Stormwater Control System
The City's stormwater system is intended to direct the flow of stormwater runoff to minimize the potential adverse impact of rising water from rainfall events.
Stormwater control systems should not be considered means to absolutely prevent flood damage. Rather, they should be considered the engineered best management practices to reduce the potential for flood damage.
The City's stormwater control system has evolved over a number of years and has repeatedly demonstrated its effectiveness in reducing the potential for flood damage. This has been evidenced by limited flood damage during extreme rainfall events - much more limited than the FEMA floodplain maps indicate could potentially have been damaged by flooding during these excessive rainfall events.
Operation and maintenance of the City's stormwater system is intended to assure that the system operates as effectively as possible in controlling stormwater runoff.
Floodplain Management & FEMA
The Federal Emergency Management System (FEMA) administers the National Flood Insurance Program (NFIP) which has evolved as the benchmark program to assist all communities in reducing damages due to flooding. Stormwater control systems are interrelated with the NFIP in that they can be of benefit in complying with floodplain management best management practices, but stormwater control systems by themselves do not change the FIRMs on which potential flood damage insurance rates are based.
The program has three major components:
Controlling Water Quality
- FEMA Flood Insurance Rate Maps (FIRMs) - These maps are legal documents defining areas susceptible to flooding. These maps have been derived from extensive, advanced engineering analysis and provide the basis for which all flood management activities must adhere.
- The comprehensive program for floodplain management is a detailed set of guidelines of best management practices for use in planning land use to reduce the potential for flood damage. The City’s floodplain manager administers this program for the City of Nassau Bay.
- A federally managed insurance program which protects owners who experience flood damage. If the first two components above are accepted by municipalities, then the community’s residents are provided with the opportunity to obtain reduced-rate flood insurance from the NFIP.
The stormwater system also has significant impact on our environment by helping control contaminants trying to enter our local waterways. Stormwater runoff is directed through the stormwater system to local waterways. Thus, any contaminant introduced into the stormwater system flows directly into those waterways.
The City of Nassau Bay has a Municipal Small Separate Storm Water System (MS4) permit, which is issued by the Texas Commission on Environmental Quality (TCEQ). This permit requires that the City manage its stormwater system to prevent contaminants and harmful wastes from entering the stormwater system and thus entering Clear Creek, Clear Lake, and Galveston Bay. All of these are endangered waterways which have elevated levels of harmful contaminants. Nassau Bay is doing its part to eliminate the sources of these harmful contaminants.
Residents have a particularly important role in assuring that the stormwater control system operates properly by making sure that yard debris, construction debris, and other obstructions or hazardous materials are not placed in storm drains.