Which waterways drain Fort Bend County?
The Brazos River flows diagonally northwest to southeast through Fort Bend County and drains its central valley, according to the Handbook of Texas. The San Bernard River forms the west boundary and drains the western quarter. Big Creek flows east into the Brazos. Oyster Creek winds parallel to and east of the Brazos. Buffalo Bayou rises in the northern tip of the county and flows east into Harris County.
Upper Oyster Creek runs about 54 miles, according to the Houston-Galveston Area Council. It begins at the Gulf Coast Water Authority Shannon Pump Station on the Brazos. Its watershed covers about 110 square miles and includes Fulshear, Sugar Land, Stafford and Missouri City.
Who maintains drainage?
The Fort Bend County Drainage District maintains drainage channels where it holds easements. It reviews drainage plans and plats for new developments. Its interim Atlas 14 drainage criteria manual took effect January 1, 2020, and was updated in September 2021.
What are levee improvement districts?
Levee improvement districts (LIDs) are political subdivisions of the state. They build and maintain levees and drainage, according to the City of Sugar Land. The Texas Commission on Environmental Quality supervises them. They repay tax-exempt bonds with property taxes. Directors are appointed by Commissioners Court or elected by residents.
Nine LIDs operate over most of Sugar Land: First Colony LID, First Colony LID 2, and Fort Bend County LIDs 2, 7, 10, 11, 14, 15 and 17. Where no LID operates, the city handles stormwater and floodplain functions. Riverstone sections fall in LID 15 or LID 19. At Sienna, the developer built a ten-mile levee across about 6,000 wooded acres in the mid-1980s, according to the Handbook of Texas.
Which flood maps apply?
The Drainage District lists the county floodplain map as effective April 2, 2014. It followed a five-year mapping project by FEMA and the county. FEMA has since released revised preliminary maps for Fulshear, Simonton, Weston Lakes and unincorporated Fort Bend County.
When is a county floodplain permit needed?
The Fort Bend County Engineering Department issues development permits for all unincorporated areas, and for Kendleton, Thompsons, Fairchilds and Pleak under interlocal agreements. A permit is required for any work in a floodplain or flood-prone area shown on the latest Flood Insurance Rate Maps. Fill or excavation over 500 cubic yards per acre, or an elevation change of six inches or more, also needs a permit.
What major floods has the county seen?
The Handbook of Texas records a major Brazos River flood in June 1899. The National Weather Service gauge on the Brazos at Richmond lists these top crests. Flood stage there is 45 feet and major flooding begins at 50 feet.
| Date | Crest (feet) |
|---|---|
| Sept. 1, 2017 (Harvey) | 55.19 |
| June 2, 2016 | 54.74 |
| Nov. 28, 1940 | 51.40 |
| Oct. 21, 1994 | 50.30 |
| May 5, 1957 | 50.13 |
On August 27, 2017, the county made its Brazos River evacuation order mandatory. More events are in Major flood events in Greater Houston.
How do I check a Fort Bend address?
- Look up the address on the FEMA Flood Map Service Center at msc.fema.gov, the official source for flood maps.
- Open the county Floodplain Mapping Tool, linked from the Drainage District’s Flood Insurance Study page.
- Check the Drainage District’s levee district map to see whether the address lies in a LID.
- Follow river levels on the district’s gauge page, which links 12 gauges in the county and 13 upstream.
For Houston addresses, see How do I find out if a Houston property is in a floodplain?