Clopper Lake

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April 10

Seneca Park streamOrienteer on some 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 for your event.
ScheduleSunday, April 10
11:00 am - 3:00 pmClassic:
Event Director:Jon Torrance
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 2.55511
Yellow 2.47511
Orange 4.913014
Beige 2.8807
Brown 3.81408
Green 5.920514
Red 7.925517
Blue 10.434521
Course NotesClassic

The White, Orange and Beige courses are straightforward. They are in the middle of the respective technical skill levels required for these levels. The Yellow course is challenging and was set to encourage off-trail navigation by following non-trail linear features. The Green, Red, and Blue courses crisscross so runners are cautioned to be careful to navigate on the correct leg. The main challenge for all will be traversing the unfamiliar newly mapped terrain.

The Clopper Lake area and the newly mapped areas further southwest are generally very open and fun to run in. Predominantly oak forests are scattered with what are usually slower but distinctly edged pine forest areas. The primary obstacle in the forest is deadfall and that is usually mapped with the vertical green slash symbols. The threshold for mapping root stocks is usually 4-5 ft. except in areas where large and smaller root stocks are close together. There is a good variety of terrain and vegetation to navigate through. This map has more open, scattered open, rough open, and rough scattered open areas than most QOC maps. Traveling across the various rough open areas can vary a lot. Scattered rough open areas tend to be areas that you’ll want to stay out of. Part of a larger area of rough open terrain that might be encountered by Red and Blue runners in a far part of the map has thorns, whereas another nearby area crossed by Red and Blue courses has almost none. The edges of fields often have dense vegetation. Red and Blue runners will cross terrain mapped green more than other courses do—these are often reminiscent of areas in Wheaton Regional Park with bushy growth. Winter and pre-spring running is much faster throughout the park than running there in other months. Warm late winter weather is prompting growth of the ground plants that cause it to be slower for running. Hopefully the area will still be good on the competition day.

There is beaver activity in the Long Draught stream valley which is east of the start area. At least 2 dams were built. The map was updated for this on March 12th but the terrain could change. Even if you cross Long Draught Creek and stay dry, there are some other minor creek crossings. These are enough to get most people’s feet wet. No courses will cross the Great Seneca Creek which is uncrossable more often than not.

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 in in 6 inch deep snow on windy 14 F days, and prize money competitions are held. Orienteers crossing it 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 on this newly mapped ground to get out of date. Many, but not all of the immovable concrete tee-off pads were mapped too.

The White, Yellow, and Orange courses do cross the park road twice. 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, the cross when there is a break in traffic. Additionally, the main trail on the southwest side of the road is used by ountain bikers. The east-west oriented Great Seneca Hwy. bisects the map. There are only 3 legitimate ways to cross it. Two are at creek underpasses, and one is over a car bridge that leads to/from the disc golf parking lots. Selecting the right crossing will be important for your route choice.

Slopes in the park tend to not be steep but there are steep areas. Ditches and gullies far outnumber reentrants as the predominant land feature. There are some rock features: mostly small to mid-sized cliffs. Single boulders tend to be somewhat clustered. Root stocks are the predominant point features. Besides the manmade point features in the disc golf area, Red and Blue runners will likely cross a large field that was used as a rifle range. There are large standing structures there, and some unusual ground stonework. These look like curved pavement and are near the structures. These pavings are not useful for navigation. They have been covered over by grass in most areas and so they were not mapped. In the same area, the park has deposited large piles of deadfall. These are mapped with the dense vegetation symbol and the earth wall symbol—the piles are arranged linearly and are very slow to cross. All advanced courses cross flood plains. These have ditches, depressions, and a few water features. Most of it is not marshy. The ditches are sometimes well defined but some may be shallow or with varying widths and depths.

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.