Graphical representation of flood inundation for NWS flood categories are based on steady state hydraulic modeling of water surface elevations for incremented discharges. Map shows approximate inundation areas for given water surface elevations and should not be used for navigation or permitting or other legal purposes, but strictly as a planning reference tool.
The purpose of a flood forecast inundation map is to communicate flood risk based on best available information at the time of map development. This flood forecast inundation map has been compiled using the best information available and is believed to be accurate; however, its preparation required many assumptions. Actual conditions during a flood event may vary from those modeled in the map. The limits of flooding shown should only be used as a guideline for emergency planning and response actions. Actual areas inundated will depend on specific flooding conditions.
The risk of flooding behind flood risk management (FRM) structures (such as levees, floodwalls, closures, etc.) depends on many factors that cannot be entirely predicted in advance. These factors include whether the FRM structure overtops, length of time the structure overtops, and whether the overtopping leads to breach formation.
Two distinct approaches to mapping flooding behind FRM structures have been applied to best address the uncertainty, documented flood risk management systems and undocumented flood risk management systems. No specific level of protection is implied for any FRM structure depicted on these maps.
The mapping is based on the PASDA ground elevation data from 2006-2008.
Documented Flood Risk Management Structures (red lines) – Includes Wyoming Valley FRM project. Area behind the FRM structures is not shown as being flooded until the structure is over-topped.
Documented Flood Risk Management Risk Area (yellow shaded area) - Shows the area with flood risk reduced by documented flood risk management structures
Undocumented Flood Risk Management Structures (orange lines) – Includes Duryea and Mill Creek FRM projects. Area behind FRM structures is shown as flooded, although the structure may provide some level of flood risk reduction
Undocumented Flood Risk Management Risk Area (pale orange shaded area) – Shows rough approximation of FRM area that would have flood risk reduced by the undocumented flood risk management structure if it functions properly
In the Wilkes-Barre to Hanover Township Reach of the Wyoming Valley Flood Risk Management Project, the flood inundation map shows that overtopping of the levee will occur at Flood Stage 43.2 feet in the downstream portion of the reach. With respect to public safety, inundation is conservatively shown as occurring behind the entire length of the reach. Some data suggests that overtopping of the levee may not occur at the stage 43.2 feet. This issue is being investigated and the flood inundation mapping for the Wilkes-Barre to Hanover Township Reach may change as a result.
The detailed project report can be found here
If you have questions related to any of the flood risk management projects in Luzerne County, call the Luzerne County Flood Protection Authority at 570-208-6100.