It took us just three days to trace the Colorado River from its source to its mouth … by car and on foot … in part because we know the waterway well. Or at least we thought we did. Like the Brazos basin, the Colorado’s drainage area encompasses scraggly draws that extend well into New Mexico. Also like the Brazos, its wet sources derive from springs either on the Llano Estacado or amid the Caprock cliffs that lead precipitously down to the rolling plains of West Texas.

Joe Starr and I – now practiced river-tracers – searched for evidence of the upper Colorado around the severely flat farmlands of Lamesa, which lies 90 minutes or so south of Lubbock.

No such luck. So we descended the Caprock canyons to ranch roads until we discovered a gully that looked suspiciously moist. It lay amid mesquite scrubland dotted with oil pumps. Not long after passing specklike Vealmoor, and after turning north on FM 1205, we spotted two fresh items: a puddling Colorado (finally) and an oil rig fire in the distance, throwing up a geyser of blue-gray smoke.

Next up: unheralded lakes. The deserted recreational areas on Lake J.B. Thomas left us to birdwatching. One can imagine the number of desert-drained avians gathering on the shores, even as late as midmorning.

Below J.B. Thomas’ earthen dam, we swiveled down to Colorado City, a railroad town of past prosperity now split between grand old homes and newer junkiness by the tracks, highways and the sad-looking river.

Narrow Lake Colorado City serves as a cooling pond for a hulking energy plant. We headed south to the E.V. Spence Reservoir. The land there is rugged and wild.

The lake itself was a revelation: two shades of sapphire on a clear day, and mobbed with white pelicans, grebes, coots, cormorants and other birds framed by limestone ledges and distant buttes. (Because of exceptional droughts, Spence has recently shrunk to virtually nothing.)

In Bronte, we stopped at a supermarket where a goth girl with streaked hair kindly helped us restock our supplies. Yes, goth, even in Bronte. (Nearby is the similarly literary Tennyson.)

We picked up the river through large and bustling Ballinger before heading into Concho County to view the O.H. Ivie Reservoir. As a lake, the Ivie is still pretty new, and development around its fringes has been comparatively careful.

The light faded as we skipped down to San Saba, our destination for the night.

This is one of our most cherished Hill Country towns, just remote enough to be spared ugli­fication and sprawlification (symptoms of greed), but proud enough to resist quaintifcation and junkification (symptoms of sentimentality and shabbiness, respectively).

We ate with the locals at Diggs Restaurant and Club just outside town (thereby enabling the sale of adult beverages, though we abstained). I doubt all but the hardiest of tourists have discovered this poorly signed place, although hunters dig right in. Fantastic food.

The next morning, after a snug night at the Hill Country Inn, we broke our fast at a doughnut shop, where a good ol’ boy bade farewell to the clerk in Vietnamese.

This was a day of closed doors that left unexpected ones open. Colorado Bend State Park, for instance, was gated against visitors. Yet that allowed us to poke around nearby Bend and the rock-strewn shores of that hamlet.

The Vanishing River Cruise was not available on Lake Buchanan, the highest of the Highland Lakes. But that left us time to wander out toward the meadows that choke the lakebed of the mostly dry upper Buchanan near Tow.

Entry to the recreation area near the Inks Lake Dam was similarly closed. So we drove around the tiny lake’s more ragged edges, ending at the virtually empty Inks Lake State Park.

Approaches to Lake LBJ were mostly blocked by rampant private development. So, instead, we perched on ledges or detoured down back roads.

Similarly, we could not make out on the map where Lake Marble Falls started and ended, therefore we tarried at a public boat ramp just below casual lakeside businesses.

The most enlightening choice of the day was taking RM 1431 from Marble Falls to Lago Vista, trailing drought-decimated Lake Travis. What a gorgeous path! Steep, green hills cascade down to a simple, two-lane road devoid of the uglification that envelops the byway from Lago Vista to Cedar Park.

Here lies the headquarters for the spectacularly wild Balcones Canyonlands National Preserve.

To the outsider, Lago Vista looks like any other traditional vacation community, with golf courses, boating facilities and subdivisions. The parks on Arkansas Bend – again devoid of human activity – were invigorating and well-tended.

We raced down the last of RM 1431, onto U.S. 183 and over to Loop 360 (Capital of Texas Highway) to climb the lookout above the graceful Pennybacker Bridge over Lake Austin.

I’d noticed people trekking to this spot hundreds of times, but never assayed it myself. Vertigo set in near the cliff edges, but we obtained dramatic shots of the bridge and lake.

Our final stop on this leg of the ColoradoRivertracing was within walking distance of our Bouldin house. We parked in Butler Park, crossed Riverside Drive, and tripped past the joggers and dog-walkers to stare up at downtown Austin.

Just the previous morning, the Colorado was a moist gulch in West Texas. Now it reflected the pinnacles of a vibrant, contemporary city, informed by, but seemingly alien to, the more slowly changing cultures upstream.

God bless the Lower ColoradoRiver Authority. If you are tracing the Colorado downstream of Austin by car, on foot or by boat, the LCRA has a map for that. Note the pictured sign at a (deserted) park near Webberville. It lists all the major spots for public access from Austin to the sea. Very helpful.

We used this information advisedly, because we knew that, once it leaves the Highland Lakes, the Colorado grows gradually broader, deeper and siltier. Not much alteration in the bankside flora either – pecans, willows, cottonwoods, to start – from Bastrop to Smithville to La Grange to Columbus.

Instead, we simply drank in the glory of the land. Stephen F. Austin knew what he was doing when he colonized the region between the Brazos and the Colorado. Sure, his settlers faced impenetrable marshes, jungle and cane near the coast, and the ports were subject to flooding, silting and hurricanes.

Yet the rolling land, high grass and oak-shrouded margins rival the Hill Country and Edwards Plateau for natural Texas beauty. No wilderness this, but man has proved a generally good steward of the land.

After Columbus, the horizon flattens out along the Colorado, dropping in elevation only slightly from there to Matagor­da. Obviously, this and the soft banks of the river invite periodic flooding, as they did in 1991 when levels reached 43 feet, according to a LCRA marker near Bay City.

Wharton is the small-town gem along this stretch. An Old South settlement devoted to cotton – and home to late playwright Horton Foote – it has avoided twee and trash, at least in downtown. The crisply clipped courthouse is the apotheosis of historical restoration.

We ate inventive sandwiches at the Tree Frog in the square. There, I could even purchase an expertly prepared decaf Americano, not your usual small-town fare.

Downstream, Bay City bustles with all the income it receives from its nuclear plants and other industry. New schools, bright signs, broad roads, all purchased with a little of our Austin Energy ratepayer money (I swear, that’s the last rivalry reference).

Not that I begrudge Bay City. I’m gratified the bucks are going for mostly worthy things. And they are doing the hard labor of generating our electricity.

Even sweeter: the efforts and dollars that went into the Matagorda Nature Park – and its well-staffed interpretive center – at the working mouth of the river.

Turns out, this mouth is artificial, like the Brazos’ and, like its sister’s, this opening is silting up. For decades, the former mouth on Matagorda Bay was blocked by a huge logjam. After a century battling the jam and then a shallow delta, in 1936, engineers built the new channel.

One story we heard, secondhand, from a longtime resident: An elderly woman had lived as a child in the plain below the logjam, and whenever they heard a distant rumble, they’d load kids, dogs, etc. onto the roof as a tsunami of logs, water and debris headed their way.

The 19th-century town of Matagorda is located on the inland side of the Intracoastal Waterway. Matagorda Beach, however, is a wide stretch of sand that curves around to the open mouth of the river.

We lingered here, watching currents run and the seabirds frolic. The sun beamed happiness as we completed our 25th Texasrivertracing.