The Flood Control District does "not" have sole jurisdiction over flood-related matters in Harris County. In fact, there are many other entities involved that have special interests in their particular areas of responsibility.
The City of Houston, for example, is one of the local floodplain administrators for the community's participation in the National Flood Insurance Program (NFIP). The city has its own criteria for design of its drainage systems - primarily the design of storm sewers and street drainage, but also stormwater detention for these systems. Other incorporated areas are also floodplain administrators and have their own drainage design criteria for their road systems. In unincorporated areas of Harris County, the County Engineer's office is the floodplain administrator.
In all, there are 34 floodplain administrators in the county. The Flood Control District is not one of them. To complete the jurisdiction picture, there are four county commissioners' precincts. In all, with 34 floodplain administrators reporting to separate entities of government, there are nearly 250 elected officials involved in the administration of drainage and flooding issues in the county, including each municipality's building permit program.