Climate and Aridity in the Texas Borderlands

Climate is a deciding factor in human habitation and migration patterns. Mapping Texas aridity, vegetation, and groundwater helps us better understand striking economic and social differences between the dry western half of the state and the wetter eastern sections. As demonstrated in the map below, the Permian Basin’s vast oil deposits are located in some of the driest, hottest, and most inhospitable portions of the state. This has shaped the oil industry in West Texas, as well as influenced the region’s political and economic development.



As the above map demonstrates, in western Texas, average precipitation ranges between only 10 to 20 inches of rain per year. This lack of rain has made farming a risky proposition in the region.

During the 1880s the Texas Legislature was very interested in settling western Texas quickly, selling off most of the region to railroad companies. The map below uses data from the original Texas Land Survey, ongoing between the 1860s and the early twentieth century, to demonstrate the extent of this land-grab. Reds, purples, and pinks, all represent holding by railroad companies. Left white, is land owned by individual or family farmers. Green represents land owned by the State of Texas.


This map illustrates a few historic trends: It is interesting to note that federally owned land is almost nonexistent in Texas. Further, this map demonstrates the divide between the wetter and more fertile eastern half of the state and the dryer, sparsely inhabited west. The eastern half of the state was divided into small farms, many worked by sharecroppers. The west was dominated by first railroads and then a network of vast ranches.

Hoping to profit from their landholdings, railroad companies established towns along the rail lines, hoping to attract settlers. By the early-twentieth century, this network was extensive. Below is a map tracing railroad lines, recorded towns and the region’s different climate zones.


The number of towns listed in the above map is deceptive. Many held less than ten people, others none at all. Data for this map comes from historic railroad freight maps which were used to promote commerce along the rail lines. The map creators had a vested interest in demonstrating a settled region with a growing population. In reality, most of these towns disappeared after 1920. Once again, climate was the culprit.

The graph below, created by the National Oceanic and Atmospheric Association, tracks patterns of drought in Texas. The late 1920s were years marked by deep drought.



During this period many people left West Texas, heading to greener regions that were easier to farm. Savvy ranchers bought much of the arable land from desperate homesteaders looking to leave the region. The map below demonstrates that despite the best efforts of railroad boosters, in 1920 to population of West Texas was still strikingly less than the rest of the state.








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