Flooding & Floodplains
Harris County's Flooding History
Flooded from the Beginning
When the Allen brothers founded Houston in 1836, they established the town at the confluence of Buffalo and White Oak Bayous. Shortly thereafter, every structure in the new settlement flooded. Early settlers documented that after heavy rains, their wagon trips west through the prairie involved days of walking through knee-deep water.
They Drained The Land
The new settlers didn't like this natural flooding because it wasn't conducive to building towns or farming the land. So, they set out to "drain" the land, and to clear it of much of its natural habitat for agriculture or timber for construction.
However, there is a big difference between drainage and flooding. The settlers wanted to "drain" the land, which meant they wanted to make the water go away. They did it without any purpose, other than to make the water go away in a reasonable time and to make the channels flow downhill. As the channels got deeper, they also got wider. The early residents didn't plan with any particular rainfall amount in mind.
The Rains Kept Coming
Harris County suffered through 16 major floods from 1836 to 1936, some of which crested at more than 40 feet, turning downtown Houston streets into raging rivers. After the tremendously destructive floods of 1929 and 1935, however, citizens clamored for solutions. Estimated property damage in 1929 was $1.4 million, a staggering sum at the time. Losses more than doubled in 1935, when seven people were killed and the Port of Houston was crippled for months - its docks submerged, its channel clogged with tons of mud and wreckage, its railroad tracks uprooted. Twenty-five blocks of the downtown business district were inundated, as well as 100 residential blocks. If ever there was a county in need of flood assistance, this was it.
Action Was Needed
Politically, the timing couldn't have been better. All across America during the 1920s and '30s, the federal government was financing huge water infrastructure projects, damming great rivers at a pace no previous civilization could have imagined - converting deserts to fertile farmland with irrigation in the West, submerging farmland in the East to create reservoirs for power. Major projects were funded through the U.S. Army Corps of Engineers, which for years employed the nation's only civil engineering experts. Houston's commercial future hinged on its ability to tap into this federal machine, but it needed a local agency to serve as a sponsor.
Action Was Taken
On April 23,1937, after local leaders submitted a petition with dramatic photographs of past flood devastation, the 45th Texas Legislature unanimously passed the bill which created the Harris County Flood Control District.
Nature Always Prevails
Since the District's creation, and despite a history of successful flood damage reduction projects and progress throughout Harris County, close to 30 damaging floods have occurred in the area, resulting in hundreds of millions of dollars in damages in just under 70 years. However, after the 1940's, the Harris County area did not suffer what would be considered a widespread, regional flood, that is, until June 2001.
Allison: A Name We'll Never Forget
Tropical Storm Allison suddenly formed 80 miles off the coast of Galveston, Texas, on Tuesday, June 5, 2001, no one expected that, five days later, it would go on record as one of the most devastating rain events in the history of the United States. Neither historical data nor weather forecasts could adequately predict this extraordinary storm that, before leaving the area, would dump as much as 80 percent of the area's average annual rainfall over much of Harris County, simultaneously affecting more than 2 million people. When the rains finally eased, Allison had left Harris County, Texas, with 22 fatalities, 95,000 damaged automobiles and trucks, 73,000 damaged residences, 30,000 stranded residents in shelters, and over $5 billion in property damage in its wake. Leaving 31 counties with declared disasters in Texas, Allison went on to spread disaster declarations to Louisiana (25 parishes), Florida (nine counties), Mississippi (5 counties) and Pennsylvania (2 counties). Allison was the costliest tropical storm in the history of the United States.
Flooding is OUR Natural Disaster
Harris County doesn't have earthquakes... doesn't have blizzards... doesn't have avalanches. We have flooding. A major flood still occurs somewhere in Harris County about every two years. Most of the flooding is in areas developed prior to the current understanding of flood potential and prior to regulations restricting construction in flood-prone areas. Fortunately, since the 1970's, there has been flood insurance to ease the financial impact of flooding. Despite tremendous flood damage reduction projects that have indeed reduced the risk of flooding, more flood insurance funds have been paid here than in any other National Flood Insurance Program-participating community.