Let’s start thinking about water!

Freshwater inflows to Texas bays and estuaries—a regional-scale review, synthesis, and recommendations

This open-access book is part of Springer’s “Estuaries of the World” series edited by Texas’ own Paul Montagna of Texas A&M University-Corpus Christi (TAMU-CC) and Jean-Paul Ducrotoy of The University of Hull (somewhere in the UK). Montagna and another TAMU-CC academic, Audrey Douglas, assembled 17 chapters by various authors and experts on environmental flows to the state’s bays and estuaries. The editors serve as authors or co-authors on 10 of the 17 chapters, so they weren’t simply kicking back to argue about commas.

The book is outlined well, with a logical flow of various policy and scientific perspectives, ending with a summary chapter by the editors focused on recommendations. The authors are not just estuary gearheads baying at the moon. Myron Hess provides a chapter on policy and law, and David Yoskowitz, former head of the Harte Institute at TAMU-CC and now executive director of the Texas Parks & Wildlife Department, contributes a chapter on the social and economic values of environmental flows to the coast. I’ve not read the entire book yet, but below are quick reviews of a few chapters of interest.

Climate effects on inflows

You can’t have a book about inflows without a chapter about climate change impacts on said flows. Nielsen-Gammon and Tarter provide the climatic backdrop (and “futuredrop”) on the subject, something that affects not only environmental flows but also water resources in general. Despite the certainty of increasing temperatures, the uncertainty of inflows is high, with their analysis showing equal chances of increases or decreases in total inflows. The key word is total since the models show a clear tendency toward more erratic flows with wetter wet months and drier dry months. However, the magnitude of wetter and drier is also uncertain. The authors found that runoff projections tend to indicate a decrease in median values with an increase in high-runoff months.

Similarly, they project median baseflow to decrease, although some cases showed a slight increase. They also found that, in general, inflow trends are more negative toward the Louisiana border than toward the Mexico border. They also found smaller drainage basins tend to have more negative trends than larger ones. Nielsen-Gammon and Tarter conclude that water managers should plan for a range of possible futures with more and less flow.

Summary of recommendations for the future

Montagna and Douglas helpfully end their book with a chapter of recommendations. They note that freshwater inflow standards, although widely acknowledged as important, are rare, with Texas being one of the few places on the planet with them. However, more can be done, especially since Texas established standards more than a decade ago.

 One recommendation is to develop state-wide monitoring to define estuary biologic response to inflows. Another recommendation is to expand the current two-dimensional circulation models to three dimensions. They also recommend focused protection of important nursery habitats during droughts, which will become more important with a warming climate. Finally, they recommend identifying key system metrics that can be used as freshwater inflow standards for these inherently complex systems.