think+water: Dam Failures, Lemon Water and Naturalized Flows

think+water: Dam Failures, Lemon Water and Naturalized Flows

With 38 public universities and 35 private colleges and universities in the state and many more across the country (and the world) interested in Texas, there’s a great deal of academic scholarship focused on water in the Lone Star State. In this column, I provide brief summaries to several recent academic publications on water in Texas.

Let’s start thinking about water!

Dams are coming down, but not always by choice—The geography of Texas dams, dam failures, and dam removal

Dams have been key as flood protection and water supplies but are also controversial due to their environmental impacts. Dam-building also has a long history, so there’s a range of ages and, just like the rest of us, some dams age better than others. Dascher and Meitzen provide a comprehensive overview of dams and dam failures in Texas. They found that there are over 7,000 dams in Texas with 95% of them earthen and 59% of them privately owned. Governmental bodies own the large dams while private owners claim 79% of small dams and 55% of medium dams.

The authors identified 314 dam failures since 1900 with most failing after 2000, suggesting that the rate of dam failures is increasing in the state. Greater concerns about the safety of dams is leading to removal with 50 dams removed in Texas between 1983 and 2016. Although dam removals in Texas are focused on reducing hazard risks, removals have environmental and ecological benefits. For example, removal of the dam on the San Marcos River near Ottine reconnected over 600 miles of river. I found this to be a dam good paper!

Citation

Dascher, E.D., and Meitzen, K., 2020, Dams are coming down, but not always by choice—The geography of Texas dams, dam failures, and dam removals: Texas Water Journal, v. 11, no. 1, p. 89-129. https://journals.tdl.org/twj/index.php/twj/article/view/7092

Addition Of Lemon Before Boiling Chlorinated Tap Water — A Strategy To Control Halogenated Disinfection Byproduct

I have to admit that, as a teasip, I whispered to myself “What the hell are the Aggies up to now?” after I read the title of this paper. But this is legit and especially useful and practical for concerned consumers. Chlorine disinfection, while unquestionably useful, can unfortunately lead to elevated halogenated disinfection byproducts. In 2015, almost 21 million people in the United States received tap water that failed to meet federal guidelines for halogenated disinfection byproducts. An earlier study suggested that the addition of ascorbate to tap water before boiling could significantly reduce these byproducts. Guess what lemons have? That’s right: ascorbic acid!

Liu and others used tap water “collected at a faucet in a residential area in Texas, USA” for their experiments. Boiling alone reduced the cytotoxicity index by 38% while adding lemon alone reduced cytotoxicity by 4%. But adding lemon and then boiling the water reduced cytotoxicity by 68%. When the lemon is added is important: lemon added after boiling only reduced cytotoxicity by 50%.

Citation

Liu, J., Sayes, C.M., Sharma, V.K., Li, Y., and Zhang, X., 2020, Addition Of Lemon Before Boiling Chlorinated Tap Water—A Strategy To Control Halogenated Disinfection Byproducts: Chemosphere, v. 263 https://doi.org/10.1016/j.chemosphere.2020.127954

Extension of Naturalized Flow Using Linear Regression

Naturalized flow is an input to Texas’ water availability models used for permitting, water planning, and other activities. The existing naturalized flow regime ranges approximately from 1940s to the 1990s and misses the 2010 to 2015 drought which, in some parts of the state, was the new drought of record, at least from a surface-water perspective. Zhu and others found that, for some river basins or parts of river basins, there’s a linear relationship between naturalized flows and observed flows. This relationship allows for the consideration of extended naturalized flow regimes for planning purposes until the state formally updates the flows.

Citation

Zhu, J., Fernando, N., and Guthrie, C., 2020, Extension of naturalized flow using linear regression: World Environmental and Water Resources Congress 2020, p. 162-173. https://ascelibrary.org/doi/10.1061/9780784482957.017

 

Author

Robert Mace

Robert Mace

Executive Director & Chief Water Policy Officer at The Meadows Center for Water and the Environment

Robert Mace is the Executive Director and the Chief Water Policy Officer at The Meadows Center. He is also Professor of Practice in the Department of Geography at Texas State University. Robert has over 30 years of experience in hydrology, hydrogeology, stakeholder processes and water policy, mostly in Texas.

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