Oak Orchard Flood Risk Visualization Map - Water Depths Associated with 100-Year Flood Event

Oak Orchard base map Oak Orchard overlay map

Slider Image KeyThe flood map is shown with an interactive before/after slider tool that enables the viewer to visualize both the landward (horizontal) extent of flooding and floodwater depths (vertical) expected to occur during the 100-year flood (or 1 percent annual chance flood event).  Data for the 100-year floodplain was obtained using FEMA’s preliminary flood maps, and floodwater depths have been provided by Delaware DNREC through a project with AMEC, a London-based engineering company.

You can also explore what this area looked like during a 1998 northeaster.

What is a 100-Year (or 1 percent annual chance) flood?

Large floods are often designated as 100-year flood events, but the term 100-year flood does not mean that such a flood occurs once every 100 years.  Instead, it means that there is a 1 percent or greater chance of a major flood occurring in an area during any given year. In fact, two 100-year floods could occur a year apart or even a month apart.

Another way of considering the 1 percent annual chance of flooding is that the 100-year flood has a 26 percent chance of occurring during a 30-year period, the length of many mortgages. Learn more >

Flood Basics - What you should know about flood risk

  • Floods can happen anywhere, at any time. You do not need to live near water to be flooded.
  • Just a few inches of water from a flood can cause tens of thousands of dollars in damage.
  • A property in the 100-year (1 percent annual chance) flood zone or Special Flood Hazard Area (SFHA) is land at a high risk of a major flood.
  • A property in a SFHA has a 1 in 4 percent chance of experiencing a flood during the lifetime of a 30-year mortgage.
  • Floodwaters don’t stop at a line on a flood map. You may not be required to buy flood insurance, but your home could still be at risk for flooding.
  • It doesn’t have to rain or storm to cause flooding. A flood is defined as an inundation of two or more properties, or two or more acres of normally dry land. Floods can result from, but are not limited to, overflow of inland or tidal waters, runoff of surface waters, mudflow, broken water mains, or even backed-up storm drainage systems.
  • More than 20 percent of flood insurance claims come from people outside of mapped high-risk areas.
  • Most homeowners insurance doesn’t cover floods. Only a flood insurance policy will cover flood damage. 

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Page Updated on October 28, 2014