RESACAS: CROWN JEWELS OF THE VALLEY By W.F. Strong Resacas make the Rio Grande Valley a magical land. They create habitats for migrating birds that light up the landscape with their bright colors. Resacas provide serene habitats for people, too. Many fine homes enjoy the tranquil backyard ambiance these waterways provide. Fish, turtles, huge alligator gars, nutria, along with an occasional alligator, are abundant in these Rio Grande River distributaries created eons ago. In other parts of the world, similar twisted basins are often called oxbow lakes, places where the river changed course and left a dry or seasonal pond, or boggy pools behind. Australians call them billabongs. Yet our resacas are much more than oxbow lakes. Dr. Jude Benavides, Rice educated PhD in environmental science and professor of environmental sciences at UTRGV, is quick to clarify that oxbow lakes are features of resacas, but resacas themselves are far more grand. “They are”, he says, “more than anything else, ancient distributaries of the Rio Grande River.” The region was, in fact, for thousands of years, a smaller version of the Nile River delta, with the river overflowing its banks quite often. The flood waters carved out channels in the softened earth as they pushed toward the sea. Those channels, created at different times, remain with us to this day. I believe that had you come upon this river delta a thousand years ago and been able to get a time-lapsed Google Earth view over a few centuries, it would have looked perhaps like the illustration below.
A quick look at the most popular use of “resaca” in the Spanish speaking world gives us clarity on its geographical meaning. Mostly, the word is used like this: “Tengo resaca,” which means I have a hangover (though here in the Valley “cruda” is more common). That’s what a resaca lake or channel is, a hangover from overflow or flooding or a change in the river’s course. It comes from the verb, resacar, which is to take out and put back, again and again. That’s why resaca also means undertow as in resaca del mar. Ebb and flow. Flooding of the river over thousands of years created channels that sought to distribute, as efficiently as possible, excess water toward the sea. When the flooding ceased, the channels dried up, but then filled again when the flooding returned the next rainy season. In modern times, municipalities and irrigation districts pump river water into the resacas to use them for storage and to push the water out to distant farms, where it is vital for producing bountiful harvests of citrus, sugar cane, and row crops, including vegetable and grains, and fabric crops like cotton and hemp. Thanks to resacas, the Valley truly is the Magic Valley.
These are the five resaca systems that are maintained in the LRGV. Courtesy of Dr. Jude Benavides.
Illustration provided by Dr. Jude Benavides. He stresses that the depiction is for the clarity of the channels and should not imply that the resacas were all created, or full and flowing, at the same time. 20B
MVEC Pages January 2022_.indd 6
JAN UARY 2022
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