She pointed at more than a hundred canoes and kayaks arrayed at one end of the narrow, clear lake.

“That’s the Texas Water Safari,” our son Keenan said just as the signal rang out and the paddlers took off, churning the water to foam. “I saw a tweet about it. They race downriver 260 miles to the Gulf of Mexico every June.”

Teelie gasped. “Can we try it?” Teelie is always up for a challenge, sometimes a little more than I’d like.

“Maybe that glass-bottom boat over there is more our speed,” I said, pointing to a long, slender boat looking a bit like a waterborne trolley.

Spring Lake is renowned for its beautiful, clear spring water. As the racers cleared the lake, the water calmed, glistening green and inviting in the sunshine. We were definitely ready to get out there. Keenan and Irene, our teenagers, headed over to join a stand-up paddling class, and Melissa (my wife), Teelie and I made for the glass-bottom boat.

Trekking San Marcos

We’d been hiking all morning, starting on the Tonkawa trailhead from the Meadows Center, which accessed the Spring Lake Preserve Natural Area. The Texas Hill Country is uniquely diverse: scrabbly mesquite, shady woodlands and prairie-grass meadow alive with false mallow, snapdragon vine, the droopy red blossoms of pineapple sage and uncountable bursts of yellow prickly pear cactus flowerets.

The stout, low-slung live oak limbs were hung with a misty halo of sunlit Spanish moss as we walked along trails rubbled with fractured limestone. This is karst country, shot through with subterranean features like Wonder World Cave, an old-school attraction in San Marcos where we enjoyed chatty, knowledgeable cave guides, a hilarious Anti-Gravity House, a 110-foot observation tower and “fainting goats.”

“When are they going to faint?” Teelie had whispered.

“Well, that one looks a little dizzy,” Irene told her, playing along. “No, he’s fine.”

It was fun.

On the preserve’s Wickiups Trail—a quick detour off of Tonkawa—Teelie climbed down into a little sinkhole, squealing happily when she spotted a Texas Horned Toad.

“You want out?” I offered my hand.

“No, Dad, I’m fine,” she grinned.

Farther west, this time on the Porcupine Trail, we found some birders watching a group of turkey vultures overhead at Sunrise Lookout.

“Look close at that one,” said the leader. “See the curved, sharp yellow beak? That’s no vulture; it’s a zone-tailed hawk.”

The hawk suddenly plunged downward, swooping through a trailside sycamore and scattering panicked American goldfinches off into the underbrush like so many black and yellow darts.

On the water

We boarded the glass-bottom boat, eager to spend time on the water. The boat was covered overhead, so we sat in a deeply shaded compartment around a long window on the floor, giving us a crystal-clear, overhead view of sunfish, channel catfish, bass, gar and even a turtle paddling along in the sun-dappled depths.

We stopped above a steady line of bubbles that the captain said marked one of the lake’s many springs. It was the springs’ reliable source of fresh water that drew Native Americans to the area nearly 12,000 years ago—making it the oldest continually inhabited area on the continent.

We glanced up to see Irene and Keenan floating by on their stand-up paddleboards. They seemed almost adrift in time themselves as the sun cast their shadows perfectly on the rocky bottom about eight-feet below them.

“I want to do that!” Teelie cried. “The water’s so clear it looks like they’re hovering in air!”

Disembarking and joining with Irene and Keenen, we collectively agreed that we wanted to keep exploring the river. We piled into the car and drove to City Park to follow the Riverside Trail, where the San Marcos River emerges from Spring Lake. People were tubing the shallow stream, plunging into deeper pools from home-made rope swings and basking in the sun on the grassy river banks.

Teelie ran happily alongside the water until we found the Children’s Playscape, a huge kids’ play area built in the style of a Western cavalry fort. She disappeared inside with Irene. Occasionally we heard them thumping and laughing past on the wooden walkways behind the palisade walls.

Finally they emerged, red-faced, happy and winded. Irene flopped down on the grass, but Teelie quickly decided she was too hot and simply had to go in the river.

We made our way downstream to Rio Vista Park, where there’s a swimming pool, picnic areas, hiking and biking trails, and kids’ play spots.

But the highlight was out in the river, where Rio Vista Falls Dam had formed a broad, deep pool busy with swimmers. The water flowed over a low spot on the dam, and laughing, shrieking people were shooting the drop-off on inner tubes and kayaks.

“That’s what I want to do,” Teelie insisted.

“All right,” Melissa said. “But that’s a fast current. Let’s get your life jacket on.”

“Will you go with me, Dad?” Teelie asked, as she buckled her life jacket.

“Absolutely,” I said. “Come on, let’s do this.”

She cheered, and we swam back upstream and then launched ourselves into the slow current. It was just deep enough to float slowly along hand-in-hand, giggling and waving at Melissa, Keenan and Irene.

People ahead of us breasted the dam and quickly dropped out of sight with a squeal, and before we knew it, we were there and over it, sliding down the slippery chute in an instant, splashing and laughing in the frothy whitewater as we kicked to shore.

“That was so cool!” Teelie gushed. “I’m so glad we came!”

“So am I,” I told her. “It turned out to be a perfect day to go with the flow.”

Discover more fun things to do in San Marcos, TX.