People tend to forget we live in a swamp. Houston wasn't considered very habitable until the invention of air conditioning. We used to lead the nation in cases of yellow fever and cholera, and we had frequent cases of malaria well into the 50's. The large number of bayous has been a constant source of flooding, the Flood Control District starting converting the bayous in the 1950's from muddy rivers to the managed culverts you see today. While this doesn't prevent flooding, it does help control the damage. Houston tends to forget we owe the creation of the Flood Control District to an engineering bungle in 1935 that helped destroy downtown.
The Houston Ice and Brewing Company was founded in 1893 by Hugh Hamilton. It quickly became the largest brewery in Houston, encompassing 40 acres in downtown. The brewery changed its name to the Magnolia Brewery and was recognized as one of the best breweries in the nation. To help transport its products the Magnolia Bridge was constructed in 1912. At the time the bridge was considered a masterpiece, Mayor Rice called it a beauty spot of downtown, its narrow base hiding the ugly mud banks of Buffalo Bayou. The Magnolia Brewery survived Prohibition just selling ice, and weathered the Great Depression selling beer again. In 1935 however, the 'beauty spot' of a bridge came back to haunt the entire city.
Texas was having unseasonably wet weather that particular year. Austin and the Hill Country had been hit hard by heavy rains, and much of North Texas was equally soaked. Since Houston was the final destination for the runoff, our bayous reached maximum capacity fairly quickly in December. On December 7th , Houston was hit by heavy rains. The rain only amounted to 5” in the downtown area, but higher rain falls in the north of the city added even more water. In this situation the bayous would have overflowed their banks evenly like they had in the past, the problem this time was the Magnolia Bridge.
The bridge's base, once lauded for its narrow base obstructing the view of Buffalo Bayou, was too narrow for the water to pass through easily. The water backed up until Buffalo Bayou became a reservoir. The water passing under the bridge was under pressure from the water behind it and caused the flood to move at a fairly alarming rate. The water reached 8' deep on Milam Street, and because of the fast moving waters the damage to the building was significantly higher than it would have been in just stagnant water. Bits of buildings were washed away, and several buildings were taken completely off their foundations.
Houston was not prepared for such a large amount of water in the center of the city. The flood reached the Heights before subsiding. The emergency responders were pushed beyond measure. The Fire Department was at a severe disadvantage as the floods had knocked out every pumping station in the area. When Yellow Cab caught fire, the Fire Department was forced to sacrifice trucks by driving into the flood waters and pumping the water straight from the flood to extinguish the fire.
The flood officially lasted until December 10th. When the waters receded the damage was historic. Almost every bridge in downtown was out. Every building had suffered serious structural damage, and somewhere between 20-40% of the buildings were a total loss. The Magnolia Brewery was destroyed in the flood, as well as the city post office, the MK&T railroad, the Farmer's Market and the city archives. The damage was in the millions of dollars at the height of the Great Depression.
The State of Texas ordered an investigation in 1937 on the cause of the increased magnitude of the flood. The commission came down hard on Hamilton's bridge, labeling it as the sole cause of the disaster. For decades after the Magnolia Bridge was synonymous with incompetence in Houston. The city and the state took measures to prevent anything like the flood from ever happening again, leading to the creation of the Flood Control District. Any result was the construction of the reservoirs to hold excess run off during heavy rainfall. Devastated by the flood and the fall out, the Magnolia Brewery limped along until 1950 until it shuttered its doors. You can still find the remnants of the old bridge under the Louisiana Bridge, and portions of the old Brewery itself are still around as the Magnolia Ballroom and Brewery Tap.