For roughly 30 miles along this stretch, the highway runs across the band where the Edwards limestone reaches the surface and creeks vanish into it. Streams draining off the plateau lose their water into sinkholes, fractures and caves here rather than running on to the coast, and that water reappears at Comal and San Marcos springs and in the wells that supply about two million people. The zone is why a spill on this road is treated differently than a spill 20 miles east, and why the recharge area has its own development rules.
Getting there
29.6500, -98.3200
Locations are approximate and may be inaccurate, on private land, or otherwise inaccessible. Check before you travel.
Hear it from the road
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