Monday, July 31, 2023

Enterprise South Nature Park, Mountain Biking, 7-31-23

This spring and summer I’ve had plantar fasciitis in my left foot. The symptoms from the plantar have made me cut back significantly on running and hiking, my two main forms of recreation. But luckily for me, bicycling does not aggravate the condition. Consequently, I’ve been biking regularly on the greenway in my neighborhood, and also riding on other trails around town, sometimes with my buddy DK.

While talking with DK about trails to ride outside of Knoxville, one place we both wanted to return to was the Enterprise South Nature Park outside of Chattanooga. We  remembered lots of smooth flowy single track trails, exactly the type of riding we both prefer.

Enterprise South Mountain Bike Trail Map.

One side effect of cutting back on running and hiking was that I was also getting a mild case of summertime cabin fever. So, when the next break in the summer heat arrived, I decided to head down for a solo ride. Enterprise is a Hamilton County Park located off I-75, just a little northeast of Chattanooga. It is located on the former Volunteer Army Ammunition Plant. Enterprise was created as part of the plan to revitalize the plant site after it was turned over to the City of Chattanooga. 2,800 acres of the plant site became part of the Nature Park, while another part of the property became the VW Chattanooga Plant, which builds the Atlas and ID.4 SUVs.

Development of the park started in 2006, leading to an opening in 2010. The park has hiking trails, biking trails, horse trail, and mixed use trails on old roads and newly developed single tracks. But its most unique feature is four dedicated mountain biking only trails, covering about 16 miles.

Hard hat, gloves, and safety glasses, what could go wrong?

Around that time Jean and frequently took a Labor Day weekend trip to Chattanooga, riding the old roads at the Chickamauga Battlefield site, and exploring other biking areas around town. In 2011, we stopped at Enterprise to ride the three exiting single tracks, along with a paved road loop. We had a great time on that ride, but just never got around to coming back.

After a 12 year gap, I was hoping that conditions would be as a good as I had remembered, but was braced that they would not. Mountain bike trails often deteriorate over time, as the enthusiasm for maintaining never quits matches the enthusiasm for building, and the heavy use of popular trails often degrades them. But DK’s ride there had only been a few years previously, so the current conditions should at least match his experience.

The drive down is easy. I left at 7AM and got to the visitor center 93 miles away at 8:30. The park was busy for a Monday morning with lots of cars and tons of hikers and bikers. I stopped in the VC to pick up a map, then parked at the Poe Run Trailhead where other riders were unpacking.

My plan was to ride the daisy chain of the three older loops that Jean and I had ridden in 2011, the Black Forest, TNT, and Log Rhythm trails. In 2011 the three trails were rated beginner, intermediate, and advanced intermediate, but there was little difference in their difficulty. I also hoped to add the Atlas Trail, described as advanced and not suitable for beginners. The Enterprise trails are one direction only. On a Monday ride I would be doing most loops counterclockwise. The one direction only rule is for safety, as it eliminates collisions with oncoming traffic, but it also gives riders a less crowded loop.

Just a few minutes riding on the Black Forest Trail was enough to convince me the trails were still as good as I remembered. All four are purpose built single track, generally wide enough for easy maneuvering. The trail surfaces were generally smooth, with occasional rooty areas or rock gardens, but none of those obstacles was too severe, or lasted too long. Generally, the riding was smooth enough to allow the rider to go fast enough, easily enough, to generate a nice cooling breeze. It helped that I’d gotten an early start on a cooler, low humidity day, and so was able to ride without becoming a sweaty mess. All four trails weave through shaded woods, with some sections in pine forest with deep carpets of needles.

Each trail had a few terrain features (bumps, jumps, and logs, etc.) built in, but those were always accompanied by a bypass route. The trails were also marked by color coded numbered posts, but curiously the post numbers didn’t seem to match up with the trail mileages. All the trail and road intersections were well signed.

Start of the Atlas Trail.

I was glad the CCW direction would give me a couple miles of warm up before I got to the harder and unknown Atlas Trail. The rear brake on my bike my nearly 20 year old Fischer was essentially shot, and I needed to be conservative riding with just the front brake working. A close look at the trail map shows some alternate sections of Black Forest that are likely terrain features. I bypassed those allowing me to reach the start of Atlas much sooner than I expected.

Atlas Trail (named for the explosives company, not the VW SUV) would be my only clockwise loop of the day. There was a short section of dirt road before reaching the single track. I found there were a few rough sections, and a couple short stiff climbs, but overall, the trail wasn’t significantly harder that the others at Enterprise. At the south end of the loop there’s a view of an I-75 exit, but otherwise its mostly a woods ride, with a couple of gorgeous stretches through the pines. 

At the start of TNT Trail.

At the end of Atlas, I saw my first hiker of the ride. He lived only a mile away and was curious about the difficulty of the trail. I assured him that it was only a small step from the other trails. Next up was TNT, another mostly smooth flowy single track.

Log Rhythm Trail.

Following that was Log Rhythm, the shortest of the four trails. The start of Log Rhythm was a little rough, with rock garden set at the elbow of a sharp climb. But once past the first tight corner it was back to forgiving riding. Log Rhythm is a long skinny loop. On the return leg it passes ammunition storage bunker 75. The bunkers are giant concrete domes built to store and protect ammunition. They have heavy steel truck doors and a ventilation unit on the top. The most unusual feature is the acoustics, a simple step on the floor yields a resounding boom in return. Most bunkers now seem to be closed, while in 2011 we were able to explore inside several. 

Bunker 75.

The bunkers are all numbered and shown on the overall park map (but not on the bike trails only version). Enterprise is remarkably organized; the bunkers, parking areas, and gates are all numbered. The long logs used for trick riding by the daring and skilled, and which give the Log Rhythm its name, are near the end of the loop. 

The Yellow Bunker, aka The Tunnel of Boom.

Stopping to check my map back at the Log Rhythm-TNT junction the first mountain biker of the day whizzed past me. Yeah, I had just been relieved from cobweb breaking duty! I’d be passed by only one other rider the rest of the day. There were several other bunkers alongside TNT and Black Forest on the return route. One bunker was kept open so riders can pass through the tunnel of boom.

Log Rhythm from 2011.

All morning long I’d been riding faster than my time estimates. Making the last turn back onto Black Forest I realized that I’d be done with the ride around lunchtime, but was having too much fun to want to quit. I considered adding on a ride on some of the paved hiker/biker roads, but decided to give my foot a break, and head back home. The 15.7 miles took about 3:30 including stops, pictures, and map reading. My GPS showed 1,000’ of climb, but GPS always reads too high, elevation gain is not an issue at Enterprise. 

Inside view of the Yellow Bunker.