The National Weather Service issued a rainfall study that aims to help state and local officials better understand potential flood risk in their areas. The study, known as Atlas 14, shows that the frequency of major storms that can take place in Fort Bend County and Sugar Land is expected to increase.
The Atlas 14 rainfall values are used for infrastructure design and planning activities under federal, state, and local regulations. They also help to determine flood risk, manage development in the floodplains, and forecast flooding threats for the entire state of Texas.
Sugar Land adopted the Atlas 14 rainfall frequency estimates for Texas on April 2, 2019. This resulted in modifications to the city’s Development Code and Design Standards, the city-adopted guidelines that provide guidance for the review of requests to alter or develop new property within the city.
These changes resulting from the Atlas 14 adoption applies to new development and redevelopment areas within the city and its extraterritorial jurisdiction (ETJ).
The city updated city-wide ponding maps using the new Atlas 14 rainfall information in the fall of 2020. The updated maps shows the areas where potential street ponding might occur due to an increase in the frequency of intense rain events.
Before the study, Sugar Land had a 1 percent chance to receive 12.5 inches of rain to fall in 24 hours (1 in 100) at any given time. The Atlas 14 study shows that this amount of rainfall is now likely to occur more frequently - a 4 percent chance for 12.5 inches of rain to fall in 24 hours (1 in 25) at any given time.
Areas located inside the current FEMA floodplain boundaries and areas protected by levees might see an increased risk of street ponding due to the Atlas 14 rainfall values.
Jorge L. Alba, P.E., CFM
Senior Engineering Manager
2700 Town Center Blvd. N.
Sugar Land, TX 77479
Ph: 281-275-2780 | Fx: 281-275-2771