Nature
Addicks and Barker Reservoirs
These are reservoirs with no lake in them. Built in the 1940s after the 1935 flood tore through downtown, Addicks and Barker are dry dams — earthen embankments up to a dozen miles long that sit empty most of the time, holding parks, prairie and forest inside the pool, and fill only when a storm demands it.
Nature
Coyotes in the Bayou Greenways
The bayou corridors running through Houston are continuous strips of cover from the countryside into the middle of the city, and coyotes and bobcats use them as roads. Coyotes have expanded their range across almost all of North America over the last century — largely because wolves were removed and coyotes are far more adaptable — and they now live inside essentially every major American city.
Nature
Dwarf Palmetto in the Bayou Bottoms
The fan-shaped palms growing in the understory here are dwarf palmetto, and they are genuinely palms — one of only a handful of palm species native to the United States, and among the most cold-hardy in the world. They grow with almost no visible trunk, holding their stem underground, which is how a tropical-looking plant survives hard freezes this far north.
Nature
Houston's Bayou System
Houston is drained by roughly 2,500 miles of bayous, creeks and channels, and the defining fact about them is how little they fall — Buffalo Bayou drops on the order of a foot per mile on its way to the ship channel, so the water moves slowly and the tide is felt well inland.
Nature
Houston's Monk Parakeets
The loud green parrots around here are monk parakeets, native to subtropical South America and living wild in Houston because of the pet trade — birds escaped or released in the 1960s and 70s found the climate close enough to home.
Nature
Sheldon Lake
This lake was dug for a war. It was built in 1942 to supply water to the Houston Ship Channel plants making synthetic rubber and steel, and when the industrial need passed it was handed over and allowed to go wild.
Nature
Spring Creek Cypress
The big trees standing in the water along this creek are bald cypress, and they are doing structural work. Cypress root directly in the streambed, tolerate months of flooding, and their trunks and knees slow floodwater and trap sand, which is part of why Spring Creek still runs over clean sandbars instead of scouring to bare clay.
Nature
The Cattle Egret's Arrival
The white birds standing among cattle in these fields are cattle egrets, and unlike almost every other bird here they arrived on their own. The species is native to Africa, crossed the Atlantic to South America in the late 1800s under its own power, worked north through the Caribbean, reached Florida in the 1940s and the Texas coast in the 1950s.
Nature
The Drowned Subdivision at Brownwood
Brownwood was a waterfront neighborhood of several hundred homes that sank into Galveston Bay over about forty years. As nearby industry pumped groundwater the land dropped as much as ten feet, so yards that had been dry became tidal, streets flooded on ordinary high water, and Hurricane Alicia finished it in 1983.
Nature
The Ground Beneath Houston
There is no bedrock anywhere near the surface here. Houston sits on thousands of feet of sand and clay washed off the Rocky Mountains and dumped by rivers across a subsiding coastal plain, and the layer everything is built on — the Beaumont Formation — is a Pleistocene clay laid down when sea level was different.
Nature
The Gulf Coast Aquifer
The water under this ground arrives from the north. Rain falls on the sandy outcrops up toward the Piney Woods, sinks into the Chicot and Evangeline sands, and moves seaward through them for decades before reaching wells around Houston — which is why the aquifer recharges far too slowly to keep up with a metropolitan area.
Nature
The Houston Toad's Missing Home
There is a federally endangered amphibian named for this city that no longer lives anywhere near it. The Houston toad was described in the 1950s from specimens collected here, needs deep sandy soil to burrow into and clean seasonal ponds to breed in, and lost both to the city's growth — it was gone from Harris County by around 1970. It became one of the first amphibians ever placed on the U.S.
Nature
The Katy Prairie
The flat, treeless ground west of Houston is the surviving edge of the Gulf Coast tallgrass prairie, which once ran roughly six million acres from Corpus Christi into Louisiana. Well under one percent of it is left in anything like original condition, which makes it one of the most reduced ecosystems in North America.
Nature
The Last Unstraightened Bayou
Most of Houston's bayous were dredged, straightened and lined with concrete in the twentieth century to move water faster. Armand Bayou was not, and it is now one of the few in the region still running in its own meanders through bottomland forest and tidal marsh — close to 2,500 acres of it preserved, with alligators, bobcats and a reintroduced bison herd grazing restored prairie above the water.
Nature
The Long Point Fault
There is a fault running under this part of Houston, and it does not make earthquakes. Gulf Coast growth faults form as thick piles of sediment slump seaward, and they move by slow creep rather than sudden rupture — the evidence is offset curbs, stepped pavement and a persistent line of cracked foundations rather than anything anyone feels.
Nature
The Salt Domes Beneath Houston
Buried under this part of the city is a column of salt several miles deep. It was laid down in a Jurassic sea, and because salt is less dense than the rock piled on it, it has been slowly rising through the sediment ever since, arching the layers above into traps that hold oil.
Nature
The Sinking of Houston
The ground across this part of Harris County is measurably lower than it was a century ago. Pumping groundwater out of the sand and clay beneath the city let the clay layers compact, and the surface came down with them: between 1943 and 1973 about 4,700 square miles southeast of downtown sank at least six inches, and ground near the ship channel dropped roughly nine feet.
Nature
The Tree That Took the Prairie
The dense stands of heart-shaped leaves along these roadsides are Chinese tallow, and almost none of this landscape looked like that a century ago. The tree was brought to the American South for the waxy coating on its seeds, which makes soap and candles, and promoted along the Gulf Coast in the early 1900s as an oil crop.
Nature
The Waugh Bridge Bats
A colony of Mexican free-tailed bats estimated in the hundreds of thousands lives in the expansion joints under this bridge over Buffalo Bayou, in the middle of the city. Unlike most Texas colonies of this species, a large share of these bats do not migrate to Mexico for the winter and stay year-round, so warm winter evenings can produce an emergence too.
Nature
White Oak Bayou and the Concrete Years
This bayou was rebuilt as a drainage machine. Through the middle of the twentieth century long reaches of White Oak were straightened and lined with concrete on the reasoning that flooding is solved by moving water downstream faster — which works for the reach you armor and worsens the problem for everyone below it.
Elsewhere in Texas
Hear it from the road
Whistlestop tells you this story automatically when you drive past. No searching, no tapping, nothing to ask.
