BROWNSVILLE, Texas — The Rio Grande River began about 26 million years ago to the Sangre de Cristo Mountains up in northern Colorado. Around 3,000 years ago, a delta formed. As the delta built up, there was a resistance because there was a landmass and you had water trying to push uphill to a certain degree. That is where you had the formation of the resacas.
Around those 3,000 thousand years ago, there were cutoffs of the main path of the river. The first one was identified as being Los Cuates Resaca in the area of Los Fresnos. After that you had the various distributaries that formed because the main path of the river was here and then the other ones had to fan out on this delta.
These other resacas are in Rancho Viejo. You have Resaca de La Palma and then the city resaca in the center of Brownsville. The cities of the Rio Grande Valley when they were first colonized in 1848, the resacas did not look anything near what they look like now. The resacas that we are familiar with were swales, they were dips in the topography from ancient travel paths of the river.
After the coming of the railroad that is when this area started to really settle. It was John Closner, at least he is given the credit for utilizing the resacas as reservoirs. The city of San Benito and the city of Brownsville took steps in order to dredge those swales into receptors of waters that would be utilized as reservoirs for the irrigation of crops and for human use.
People who are new to this area say what is a resaca? The original Spanish word is “sacar” which means to cut off. It is a cut off from the main river. It is an isolated path after the flood waters recede there are all kinds of meanderings and pools of water. That is what is called a cutoff and that is what a resaca is. Once they were formed, the reservoirs were made, the river was tamed, then we started coming into the phrase “Rio Grande Valley.” Why is it a valley? The steep walls you would normally see in a valley are not there.
Think of it in other terms that are present in U.S. geography. The Mississippi River Valley, the Tennessee River Valley, the Ohio River Valley. They are not valleys like this. They are drainage areas. They are water sheds. That is what we mean by valley. Then we come into the phrase Magic Valley. That was a marketing phrase that came about after the railroad came in 1904. The land settlers that came in, the opportunists that came in order to take care of building the agriculture base said we got to put some pizzazz on that, so they called it the Magic Valley. It was an effort to draw some allure to this part of the country.
All that this river gave in terms of the lifeline, the water source, life giving water was so important to the development of what we call today the Rio Grande Valley.