ASCE Central - March Technical Dinner Meeting 

NRCS Unit Hydrograph Peak Rate Factors for NJ

This research calibrates the peak flow peaking coefficient as part of the Natural Resources Conservation Service’s (NRCS) Unit Hydrograph equation to determine regional differences in the value throughout the state of New Jersey.  The peak flow is an important parameter in design of hydraulic structures. The NRCS provides a method to produce a synthetic unit hydrograph, which determines this parameter. The NRCS method is the most widely used method throughout the engineering community for design storm analysis and predictions.

According to the NRCS, the peak factor was not intended to remain constant, but instead should change based on regional topographic effects and watershed characteristics.  However, this value has been incorrectly assumed constant by most members of the hydrologic engineering community.  To provide more accurate peak flow estimates, historical storm hydrograph data were analyzed and converted to a unit hydrograph using accepted engineering practices.  Once the unit hydrograph was found, the peak flow and corresponding time to peak were used with the watershed area in order to calculate the corresponding peaking factor. The study focused on watersheds with areas ranging up to 20 square miles.  Additionally, historical storm hydrograph analysis was limited to storms producing peak flows at or greater than a 25 year return period.

The results of the analysis show there to be a high degree of variation of peak rate factors both at a specific watershed where multiple storms were analyzed as well as regionally throughout the state of New Jersey.  Peak rate factors varied between approximately 100 and 900.

March 19th at The College of New Jersey, 2000 Pennington Rd, Ewing, NJ 08628

Education Building - Room 212 (campus map).

Parking lot available outside the Education Building

Doors will open at 6:00 PM, Dinner at 6:30 PM, Presentation at 7:00 PM ending at 8:00 PM. 

Presentation approved by NY State (PIE) for 1 PDH

About the Presentor

Dr. Michael Horst PE is an Associate Professor and the Chair of the Civil Engineering Department at The College of New Jersey.  Dr. Horst's specialties are in applied water resources engineering, specifically open channel flow hydraulics, storm water management, and engineering hydrology.  He has been teaching since 2006 and has worked as a professional consultant for the Hydraulics Research Lab of the Federal Highway Administration since 2004.  

For more information, visit Dr. Horst’s website at http://www.tcnj.edu/~horst/