- Engineering & Capital Projects
- Floodplain & Stormwater
- Floodplain (FEMA) Maps & Flood Information
Floodplain (FEMA) Maps & Flood Information
Preliminary Flood Maps in Williamson County, TX Ready for Public View
Homeowners, renters and business owners in Williamson County are encouraged to look over newly released preliminary flood maps in order to determine their flood risks and make informed decisions.
County officials and the Federal Emergency Management Agency (FEMA) are presenting the preliminary maps to communities and unincorporated areas in Williamson County in order to help leaders and residents identify known flood risks and use that information to make decisions about buying flood insurance and any future development.
View the Interactive Map with General Overview of Changes.
Release of New Floodplain Maps
The Department of Homeland Security's Federal Emergency Management Agency (FEMA) is in the process of releasing new floodplain maps for the portion of the City of Cedar Park that lies within Williamson County. FEMA identifies floodplains in order to calculate flood risks for insurance purposes, particularly within Special Flood Hazard Areas (SFHA). SFHAs are defined as the area that will be inundated by the flood event having a 1% chance of being equaled or exceeded in any given year. The 1% annual chance flood is also referred to as the base flood or 100-year flood.
The new maps are a result of a multi-year study of the Upper Brushy Creek watershed prepared by the Texas Water Development Board (TWDB) and the Upper Brushy Creek Water Control and Improvement District (UBCWCID). The City of Cedar Park was an active member of the Technical Advisory Committee for the UBCWCID watershed study. The new floodplain maps are the result of new technology and data which yields a better assessment of where flooding is most likely to occur close to creeks and more accurately predict floodplain boundaries. In most cases, mapped drainage boundaries have not changed.
Floodplain Comparison Mapping Tool
Williamson County has prepared a Simple Mapping Tool that compares the current effective floodplain limits to the proposed new floodplain limits. Simply click the blue "I want to…" button to see a list of options. Use the "Address Search" to enter an address and zoom the map into the appropriate area.
Alternatively, the following link is provided by FEMA to access the same information, however, the Williamson County webpage linked previously is more user friendly:
- On January 30, 2017, FEMA posted digital copies of preliminary Flood Insurance Rate Maps (FIRM), Flood Insurance Study (FIS) report materials, and supporting data on their Map Service Center website
- Why are floodplain maps being updated?
The maps are being updated because the majority of the maps are based on analyses that were performed over 25 years ago. Watershed conditions such as topography have changed and there has been significant added development. Furthermore, analysis tools and historical data collection have improved over time and will increase map accuracy.
Flood hazard mapping is an important part of the National Flood Insurance Program (NFIP), as it is the basis of NFIP regulations and flood insurance requirements. The Federal Emergency Management Agency (FEMA) maintains and updates data through Flood Insurance Rate Maps (FIRMs) and risk assessments.
- How often are these maps updated?
There is no set timeline. Flood zone designations may be revised when new and more accurate information becomes available because of a FEMA-funded restudy or because the community makes the information available to FEMA. Several factors influence the frequency with which flood maps may be updated, such as the extent of new development and the completion of flood-control projects.
There are no comprehensive updates foreseen in next 10 years.
- Who initiated the update?
FEMA initiated a partial update in 2010. In 2012, the Upper Brushy Creek Water Control and Improvement District (WCID) initiated a flood protection plan that included watershed modeling. Communities within the watershed desired to use the modeling as the basis for a comprehensive mapping update. The WCID then partnered with FEMA and the Texas Water Development Board to complete the process.
- Where is this happening?
The updated maps encompass the Upper Brushy Creek Water Control and Improvement District (WCID) boundary, which includes much of southwest Williamson County.
- What is the general impact of new floodplains? Are more properties going to be in the floodplain?
In general, updated flood levels will increase, i.e., more properties are likely to be in the updated floodplain. When new maps are issued, your risk may have changed along with your flood insurance requirements. Property owners are encouraged to review the updated maps and discuss implications with their insurance agent. If you've been mapped into a high-risk area, you will be required to purchase flood insurance if your mortgage is through a federally regulated or insured lender. It is possible to save money through a process known as grandfathering provided by the NFIP.
If your property is mapped out of a high-risk area, your flood insurance costs will likely decrease.
- What does FEMA stand for?
Federal Emergency Management Agency - the operation of FEMA is to lead America to prepare for, prevent, respond to, and recover from disasters.
- What is a flood?
A flood is a general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of two or more properties from overflow of inland or tidal waters, from unusual and rapid accumulation or runoff of surface waters from any source, or from mudflow.
- What is a floodplain?
The Federal Emergency Management Agency (FEMA) defines a floodplain as a land area that is susceptible to being inundated by water from any source.
- What is the National Flood Insurance Program (NFIP)?
The NFIP is a Federal program enabling property owners in participating communities to purchase insurance protection against losses from flooding. This insurance is designed to provide an insurance alternative to disaster assistance to meet the escalating costs of repairing damage to buildings and their contents caused by floods.
Participation in the NFIP is based on an agreement between local communities and the Federal Government that states if a community will adopt and enforce a floodplain management ordinance to reduce future flood risks to new construction in Special Flood Hazard Areas, the Federal Government will make flood insurance available within the community as a financial protection against flood losses.
- How does the National Flood Insurance Program (NFIP) benefit the community?
Through the NFIP, property owners in the City of Cedar Park are able to insure against flood losses. Careful management of development in the floodplains results in construction practices that can reduce public and private flood losses. A major purpose of the program is to alert property owners to the danger of flooding and to assist them in reducing potential property losses.