Location: Rock Island, TN, just north of McMinnville
Access: From I-24 at Cookeville, head south on US 70S for 30 miles, then turn left (north) on TN-136 (Rock Island Rd). Continue for 1.2 miles and turn left onto TN-287 (Great Falls Rd), which takes you under a black metal arch. Continue 1.5 miles to the bridge over the Collins River, and you've just entered Rock Island State Park. At this point, you're in, but to get to the main operations center with maps, continue 1.4 miles on Great Falls Rd from the bridge, and turn right on Beach Rd at the big Rock Island State Park sign, and park HQ is shortly on the right. 
Fees: None
Dogs: OK on leash
Weather: Current National Weather Service forecast

The power generators are not located at the dam, but rather are downstream from the dam from which backed-up water is channeled through an underground aquaduct. Just downstream from the dam, water backed up from the Collins River in Great Falls Reservoir seeps through about 500 feet of limestone and falls into the Caney River Gorge below the dam, forming Twin Falls, which is a bit of a misnomer since there are many more than 2 streams of water cascading down, and no two are alike enough to be called Twins. The individual streams of water merge together to form something more like a sheet of a waterfall that stretches for almost a hundred. In fact, the entire cliff that forms the south side of the Caney Fork Gorge leaks water from the reservoir to some degree. It is an impressive sight, especially in winter when every miniscule trickle freezes and becomes very obvious. Looking at a map of how close the Collins River veers to the Caney Fork, it seems inevitable that within a few tens of thousands of years, it will break through the limestone right there at the falls and shorten its path by a couple of miles. 

Almost immediately below the dam, water reaches the level of Center Hill Lake, the next reservoir along the Caney Fork River, impounded by the massive 260-foot Center Hill Dam some 60 miles downstream. When the powerhouse is generating, massive amounts of water come flying down the gorge, creating whitewater rapids and churning, swirling water smacking rocks and trees. Every time I've been to the powerhouse area, I've encountered kayakers, either in the churning water, or hanging out waiting for the powerhouse to generate so the water level will rise and produce rapids. When the powerhouse is not generating, the gorge is filled only with a shallow trickle of water, and is very peaceful. 

Rock Island State Park surrounds the Great Falls Dam and the shores of the Caney River immediately below the dam. Apparently the area is named after an actual island that existed at the confluence of the Collins and Caney Fork Rivers but was inundated by Great Falls Reservoir. It’s not a large park (883 acres) and the trails are not long or strenuous, but since we live only about 10 minutes away from it, I find myself hiking there pretty often. 

There are 7 hiking trails in Rock Island State Park, detailed below. The map shows the longer trails only.

Blue Hole Trail
Trail Length: 0.5 miles one-way
Difficulty: Moderate
Trailhead: Blue Hole Picnic Area

10/29/2010
Andra’s parents, Bob and Karen, visited in October. The five of us (Ada had no choice but to come along) had a picnic at the Blue Hole picnic area, where they have several tables and grills tucked amongst the trees, along with an oddly spacious outhouse. It was a cool day, but sunny and calm. All in all, a perfect fall day. We had a lunch of sandwiches and sliced apples, and afterwards decided to head down the Blue Hole Trail to the Caney Fork River below. 

The trail down the hillside to the river is very steep, and not very well maintained. Starting out, there are some stairs and a wooden rail to help you down over the wet, slick rocks, but that peters out pretty quickly, at which point you’re on your own. The trail heads down the same north-facing cliff face that Twin Falls seeps out of, and the same seeping action is evident here, as numerous small seeps and a large waterfall spill out of the rocks and sluice water all down the rocky cliff face under the trees. The rocks are slick with moss, and wobbly too. As I was carrying Ada in the backpack, I was super careful, and all was well. My feet got wet in a hurry, but other than that it was a nice walk down. The spectacle of so much water sliding out of the rockface is really worth the hike. The route is in complete disrepair, and it’s not clear that there are any plans to spruce it up at all. It’s fun, but for most people it might be a bit too wet and wooly.

Near water-level, the terrain leveled off and though it was still rocky, it was quicker going. We picked our way along the rocks through the trees to an open rock field on the edge of the water, a deep section of the river where the ripples smooth out and lay still called Blue Hole. Vertical cliffs twenty feet high bordered the south side of the river, with more forest above that. Green vegetation ruled the gorge, and in warmer times, I’d be tempted to plop right into the deep water. Ada looked all around at the green trees and blue sky, and really seemed to enjoy the view. From the edge of the water, there’s not really anywhere else to go, as the terrain along the river is extremely steep and slippery. It’s a short hike, but the destination is a good one. 

1/16/2011
This is the only trail on the north side of the Caney Fork River in Rock Island State Park. The trailhead is directly across from the powerhouse several hundred feet back from the water. There are a couple of parking areas a couple hundred feet apart at the end of PowerHouse Road. From either one, it’s a short walk down to the Caney Fork River and the best viewing spot for Twin Falls, the result of water backing up in Great Falls Reservoir on the far side of the peninsula that separates the Collins River from the Caney Fork, and seeping through the limestone to come spewing out of the cliff face. 

I checked this trail out for the first time in January after a brutal cold snap that left frozen water everywhere. In addition to the snow on the ground and in the trees, every seep from the gorge wall was frozen and silver, creating a winter wonderland. Twin Falls was roaring, sending an anarchy of tumbling water down the cliff and into the river gorge below. The powerhouse was not generating, so there was little water in the gorge, just a light, green trickle heading downstream.

Walking downstream along the riverbank, I encountered several kayakers carrying their boats up to the parking area. One of them had a little white dog in a green sweater tagging along. I asked the guy if the dog kayaked with him, and he said yes. Awesome.  There is a very well-defined path that hugs the riverbank, and I kept on this path, passing by an offshoot that headed up to the other parking lot. Continuing downstream, I came to Little Falls, a small waterfall that has a cave behind it that you can walk into, and come out on the other side of the falls. It’s a neat, short side trip. 

Blue Hole was the next feature along the trail, a deep calm pool of water in the gorge that is not easily accessible from the north side, but is easy to get to from the Blue Hole Trail. Around this time the trail began a short loop, and at the fork in the trail, I headed right, following the cliff face through thick trees. I passed by an uprooted tuliptree with a mat of thick roots about 8 feet in diameter on display. Having just spent several days measuring girdling roots on young maple trees at work, I took time to examine the way the large roots crossed and fused with each other to make an intricate lattice.  The trail began to curve back after a bit, and I noted that a spur trail led down to a small beach along the water, but I didn’t head down there. Instead, I continued on the trail as it circled back around and began heading upstream along the top of a 20-foot cliff that plunged vertically into the green water below. Across the river, thousands of icicles exuded from the rockface, and about once every three minutes, a resounding splash echoing through the gorge indicated a large chunk of ice letting go of the rock and crashing into the water below. 

The loop trail rejoined the main trail at Blue Hole, and from there I simply retraced my steps upstream, and took the shortcut trail to the upper parking lot.

Collins River Loop
Trail Length: 2.5 miles (sign says 3 miles, but my GPS says differently)
Difficulty: Easy
Trailhead: Across from the power generating complex on Great Falls Rd

10/16/2010
This longest trail in Rock Island State Park is also my favorite, principally because it is the only trail that affords enough distance to feel like a hike, rather than a stroll. Consequently, I return to this one most often of all the park’s trails. Andra, Ada and I hiked it together the first time, in August. The deep shade of the hickory/oak canopy didn’t completely shield us from the heat of the day, and I sweated buckets, even though the trail was flat and easy. 

The trail is very straightforward, being a simple loop around the peninsula that follows the Collins River for about a mile and half before it joins the Caney Fork River just above the dam.  Houses and docks dot the far side of the river, but the park side of the river is pristine and calm. The trail is wide enough for two people to walk abreast for almost the entire length. Several members of the Cunningham family are buried just alongside the trail, and the oldest and largest marker of white marble is plainly visible from the path, though I passed by it half a dozen times before noticing it. There are several large black walnuts along the trail near the bridge, and also near the picnic table at the trailhead, which litter the ground with hundreds of tasty nuts in the fall, if you care to take the time to crack them.

Eagle Trail
Trail Length: 0.7 miles one way
Difficulty: Easy
Trailhead: Start at either the Blue Hole or Badger Flatt Picnic Areas

10/16/2010
This short trail runs from the Blue Hole Picnic Area to the Badger Flatt Picnic Area. Andra, Ada and I hiked this one on a nice late summer day when the trees were still lustrous green, but the temperature hinted at fall. The route is completely shaded by large hardwoods, with plenty of ferns in the undergrowth, and is far enough back from the river that it only occasionally comes into view. Like most of the trails in Rock Island State Park, it offers nothing dramatic, and doesn’t lead to any particular destination; just a nice stroll through the woods.

Moonshine Trail
Trail Length: 0.3 miles one way
Difficulty: Easy
Trailhead: Start across from the tennis courts parking lot, or from Campsite 39

2/12/2011
It looked like a nice, warm day, but it just wasn’t. No matter how much I wanted it to be warm, it just wasn’t going to warm up. The sun was out, the sky was blue, and it was only 48 degrees at 2 in the afternoon. We drove over to Rock Island for a short hike and checked out this little jaunt. We parked next to the tennis courts, which appear to get virtually no use, and strapped Ada into the babypack before heading across the road to the signed trailhead for the trail. I hadn’t anticipated the slick muck we encountered on the trail, though since it snowed just 2 days ago, I should have. We slipped and slid on the greasy surface, and finally I just started walking in the leaves parallel to the trail and had an easier time of it. There are lots of very large tulip trees right along the path, and near the beginning of the trail there’s a very cool American Beech with a massive side branch that hangs out in the air like a teapot handle before rising straight up, making the tree look strangely tropical. The trail advertises an old moonshine distillery, and the cinderblock square in the creekbed must be the still, as no other manmade object is visible along the route. It wasn’t impressive at all, just an old stack of bricks. Further down, the reservoir came into view, as well as the boat ramp. Then we reached the campground. Very short trail. It only took 10 minutes to walk, even stopping to take pictures. It was so muddy, we decided to return to the car via the road, completing the loop of 0.6 miles. I was disappointed since the trail had advertised half a mile, and I was hoping it might be a bit longer than that. As it is, there’s really no point in hiking this little trail unless you happen to be camping at the campground and are looking for an after-cookout stroll. Since it was so chilly, we decided to not subject Ada to any more cold by hiking the Collins River Loop, and simply drove home. Yep, a pretty ignoble hiking trip, but you have those sometimes.

Old Mill Trail
Trail Length:  Less than half a mile one-way to the gorge bottom, with lots of space to wander beyond
Difficulty: Moderate
Trailhead: Park at the end of the Old Mill Parking Lot on Great Falls Rd, which is the first lot on the right after you pass Great Falls Dam, and is next to the obvious, large brick mill that sits just a couple of feet off the right side of the road.

1/30/11 
Andra and I decided to explore the Caney Gorge below the dam, but above the powerhouse, which you can do by parking at the Old Mill Picnic Area (next to the Old Mill) and walking down a steep, but very short trail to the gorge. From the top of the trail you can look downstream and see Twin Falls, at least in winter when there are no leaves on the trees (in summer, it’s a bit tough to see). I had Ada in the backpack, so I was very careful going down the slippery, wet steps to the gorge. Along the way, there’s a really nice waterfall to the left, but the mossy rocks are slick and it’s not speedy going to get around down there. We made our way through the jumble of slick rocks and out onto the flattish slabs of limestone, pocked with little craters where water collected and algae grew. The gorge is several hundred feet wide, though a deep crack in the middle where the Caney River still flows presents a big obstacle to getting to the other side. We walked downstream in the gorge under a beautiful blue sky and enjoyed the amazing warm temperature that hovered around 70 degrees. It’s always so nice to get that first really warm day after a long, cold January!

Andra rockhopped down to the green water pooled below, and walked along the edge of the hole, which looked like a fantastic swimming spot, while Ada and I watched from the limestone ledges above. Downstream to the west, the powerhouse was clearly visible, as was Twin Falls. A couple of people were milling about on the rocks on the opposite side of the river near the large warning banner above the powerhouse. It was a nice, quiet spot. 

Once Andra got the fill of the water-watching, we all marched back upstream on the barren rock of the gorge bottom, and then hiked up through the trees on the slick stairs to the parking lot, and zipped off to do another trail.