and Orange course runners to a lesser extent, will cross a disc golf course. Orienteers are asked to respect the disc golfers’ use of the area. Some serious golfers enthusiastically regard it as their own—they manicure the vegetation and play it in 6 inch deep snow on windy 14 F days. Prize money competitions are held. Orienteers crossing the disc golf course should keep a lookout for flying discs, and are asked to pause when a golfer is taking a shot. Please remember that complaints could lead to QOC not being allowed to cross the area in the future. That would be a shame since the open and scattered open ground there is delightful for running. The disc golf course holes do get moved occasionally so it is possible for point features to be out of date. Many, but not all of the immovable concrete tee-off pads were mapped too.
Green, Red, and Blue course runners will have to cross Riffleford Rd. twice. Riffleford road is single lane each direction and has good paved shoulders that are sometimes used for parking. The traffic on it is usually infrequent but cars do drive 40mph in the area. Caution is needed. Even though competitors will be on the clock, one can usually run along the road when cars are present, then cross when there is a break in the traffic.
The main trail on the southwest side of the road is used by mountain bikers.

Entry FeesIndividual Entries

Note: juniors = under 21

Club Member, adult Club Member, junior Non-Member, adult Non-Member, junior
Epunch Owner $5 $5 $10 $5
Epunch Borrower $10 $5 $15 $10

Team or Group Entries

Participants are welcome to compete together as a single team entry. Teams containing one or more nonmembers are charged the nonmember individual rate. Teams containing one or more adults are charged the adult individual rate. For teams to receive member or junior rates, all members of the team must be members or juniors, respectively. Each extra team map beyond the first is an additional $2. Individuals or teams desiring to compete on a second course can do so for a reduced fee of $2/map.

Important Notes
  • At the event, we can only accept payment in cash or check; online, you may use a credit card or PayPal account.
  • If you have access to a smartphone, you may become a member at the event by joining online via this webpage (which also explains the member benefits). Membership is completely optional. If you wish to join or renew, we strongly recommend joining (or renewing) online before the event rather than at it to save time and because it's easier.
  • Most of our events use an 'epunch' timing chip for electronic timing. Individuals or groups without their own epunch pay a higher entry fee (see above), which includes the loan of an epunch for that event. Loaned epunches that are lost incur a $40 replacement fee. Epunches (also known as SI-cards or finger sticks) are usually available for sale at each event as described here.
  • Former QOC members who have let their membership lapse pay non-member fees.
  • Compasses are available at no charge, but if lost incur a $15 replacement fee.
  • Please provide collateral (driver's license or car keys) when borrowing a compass or epunch.
  • For additional safety, whistles are available for sale at $1/each.
  • Free beginner instruction is always available - just ask at the registration table.