The San Antonio Flood of 1921 Held Lessons We Refuse to Learn

We forget what we don t want to remember While I understand that impulse there are dangers embedded in our forgetfulness This is especially true for anyone living in Flash Flood Alley or what we like to call the Hill Country a concept that softens the nature of this flood-sculpted and -scoured terrain So I have come to believe after nearly thirty years of thinking researching and writing about the September flood which ravaged Central and South Texas it killed at least people and in its devastated epicenter San Antonio or more perished Yet those who survived that flood were surprised to learn that the Alamo City endured an even larger-in-size though less fatal inundation in There was little to no constituents memory People did not die solely because of forgetfulness but because this amnesia allowed succeeding generations to erase the past and their responsibilities to the future When they could have enacted post-flood life-saving interventions they chose not to act on their progeny s behalf Here s hoping that does not hold true for the majority modern accident the swift and punishing rise of the Guadalupe River over the July Fourth weekend It swept away well more than children and adults a horrific tally which may never be known in full As with the flood when general officers admitted that a few bodies might not be recovered interred as they were beneath tons of silt gravel rock and other debris so too with the Guadalupe We don t know where they are Kerr County Judge Rob Kelly acknowledged We don t know how numerous we ve lost That uncertainty intensifies the anguish even as it testifies to this flood s catastrophic impact Mercifully the official missing persons count was reduced over the past weekend from around to three largely due to individuals being ratified safe But there is nothing unknown about what triggered the brutal flood and so various others dating back to the nineteenth century when the first if spotty records were kept Particular of the explanation results from where the Guadalupe like the Colorado and San Gabriel rivers to its north and the San Antonio to its south originate Their tributaries rise in the rugged Edwards Plateau the massive landform whose -million acres dominate and define Central Texas Although the plateau s elevation is modest with its eastern sectors varying from to feet above sea level this range in height is less vital than its relation to the very gulf waters against which the plateau is measured Put a pin next to the source of your local or favorite watershed then follow it as it streams south and east on its run to the Gulf of Mexico Find the nearest beach put your feet in the water If it feels like a hot tub you are in the right place In mid-July for instance water temperatures at Port Aransas measured between - F This heat index becomes the second datapoint essential to understanding the thunderous storms that have blown up over the Edwards for millennia The third is the prevailing breezes that capture the steamy moisture rising off the gulf and in counter-flow to the rivers sweep north and west slowly rising with the coastal plain It is a relatively gentle climb San Antonio sits feet above sea level New Braunfels at and Austin at But almost promptly to the northwest gentle turns steep That s because this wet air hits the Balcones Escarpment a geological structure of faults that curves northeast from Del Rio to Waco It marks a sharp increase in elevation Though they have the Guadalupe River in common Kerrville is feet higher than New Braunfels And what a difference the upcountry makes As that moisture-packed airflow swirls aloft it hits cooler temperatures and begins to condense and fall then reheat and rise again a cycle of convection that as it repeats can generate thunderheads Should this volatile mixture collide with a cold front the whole might explode That s how C Terrell Bartlett a San Antonio-based engineer explained the flood to the annual conference of the American Society of Civil Engineers one month after it tore through South and Central Texas It has long been recognized that in a large number of cases the sudden rise at the Balcones Escarpment causes intense precipitation along and just above its margin What they knew then we must recall now United States Army soldiers assisting with search-and-rescue operations using a pontoon boat on Saint Mary s Street by the Gunter Hotel following the flood Coates Library Digital Collections Trinity University San Antonio We also need to recollect that the atmospheric-disturbing escarpment is key to why the Hill Country is so flood-prone Every storm whatever its size and power has dumped rain that over thousands of years has carved channels into the limestone bedrock to sluice water downhill an erosive force that has created a few of the very aesthetic features braided riverbeds steep-walled canyons and breathtaking views that have drawn so various to this rough terrain Farther downstream the alluvial actions of these riparian systems even at normal flow have carried critical nutrients downstream At flood-stage these biotic riches have been dispersed across and built up floodplains reenergized wetlands and nurtured habitats Rivers sustaining pulse their dynamic and regenerative influences are key to James Scott s brilliant and posthumously published In Praise of Floods Its opening sentence Rivers on a long view are alive testifies that they are as well the life-source for all species The Indigenous people of what is now Texas understood this concept full well They knew that the dangers we associate with Flash Flood Alley were indistinguishable from the manifold benefits floodwaters bore They were just smarter about how to live within a river s embrace siting their communities near springs and adjacent to fertile floodplains but invariably above historic high-water levels Missing that long-lived insight were Spanish and later Mexican and American colonists whether Canary Islanders German migr s or white enslavers These settlers depended on sedentary agriculture that led them to plow and dig their communities into the flood zones of the San Antonio Guadalupe and Colorado rivers Controlling floods not shifting the pattern of settlement to safer ground became the ambition every time San Antonio was inundated Beginning in the s local engineers and a handful of inhabitants functionaries urged the construction of a flood-retention dam to bottle up the city s eponymous river north of the downtown core It would take seventy years and countless deadly floods for that structure to gain taxpayer approval in it would take until the s and a lot of grassroots protests on the city s vulnerable West Side a sector that the flood destroyed to gain protective infrastructure Austin was faster off the mark In after years of enduring a rain-swollen Colorado jumping its banks and ravaging the group the city using its municipal tax and bond powers built a sixty-foot high -foot-long granite-block dam The structure took advantage of the river s historic path The Colorado above Austin follows in a deep cut or canyon worn in the limestone rock wrote UT-Austin geologist Thomas U Taylor It is skirted by limestone bluffs rising often to the height of feet above the bed of the river broken by the erosion of tributary streams No extensive meadow or bottom lands exist This situation permits the construction of a high dam with but little damage to private property Under ordinary circumstances the Colorado occupied only a small part of the channel but in great floods the river spreads from bluff to bluff In after a series of massive storms the Colorado slammed into the structure overtopping and undercutting it killing dozens Its spectacular failure Taylor asserted was due to ignorance of the site s geology poor engineering and political interference and one other factor silt The river carried so much grit downstream that it acted as a gigantic sandblaster and the structure broke before the churning onslaught Advertisement William L Bray one of Taylor s university colleagues wondered whether there was a human component to the speed and debris-packed floodwaters A botanist Bray received a contract from the U S Bureau of Forestry to document on the Timber of the Edwards Plateau of Texas Before you yawn note that the statement s subtitle offered a more ecological analysis of woody vegetation s Relations to Atmosphere Water Supply and Soil With that encompassing objective Bray roamed the Balcones Escarpment and the wider plateau and paid close attention to how people were using axe and animals to eke out their living in the thin-soiled landscape Cedar choppers were hard at work harvesting for fencing and fuel sheep goat and cattle were grazing on what grasses were available These economic initiatives came with considerable environmental costs Bray argued after studying two canyons linked to the Colorado River One of them retained its thicket of vegetation the other had been stripped clean Unlike the first which acted like a sponge during rain events the denuded slopes of the other did little to restrain precipitation from racing downhill to pour down as from a steep roof converging into swift streamlets which erode every vestige of organic soil This load along with other heavier debris then crashed into already roiling tributaries the whole becoming a mountain torrent The Colorado floodwaters with their anthropogenic and natural sources continued to run free until the completion of Austin s Tom Miller Dam Its funding not incidentally came from the New Deal s Population Works Administration a million gift that the Hill Country s native son then-Representative Lyndon B Johnson had secured To date that initial expenditure and subsequent infrastructure projects that the Lower Colorado River Authority manages have protected communities within the larger watershed under majority of conditions But what just happened on the Guadalupe and had occurred on the San Antonio in was not majority conditions Let s return then to the Gulf of Mexico and its simmering saltwater Add to its hot-to-the-touch condition an atmosphere containing elevated levels of humidity and crucially the absence of strong shearing winds Overhead powerful thunderstorms might begin to form As they do they suck up more warm moisture into a spiraling system The pressure begins to drop which pulls in more wind and if these conditions hold a tropical depression might morph into a tropical storm or hurricane Latest research connects the dots between this formative process and ocean surface temperatures warmer waters NOAA notes fuel more energetic storms The surface and lower depths of the Gulf were not nearly as hot a century ago as they are this day a difference attributable to climate-disrupting planetary warming context change is an accelerant boosting and intensifying a pre-existing weather pattern One of those earlier storms a strong tropical depression that formed in the gulf in early September slowly spun towards northern Mexico and on September th it came ashore south of Tampico Over the next three days it cycled across the Rio Grande into Webb County then drifted along the Balcones Escarpment to rain down over Bexar Comal Hays and Travis counties before pounding Williamson Bell and Milam The U S Weather Bureau could not formally verify the distribution of the pressure that directed the storm s path yet it insisted that the shifting winds the progressive northeastward extension of the rainfall area and the profound agitation of the atmosphere as evidenced by violent squalls and thunderstorms over the stricken section can hardly be ascribed to any other cause San Pedro Creek near Commerce Street following the flood Coates Library Digital Collections Trinity University San Antonio Contemporaries recorded two crucial results of the deluge Because San Antonio was the largest part densely populated and the majority highly developed district affected by the flood it received the largest part widespread notice in the press Yet its attention-grabbing devastation needed context C E Ellsworth a USGS researcher averred If the rainfall in the basin of San Antonio River had been as heavy as it was in much of the basin of Little River in Bell Milam and Williamson counties the destruction at San Antonio would have been so great as to make that veritably suffered there seem insignificant That s why the aggregate loss of both life and property in other areas far exceeded that at San Antonio though who died in the various flood zones was consistent Majority were Mexicans who lived in poorly constructed houses built along the low banks of the streams Undoubtedly a multitude of others were drowned who were never shared missing Ellsworth wrote and along the Little and San Gabriel rivers bodies were revealed six months or more after the flood Particular of this analysis is hauntingly familiar The pile-driving origin of the inundation in Kerr County was yet another tropical disturbance dubbed Barry that made landfall in northern Mexico and headed across the demarcation where later it slammed into already saturated skies whirling above the Edwards Plateau As with the storm during which record-setting whiteout downpours hit the upper reaches of the San Antonio River and the middle stretches of the San Gabriel inches fell at Thrall specific parts of the Guadalupe watershed had more than inches hammer down so fast that the river itself rose feet within less than an hour That s a predictable end of the tight confines through which escarpment rivers squeeze As foreseeable alas is the calamity that results if this torrent powers into urban streets or a rural camp called Mystic Neither flood could have been prevented It is a river s nature to flood But the human-made disasters that resulted could have been mitigated The Dallas Morning News spoke to this in a September editorial Flood Yet to Come observing that the the majority distressing feature of San Antonio s disastrous flood experiences is the probability that they were avoidable It does not seem unreasonable that foresight could have prevented the great loss of life and property and proof that it was preventable will come in the decision to take strategies at once to prevent the recurrence of the catastrophe Solutions could have been proactively implemented The state was duly forewarned Scarcely is there a city of any size in Texas the News continued but has within its confines one or more placid water subject potentially as murderous as the beautiful San Antonio River The post The San Antonio Flood of Held Lessons We Refuse to Learn appeared first on The Texas Observer