The Flood Analysis Model was developed using two software programs: a reservoir and flow routing model called HEC-ResSim (developed by USACE) and a rainfall-runoff model called PRMS or Precipitation Runoff Modeling System (developed by USGS). Links to the general instructions and documentation for these software programs can be found below.

The HEC-ResSim model can be used to assess the impact of pre-event reservoir voids on flood crests. The PRMS rainfall-runoff model can be used to generate inflows to the HEC-ResSim model to evaluate the effects of development on flooding.

In February 2010, the documentation for both the HEC-ResSim and PRMS portions of the Delaware River Basin Flood Analysis Model were finalized. The supporting documentation explaining how the USACE’s HEC-ResSim model was developed and used for the Delaware River Basin as well as detailed information on the USGS PRMS model with supporting documentation can be downloaded using the links found below. A revised model and supporting documentation, based upon the independent external peer review, were posted in February 2012.

The HEC-ResSim model includes two inflow data sets: one derived using observed streamflow information called “FC-GageQ” and one simulated using the “FC-PRMS” software called PRMS. The “FC-GageQ” inflow data set better simulates what happened in the river during the three storm events and was used by the DRBC to assess the impacts of reservoir voids on flood crests. The “FC-PRMS” inflow data was generated with the rainfall runoff model, which produced less accurate inflows. Differences between the input data sets are further explained in the HEC-ResSim documentation (see also the independent external peer review).

In conjunction with the Flood Analysis Model results, DRBC staff used other tools such as USACE Inundation Mapping, USACE Structural Surveys, and the OASIS model to prepare the presentation Delaware River Basin: Analysis of Potential Flood Mitigation with Existing Reservoirs (pdf 3.5 MB) and the document Delaware River Basin Flood Analysis Model: Overview of Results and Next Steps (pdf 1.2 MB), both presented at the December 15, 2009 Delaware River Basin Interstate Flood Mitigation Task Force meeting.

Reports:

• USACE HEC-ResSim Model May 2011 Revised Report (pdf 7.5 MB)
  
  
• USACE HEC-ResSim Model Feb. 2010 Report (pdf 6.6 MB)
  
  
• USGS PRMS Model Report

Please note that it is highly recommended that individuals consult with a qualified engineer or hydrologist on the use of the model and interpretation of model results.

Computer Specs and Needs:

• Windows XP or Windows Vista
  
  
• At least 1 Gigabyte of RAM
  
  
• At least 10 Gigabytes of available disk space

There are three files that will need to be downloaded:

• Set-up Guide (pdf 276 KB) 
  
  
• HEC-ResSim Software with Lag and K Routing (60 MB)
  
  
• Delaware Basin Model Input Files (22 MB) March 2011 Revised Version
  
  
• Delaware Basin Model Input Files (36 MB) February 2010 Version

Please note that these files are large and may take some time to download; please refer to the Set-up Guide for installation instructions. The free program WinZip will be needed to install the Input Files on your computer.

On-Line Software References, including User's Guides, for Model Components (not specific to the Delaware Basin Model):

• PRMS Model
  
  
• HEC-ResSim Reservoir Modeling and Routing
  
  
• Lag and K Flow Routing Method, Based on That Used in Existing NWS Flood Forecasting Model 

For questions on the model, please contact:
Amy Shallcross, Water Resource Operations Manager, at 609-883-9500 ext. 232

DRBC does not provide technical support on how to use the models.
For technical support, please contact USACE-HEC or USGS.