Will this site flood again?
It is likely that this site will see flooding again at some point in the future.
How often will this site flood again?
This is very difficult to predict as it depends on rainfall over a large area, or very heavy rainfall over a smaller area. But for the areas within the Special Flood Hazard Area (Zone AE), there is a 1% chance in any given year that it will experience flooding.
How far up into the site does the current 100-year floodplain go?
The SFHA (Zone AE) extends North into the parking lots South of Anderson Avenue, in front of the buildings that house the Midwest Dream Car Collection and Powercat Sports Grill.
How far up into the site does the future 100-year floodplain go?
The future conditions floodplain extends further North towards Anderson Avenue but does not impact Willie’s Tire and Lube or Landmark Bank.
What is the difference between the current 100-year floodplain and the future 100-year floodplain?
The 100-year floodplain is that area that has been analyzed with current conditions and is predicted to be impacted by the 1% flood, or the area that has a 1% chance in any given year of being inundated with flood waters. The future conditions floodplain takes into account future development within the watershed to predict how the floodplain boundary will increase as impervious surfaces increase in the watershed.
Is it legal to develop within a floodplain?
The floodplain management requirements adopted by the City of Manhattan allow for development in the floodplain as long as specific conditions regarding lowest flood elevations and floodproofing requirements are met.
Are there additional requirements to developing land within a floodplain?
Manhattan has a requirement that compensatory storage must be developed for any fill that is placed in the floodplain.
Will development on this site make flooding along Wildcat Creek worse?
Because of the proximity to a large road embankment downstream of the site, and the abandoned railroad embankment between the site and Wildcat Creek, additional fill or structures within the site does not appear to have a negative impact on flooding associated with Wildcat Creek on the site or on properties adjacent to the site.
Will stormwater detention/retention ponds on this site improve flooding along Wildcat Creek?
Detention or retention ponds will help reduce stormwater impacts on the site, but will not have much of an impact on flooding on the site associated with Wildcat Creek.
What does it mean to have a ‘resilient’ development that is designed to withstand flooding?
Resiliency, or resilient development, means development that is designed to withstand the impacts of future flood events. Typically, this means the structure (or landscape) is mitigated against a minimum 1-percent annual chance flood event. It could also be more stringent to protect against more common stormwater or pluvial events. Examples of resilient flood development include elevating the lowest floors and building access above flood design levels, designing a structure such that water will not enter the building (e.g., floodproofing), or incorporating a sacrificial first floor that is designed to take on water without impacts to the structure or its contents. The central idea of resiliency is to be able to return to a property after a flood event with a decrease to the economic and social impact of the flood event.