Falmouth Spring is a karst window. At the head of the karst window, the pool measures 87 ft (26.5 m) north to south and 81 ft (24.7 m) east to west. The depth is 39 ft (11.9 m). The water discharges from a conical depression. The bottom is sand and limestone. Water is fairly clear, greenish with tiny suspended algal particles. The bottom and sides are thickly covered with dark green filamentous algae. Limestone is exposed along sides. High sand banks rise steeply along the karst window to 25 to 30 ft (7.6 to 9.1 m) above water level. Surrounding high ground has mixed hardwood and pine forest. The run flows 450 ft (137.2 m) northeast until disappearing into a siphon. The east side of the karst window has a wooden boardwalk leading down to spring and a foot path along the run.
Falmouth Spring is 10 miles (16 km) northwest of Live Oak. From the intersection of I-10 and US 90 northwest of Live Oak, travel about 2.9 miles (4.7 km) northwest on US 90. Enter the Falmouth Spring Recreation Area at the SRWMD sign on the south (left) side of the road. The spring is west of the parking area and is accessed by an interpretive hiking path.
I expected something rank when I looked at the satellite view; it was dark, heavily wooded, and with a name like "foul mouth", it wasn't looking good. However, I'd be lying if I said this wasn't my favorite memory from the entire trip. We parked at the top of the landing and scaled down the boardwalk to the karst window (http://en.wikipedia.org/wiki/Karst_fenster).
This spring is one of those "sum of its parts" locations that just feels so nice regardless of its individual values. The water visibility was pretty bad. I took a few snapshots of the rise but it was nothing but a solid slightly-tannic scene. It's also in a small ravine, so the sun doesn't reach much and the canopy is thick. It's also a fair bit creepy. The spring water emerges from a dark shaded area; I tried to swim into it but I lost my appetite for adventure fairly quickly. About 200ft down the run the water abruptly enters another cave, and given the speed of the water, I didn't want to get anywhere near the hidden sinkhole.
Despite all that, it was very quiet and pristine. The transparent water gurgled down through the rocks and fallen branches in such a way that the normal soothing sound resonated throughout the area. The run was a perfect depth - about 2.5' - to allow wading or swimming. The water as always was icy cold, but the tree cover made it just a little cooler. After I'd been taking pictures from the run for about 10 minutes, the sun slid behind some clouds and the area became very chilled, almost like an AC unit kicked on. Mist/fog started to rise off of the run and within minutes, the sun came back and started lancing through the fog to create some of the most sickening sweet imagery I'd ever seen at a spring. My camera didn't do it justice (especially since the lenses kept fogging up). I ran down the bank to get shots of the sink and the trees in this state.
I wanted to stay and just bask in the privacy and peacefulness of the spring, but I had too many more to see on this trip. I don't know if I could go back with the same expectations, but I do hope I can chill in the run for an hour or so one day.