Floods are the most common natural disaster in the United States. To reduce the impacts of flooding on communities, the Federal Emergency Management Agency (FEMA) requires communities to manage development in floodplains and publishes maps of floodplains. These maps are used 1) by the City to manage development through our Community Development Code (CDC) and 2) by lending institutions and companies that offer flood insurance under the National Flood Insurance Program. FEMA requires local governments to manage floodplain development in order reduce flood damages and for property owners to be eligible for public flood insurance.
FEMA last updated the flood maps for all of Washington County in 2018. Also, the City recently requested that FEMA approve some corrections to flood maps for Glencoe Swale, in the northwest portion of Hillsboro. FEMA has approved our request, and these changes went into effect on April 25, 2019. CLICK HERE to obtain a copy of the approved Letter of Map Revision (LOMR).
What is a floodplain?
The term “floodplain” is shorthand for the area that has a 1% chance of flooding in any given year (aka, the “100-year flood event”). The City calls this area the Regulatory Floodplain in keeping with our CDC Regulatory Floodplain Overlay (RFO). FEMA calls this area the Special Flood Hazard Area, and there are a number of codes that provide managers with more information about the type of flooding or flood study; AE is the most common type of FEMA floodplain in Hillsboro.
Note that the outer floodplain boundary indicates an annual probability of flooding of AT LEAST 1%; the closer a property is to a waterway, the greater the likelihood of it flooding. This YouTube video has a great explanation.
How do I determine if a structure or property is in the floodplain?
FEMA provides online access to flood maps here. However, it’s still a good idea to contact the City Floodplain Administrator, Sarah Bruce, at 503-681-6214 or firstname.lastname@example.org (please give the address).
The requirement to carry flood insurance is based on a property containing buildings that touch the floodplain. There is greater than a 1 in 4 chance that a home in the floodplain will be flooded during a 30-year mortgage, 27 times more likely than a fire.
Flooding can and does occur outside of the floodplain, although it is less likely. Flood insurance for buildings not in a mapped floodplain is much less expensive than policies for buildings that are in a floodplain, and worth having if you’ve had issues with water inundation from storms.
Conventional homeowners’ and renters’ insurance policies do not cover flood losses.
How might changes to floodplain maps affect me?
- Certain areas of the City may be brought into the Regulatory Floodplain, and structures within the Regulatory Floodplain would be subject to the requirement to carry flood insurance.
- Certain areas of the City may be removed from the Regulatory Floodplain, and structures in those areas may no longer be required to carry flood insurance. (It’s up to the mortgage lender, though.)
- Rates on flood insurance premiums may change.
More about flood insurance
There are potentially discounted premiums for buildings that are “newly mapped” into the floodplain. Flood insurance is available for personal property as well as for structures. Flood insurance premiums can vary based on characteristics of the structure, such as its elevation.
Visit FloodSmart.gov to learn more about insurance, premiums, and ways to lower rates. Flood insurance is available and advisable for buildings that are prone to flooding regardless of whether a lender requires it or whether the official FEMA maps show the property as within the regulatory floodplain.
Development and flood risk
The City has been using the 2016 flood maps to evaluate and manage new development since their release as preliminary data in the mid-2000s. The City also requires a 1-foot “freeboard,” or margin of safety, for buildings in the floodplain, which further helps reduce flood damages.
- CDC Regulatory Floodplain Overlay (RFO) section
- FEMA Flood Map Service Center
- Hillsboro Maps online portal (in Hillsboro Maps, click on the Planning arrow in the left-hand sidebar to view flood maps)
- Need an Elevation Certificate? Click here to find a Professional Land Surveyor!
For more information, contact Sarah Bruce, Floodplain Administrator, by email at email@example.com or by phone at 503-681-6214.