Texas’ Powderhorn Ranch Purchase: Folly or Foresight?

by Paula Levihn-Coon       

Buying land surrounded on three sides by a creek, a lake and the Gulf of Mexico might seem like folly  in a time of unprecedented flooding and rising sea levels caused by climate change. But coastal experts say Texas Parks and Wildlife’s acquisition of the 17,351-acre Powderhorn Ranch near Port O’Connor was a smart buy.

This purchase, which was completed in 2018 and called “the largest conservation deal in the history of Texas” by the Nature Conservancy, makes sense because of characteristics that makes it resilient to rising seas and welcoming to wildlife.

When the state of Texas spent $34.5 million in criminal penalties awarded to it from the Deepwater Horizon oil spill towards the acquisition of Powderhorn Ranch, it made lemonade out of lemons. Augmenting the BP money with other funds, the state invested $50 million towards the purchase, restoration and maintenance of this property, a wildlife management area that will also include a state park.

“A lot of people would tell you that the BP oil spill was one of the greatest things that can happen from a conservation standpoint on the Texas coast,” said Jim Blackburn, an environmental law expert and co-director of Rice University’s Severe Storm Prediction, Education and Evacuation from Disasters Center. “It's a shame we have to rely on a horrible event like that to receive Conservation Funds. But that's kind of a reality.”

Experts agree that global warming, caused by greenhouse gases generated by human activities, is causing climate change, which is already affecting the Texas coast. Storms, like Hurricane Ian that recently devestated Florida, are more violent and drop more rain. Land is drying out because of increased evaporation attributable to higher temperatures, which can increase salinity of land and ground water in coastal areas. Sea levels are rising as higher global temperatures cause glaciers and ice sheets to melt and water to expand.

On Powderhorn Ranch, these changes are already in play. The relative sea level has risen about 20 inches over the last 100 years, as shown by historical records of nearby Rockport. By 2050, the ocean will rise another 18 inches, said William Sweet, a NOAA oceanographer who contributed to the recently published Sea Level Rise Technical Report.

By 2100, Gulf Coast sea levels could rise eight to nine more feet, conditional on future emissions, Sweet said, but “most likely” the sea around Powderhorn Ranch will be about four feet higher than it is now.

This rise is attributable to a combination of land sinking – from the pumping of ground water, oil and natural gas and the deposition of sediments in the Gulf – and sea levels rising because of  climate change.

Inundation by the sea is not a new experience for the land that is now called Powderhorn Ranch. “That has definitely happened in the past and will happen again,” said Jeffrey Paine, a hazards geologist at the University of Texas and lead author on a 2018 geoenvironmental study of the Ranch.

In 1962, storm surge from Hurricane Carla covered most of it. And 100,000 years ago, it was about twenty feet under water during the last interglacial period, when parts of the Ranch formed a barrier island.  

Powderhorn’s attributes contribute to its resilience against sea level rise and its desirability as a wildlife refuge, said Ted Hollingsworth, TPWD’s director of land conservation, whose job was to evaluate and execute Powderhorn’s purchase.

Geologically, Powderhorn’s characteristics made it an attractive purchase.  Its peak elevation of over 16 feet above sea level may seem low, but not in comparison to the rest of the Gulf Coast.  “It's a high point,” Blackburn said. “There's no question.”

Hundreds of freshwater potholes, ranging in diameter from tens of feet to hundreds of feet across, dot the property. These provide essential water for migratory birds, thirsty after crossing the Gulf; for endangered whooping cranes, North America’s tallest bird; for resident and wintering waterfowl; and for other animals.  Existing wells from prior oil drilling on the property have been outfitted with solar-powered pumps to provide water for these animals.

Running through the middle of the Ranch is the northeastern most extension of what geologists refer to as the “Ingleside sands,” a geologic formation composed primarily of sand, which is more stable than clay, which is common on the Gulf Coast. Particles of sand are larger and heavier than particles of clay, making them less likely to float away.  “Sand is pretty resilient. You can erode sand and then have it kind of migrate along the beach and then come back on shore when calmer winds and waves occur,” said Paine. “ So, it's a good thing that Powderhorn is made of sand.”

Most of Powderhorn’s shoreline gradually slopes to the sea,  which makes it less prone to erosion that if its shoreline were more abrupt. However, on the northeastern park of the property, the mouth of Powderhorn Lake, a mostly freshwater lake fed by a stream, is being eroded by wave action from large ships, causing salt water to encroach on valuable oyster beds and spawning grounds. To fix this, TPWD is spending $560,000 of oil spill money to design and build a two-mile natural breakwater to protect this resource.

Biologically, Powderhorn was “relatively intact,” said Hollingsworth. It was overgrazed by cattle and exotic game, but not farmed, like many nearby areas where rice-farming is common. Whooping cranes, which overwinter in nearby Aransas National Wildlife Refuge and whose population is expanding, had started to visit Powderhorn when the purchase was in the works.

Despite Powderhorn’s assets, the sea touching it will rise and its shoreline will recede. Some marshes will dry up; others will migrate inland. But potholes will continue to provide watering holes, sometimes flushed of salt and replenished by the increasing amounts of water dumped in them by more intense storms.

TPWD’s purchase of Powderhorn is a boon for wildlife. Restoration efforts since the park was purchased are returning it to its pre-ranching natural state. So far, about 4,000 acres have been restored to native grasslands. Once cleared of invasive running oaks, native grass seeds long stored in the soil sprouted. Since restoration efforts began in 2015, park staff and volunteers have counted 500 plant species, including 80 species of grasses, said Dan Walker, the TPWD biologist tasked with managing the property.

One day last winter, Walker spotted nine whooping cranes enjoying the bounty of the property. Critically imperiled grassland birds like quail, Eastern meadowlarks and loggerhead shrikes now call Powderhorn home. “When you open it back up to grassland, your wintering grassland birds - a highly imperiled taxa that are in big trouble -  are coming back,” Walker said.

“There's just not a whole lot of places on the coast this large that are this relatively undisturbed,” Walker said. “To have a place like that protected - that we're working on to conserve and manage and restore - it just it makes it neat.”