Map & Course Notes

Updated 2/27/17 — Coincides with final notes included in your race packet. Pointed out that allergy season is here!

See Race Details for course lengths and class assignments.


Cooper Lake State Park, South Sulphur Unit, (CLSP) is a brand new map—actually, two maps, with Coyote Run on the east side of the park and Buggy Whip to the west. With a model map stuck in the middle. This will be their debut. Thank you to Orienteering USA for the map loan. Map contributors:

  • Base map: Greg Lennon, Red Arrow maps
  • Field work: Nancy Bowers (2013-2015), Tom Strat (2016), Stan Darnell (2016-2017), Jim Stevens (2016-2017), Sheila Doyle (2017)

Thank you as well to extra map and course consultant Jens Börsting of Silkeborg OK, Denmark.


CLSP is located in the borderland of the Blackland Prairies and the Oak Forest and Prairies ecoregions of Texas. The land was settled by American pioneers starting in the 1850s and farming activity began to alter the natural landscape. Over time, many of the fields were converted to pasture. Small man-made ponds (or “tanks” in Texas farming lingo) were created to retain water. Berms (or “terraces” in Texas farming lingo – not to be confused with the orienteering terrace feature) were created to stop erosion.

The berms are evident today as low undulations (too small to map) that approximate parallel contours on many hillsides. Fence were installed to keep cattle in or out of pastures and fields. As fields were plowed, the fence rows often became low linear ridges that remain today even after the fences have fallen down and the fields have grown over and returned to forest. In many places, the berms and fence rows have influenced runoff patterns and created erosion features in unexpected places.

Cooper Lake was created in the mid-1990s and CLSP opened in the late 1990s. The houses were removed and the fields were allowed to go back to nature. Over time, the fences have deteriorated leaving wire on the ground as well as a few wires up where the trees grew around them or where the posts may not have rotted yet. The ruined fences may often be just a wire or two that is a foot or so off the ground. They can be very hard to see in the woods if you are traveling perpendicular to them, but may be followed if you find them. Some, but not all, of them have been flagged for safety on the Day 1 courses. In particular, one fence has been flagged continuously as a marked route for the White course on Day 1.

Walking trails were created in the east end (Day 1) and equestrian trails were created in the west end (Day 2). As the trails are used, ruts are created, which grow into gullies, and new trails are created to replace the old trails. This leads to an intricate gully and watercourse system, including many watercourses that are not normally seen in nature – such as gullies that go down the crest of a spur where an old trail used to be.

Since the lake was created, the water level has varied. Most of the park lake shore is bordered by 1- to 6-foot earth banks associated with the shoreline when the lake is full. When the lake level drops, the gradually sloping lake bottom is exposed. As the time of this writing, the lake level is at a moderate level below the earth bank line and with 10 to 50 meters of exposed lake bottom.

The large creeks that feed northward into the lake have carved deeply incised, steep-sided gullies. When the lake is high, it extends up the major feeding creeks into the gullies, deep into the park. In the most extreme case, Finley Creek in the Day 2 area, the gullies are up to two contour lines deep, and the lake extends up a kilometer into the creek. At the time of this writing, the lake extends almost 500 meters up the  creek. This causes the longer Day 2 advanced courses to be “butterfly” courses with a mandatory crossing control at the only current safe crossing of the deep, steep Finley Creek gully.


Although there are a variety of small stones and cobbles, there are no rocks large enough to be mapped as boulders.

There are no rock cliffs in the park. However, there are a large variety of erosional landforms, including high earth banks, watercourses, ditches, and gullies. Thus, we used the following standard and non-standard mapping symbology:

  •  Years of farming, ranching, and now horseback riding and hiking have formed an intricate system of watercourses. There are so many small ditches (up to 1 meter deep), that using the standard brown dotted map symbol was confusing and impossible to read in areas with dense ditches. Thus, we used the blue dashed small stream symbol to show a wide range of water courses that can be crossed at speed (for the indicated vegetation). These include shallow reentrants, small ditches, and deeper swales.
  • Abandoned trails that are just ruts through the terrain are shown as brown dotted lines (non-standard symbol). A control clue of “ruined trail” refers to such a brown dotted line abandoned trail.
  • One- to 3- meter gullies that are narrow are shown with the standard brown gully symbol. Depending upon vegetation, they are crossable or else you only have to go upstream or downstream a short way to cross.
  • Some of the deep or wider gullies are shown with earth banks. Where they are most complex, they may be shown with contours or form-lines without hachures. Since there are no rock cliffs, we use the black cliff symbol in a non-standard way to represent an impassable earth bank and the regular brown earth bank for a passable earth bank. The brown earth bank indicates a 1- to 4-meter tall earth bank that orienteers could traverse. Taller (2- to 8-meter) earth banks that are too steep to climb are shown using the black cliff symbol. The earth banks symbolized as black cliffs should be crossed only at designated crossing points.
  • If it hasn’t rained recently, almost all of the watercourses and man-made ponds will be dry, with the exception of the larger creek gullies that have lake water backed up into them. The dry ponds will look like an earth wall with either a depression form line, depression symbol or intermittent marsh symbol. If it has rained recently, many of the watercourses, ponds, depressions, intermittent marshes, and trails may have standing water.
  • The woods include a mix of evergreen eastern red cedar, deciduous post oak, winged elm, bois d’arc, and Texas honey locust, among others. The eastern red bud blooming season starts in March. White, runnable woods are either open with native prairie grasses or a mix of small brush/trees and vines – typically low green briar.
  • Occasionally, mature stands of evergreen cedar may be fast runnable and also shown as white forest. About half of the white runnable forest is similar to what is often called the “Midwestern style” of white runnable forest. By that, we mean good visibility and running, but significant low green briar in many places (not mapped). Gaiters are essential.
  • Lighter green woods are typically oak forest with patches of taller green briar or an excess of small sapling and vines, or large cedar trees with enough low branches still intact to inhibit direct-line navigating. In low wet areas, light green often represents canebrakes. A canebrake is a dense growth of canes that is 1- to 3-meters tall, about the diameter of a pencil and fairly easy to push through, but with very low visibility. (See example below of trail through canebrake.)

  • Darker green woods can be thickets of small trees (including cedars and thorny honey locusts) and green briar that grow up as fields first turn into woodlands or more established woods with a mix of cedar and other trees with extra tall green briar. Often the vegetation is thicker at the edge of the woods where greater sunlight allows a mix of green briar, wild roses, poison ivy, and honey locust to thrive.
  • Don’t depend on thickets for detailed navigation — consider them indications of variations in vegetation density (see example below).

  • Brown Xs indicate root stocks that are at least a meter tall. We did not map the rootstocks in the lake area or within the deep gullies because they can move with each change in water level or flood.
  • Black Xs and Os indicate man-made features. The Black Xs could be green electric boxes (about 1 x 1 x 1 meters), picnic tables on concrete (free standing picnic tables were not mapped since they get moved around), trail-side benches, gas wellhead equipment, guy wire anchors for a tall radio tower, large animal traps, miscellaneous junk (including old rusty cars, old motorcycles, old culverts, old metal farm equipment, etc.), and large signs. Only the very largest signs are mapped; smaller trail signs and road signs are not mapped.
  • Black Os could be street light poles, water supply components (ranging from 0.5- to 1-meter high water system access covers to large overflow piping), birdhouses on poles (Day 1 only), pilings or buoys (including those that got stranded in the woods by the record-setting floods last year). Smaller junk less than 0.5-meter high was not mapped.
  • The black “small tunnel” symbol is used to indicate small road culverts (where quite visible or where significant water courses go under the road).
  • Orienteers may ignore any “trail closed” signs for this competition.
Course info
  • Scale varies by course: Red and Blue use 1:10000; Orange, Brown and green use 1:7500; White and Yellow use 1:5000. Contour interval is 3 meters.
  • The White course on Day 2 has a very high density of controls, including three controls that are sufficiently close together to have overlapping control circles on the map. Please be careful in checking control codes and make sure to punch all the controls in order!
  • Several sections of the White course on Day 2 take small detours off trails and are flagged by orange streamers.
  • There are many controls visible in the forest. Be sure to check your control codes! Also, there are a lot of extra, non-orienteering-related ribbons in the terrain.
  • Out-of-bounds areas (such as the camping areas, ranger homes, or the water pumping station) are marked as out of bounds on the map, with the exception of the Day 2 White and Yellow courses finish, which go along a marked (flagged) trail though two NTOA-reserved camp sites. Please respect the other camp sites and stay out of them.
  • The Day 2 longer advanced courses cross a private business road in the west end of the park. A large, temporary pipeline has been laid adjacent to the road and is not marked on the map. All of the Day 2 courses will cross a paved road to get to the finish. The White and Yellow course is flagged and will be manned by a meet volunteer. Competitors on the other courses will cross where you choose as part of your route choice. Obviously, watch out and give way to cars as necessary.
  • The Day 1 parking and Event Center is in the Gulls Bluff Day Use Area. The Day 1 competition and recreation starts and finishes are in the Heron Harbor Day Use Area. Distance from Event Center to start is approximately 300 meters.
  • The Day 2 parking and Event Center is in the Honey Creek Day Use Area. The Day 2 competition start is in the Buggy Whip Equestrian Camping Area and the Day 2 competition finish is in the Honey Creek Day Use Area. The Day 2 recreation start and finish are in the Buggy Whip Equestrian Camping Area. The walk from Day 2 parking to Day 2 start is along a road in the middle of the Day 2 competition area. Do NOT stray off of the road on the walk to the start. Distance from Event Center to start is approximately 700 meters.
  • Vegetation: Green briar, honey locust (read: long thorns), and poison ivy — they typically are less hazardous when dormant in the winter, but it already feels like spring here in Texas. Mountain cedar (actually a juniper) is a common allergen, and the forecast for next weekend is a moderate-high pollen counts. Bring allergy medicine! And wear gaiters. (Have we mentioned that?)
  • Fauna: The park is home to some venomous snakes (rattlesnake, copperhead, water moccasin, etc.), but they should still be dormant. NTOA volunteers have been in the forest >60 days since Dec 2016 and seen only one snake — non-venomous — the entire time. Destructive feral hogs are present, but you’ll likely see only the mess they leave behind. Common non-hazardous creatures include white-tailed deer and the nine-banded armadillo (NTOA’s mascot).
  • Insects: Mosquitoes, ticks, chiggers, etc., may be emerging due to warm temperatures, so you may wish to use insect repellent.
  • Man-made: Ruined fences with barbed wire lying on the ground or just a foot or so off the ground.
  • Terrain: Deep gullies with tall earth banks as previously mentioned.