Let’s start thinking about water!

Water and the White Shaman

I had this paper in the queue before Texas Monthly published an article this month about the controversy surrounding both the conclusions and one of the authors, Gary Perez. I met Gary last fall at a Barton Springs event where he came to give an invocation (but declined, due to an ongoing battle with San Antonio over saving trees downstream of the come-again-and-mostly-go-again San Antonio Springs) followed by my performing a piece titled “recharge/discharge” on the theremin (which is a good instrument for a [recovering] groundwater modeler, since there’s a lot of arm-waving involved).

Gary is the one who noticed that an element of the White Shaman panel, a stunning 4,000-year-old pictograph overlooking the Pecos River near its confluence with the Rio Grande, looks curiously like the Balcones Escarpment with its major springs (see a travel log of my visit to the panel here). This interpretation is, of course, speculative since the artist is unknown and unavailable for a beer. But as a hypothesis, why not? A Texas A&M University professor proclaimed that the idea didn’t make sense: given the large springs in the area of the White Shaman site, why would the Native Americans have left? However, he seems to have neglected the fact that Coahuiltecans were nomadic hunter-gatherers in a desert climate. There were Indian trails connecting these springs long before the Camino Real (and later I-35 and Hwy-90) came into existence. Hopefully, further exploration of religious symbolism in the art will provide a further test of what it all means.

Small flows with big benefits

Ermann and besties examine whether relatively small increases in freshwater inflow can significantly improve estuarine health, focusing on the Guadalupe Estuary (San Antonio Bay) and the Lavaca-Colorado Estuary (Tres Palacios and Carancahua bays) along the Texas coast. Estuaries depend on freshwater inputs to regulate salinity, deliver nutrients, and sustain benthic communities, yet diversions and reservoir operations often reduce inflows. While prior research has emphasized large-volume inflow requirements, this study evaluates ecological responses to more modest flow changes.

The results demonstrated clear linkages between freshwater inflow, water quality, and benthic conditions. Salinity was inversely correlated with discharge, while nutrients (silicate, nitrate, and phosphate) increased with inflow. Distinct benthic assemblages occupied oligohaline (low-salinity) and mesohaline zones, with optimal community abundance and biomass observed at intermediate salinities (approximately 2–10 practical salinity units). Even modest increases in freshwater inflow—on the order of 10% of the average monthly volume—were associated with measurable improvements in estuarine conditions. However, larger systems like the Guadalupe Estuary required greater flow additions to achieve similar benefits compared to smaller systems such as Carancahua Bay. Ermann and pals conclude that hydrological conservation and restoration projects delivering small, targeted increases in freshwater can yield positive ecological outcomes, particularly in upper estuarine reaches. This finding has important implications for environmental flow management, suggesting that even limited restoration flows can help sustain biodiversity and ecosystem function in freshwater-stressed estuaries.

An acronym from hell

I have to confess that I chose this paper in large part because of the longest (albeit hyphenated) acronym I have ever seen. Look at it! A glorious total of 18 characters, including three hyphens and one en dash! Onchoke and amigos examined three common pesticides—carbaryl, chlorpyrifos, and paraquat—in wastewater from the Nacogdoches Wastewater Treatment Plant in East Texas. These chemicals are widely used in farming and landscaping, but they are toxic to people, wildlife, and waterways. The researchers developed a simpler, more affordable test to measure these pesticides, using a method called solid-phase extraction and high-performance liquid chromatography. When they tested water from different stages of treatment, they found that all three pesticides were still present, sometimes at relatively high levels. Worryingly, the treatment plant was able to remove only a small fraction: less than 1% for carbaryl, about 7% for chlorpyrifos, and around 36% for paraquat. This shows that conventional wastewater treatment does not do a good job of removing these harmful chemicals.

Oh! And the SPE-RP-HPLC–PDA-FD method stands for the solid-phase extraction, reversed-phase high-performance liquid chromatography, photodiode-array, and fluorescence detectors method. Whew!