Texas has approximately 7,500 non-federally owned dams; nearly 1,000 are classified “high-hazard,” approximately 750 are “significant hazard,” and the balance is deemed “low hazard.” Back in 2009, the State enacted legislation requiring owners of “high” and “significant hazard” dams to file an Emergency Action Plan (EAP) with Texas Commission on Environmental Quality (TCEQ). This requirement was mandated by January 1, 2011.
At its simplest, an EAP is a plan of action for the owner, the State, neighbor community (if any), municipal of the dam or levee location, and other jurisdictional entities to follow if the dam or levee should fail or be in imminent failure. It’s value is obvious but, like car or home insurance, hopefully never needed. The reality is, especially in the case of “high hazard” dams, it very well may be needed to save lives.
Development of the EAP involves hydrologic modeling, hydraulic modeling, dam break analysis, inundation mapping, property identification, and emergency contact chart. TCEQ regulations allow for the use of the “Simplified Dam Breach” method for small and intermediate sized dams which have limited downstream development (constituting the majority of Texas dams). Hydraulic model preparation and inundation mapping are expedited through the use of GIS specialty software.