The San Jacinto River Regional Watershed Master Drainage Plan (SJMDP) was a comprehensive regional study led by local study partners including the Harris County Flood Control District, Montgomery County, the City of Houston, and the San Jacinto River Authority. The study identified and developed information for communities to use for hazard mitigation planning along the channels included in this study. As extreme weather events and flood waters do not recognize jurisdictional boundaries, like county and city limits, the four study partners worked together to address flooding as a regional issue.
This comprehensive study developed a set of hydrologic and hydraulic models for the major streams of the Upper San Jacinto River regional watershed that will provide a technical basis for local, state, and federal agencies to identify flooding vulnerabilities for existing infrastructure and impacts from future growth to improve flood resiliency in the watershed. The models developed for this study used the new Atlas 14 rainfall data, the most current terrain data, and the latest technology to develop a comprehensive model that represents the various streams and their interaction with the San Jacinto River watershed.
Potential projects supported by the results of this study are intended to reduce flood risks to people and property located throughout the watershed resulting in better informed and more resilient communities. Information developed includes non-regulatory inundation maps (not intended to replace current FEMA effective Flood Insurance Rate Maps) for the studied streams that show the extent and depth of riverine flooding of the major streams within the watershed for an array of simulated storm events. Additionally, information was gathered about the number of structures, acres of land, , and miles of roadway as well as critical infrastructure and evacuation routes, that are located within the inundated areas.