DRBC staff develops, utilizes and applies various models to help manage, protect and improve Basin water resources.

Water Quality Models

• The DRBC developed three-dimensional estuary hydrodynamic and water quality models for the Delaware River Estuary and Bay under the guidance of a model Expert Panel. Completion and calibration of the eutrophication model (linked hydrodynamic and water quality models) allow for the evaluation of attainable aquatic life designated uses and associated dissolved oxygen criteria for Zones 3, 4 and Zone 5 through load and waste load allocations in the estuary. Learn more about DRBC's Aquatic Life Designated Use Study.
  
  
• CORMIX Models are used to determine mixing zones for total dissolved solids, toxic pollutants and heat dissipation areas for regulated discharges. These models support DRBC Project Review and NPDES permitting programs.
  
  
• Models are used for assimilative capacity determinations for a water quality parameter of concern.
  
  
• Models are used for TMDL development to support Basin states and the U.S. EPA.
  
  
• Models perform No Measurable Change evaluations for discharges in Special Protection Waters.

Emergency Response

• A real-time flow and transport model, which is run nightly and tracks the movement of water in the tidal Delaware River. If a spill occurs, the most recent model run can be used along with a water quality model to predict where the pollutant will go and what the concentrations will be. This is especially important to protect drinking water intakes in the tidal Delaware River.

Flow Management Modeling

• The DRBC's DRB-PST Model is a daily flow model used to evaluate flow management alternatives in the Basin, study salinity intrusion and support decree party negotiations.
  
  
• The DRBC's three-dimensional hydrodynamic model (also referred to as the salinity model) is used to evaluate the effects of sea level rise on salinity in the Delaware River Estuary.
  
  
• The DRBC is working to extend a USACE HEC-RAS model is currently uses for the upper Delaware River to the entire non-tidal Delaware River and select tributaries. The model will be used to evaluate water quality, temperature and habitat under varying flow management scenarios.
  
  
• The DRBC's REF-DSS modeling evaluates how reservoir releases and flow management protocols affect water quality and available habitat.

• The DRBC is working with USACE Philadelphia District to recalibrate HEC-HMS, a hydrologic model, with low flow periods. The recalibrated model will be used with output from General Circulation Models (GCMs, or climate models) to generate future hydrology for use with DRB-PST for evaluating future flow management programs and operational goals for multi-objective water resource management.

Water Supply Planning

• The DRBC is developing a hydrologic watershed model to evaluate water stressors such as growth of population centers, the effects of land-use change, water use and the effects of climate variability and climate change on water resources in the Basin.

• Pennsylvania Coastal Resources Management Program: Sea Level Rise and Associated Effects in the Delaware Estuary Coastal Zone (DECZ) (pdf; September 2022; prepared by DRBC Water Resource Operations)
  
  
• Water Quality Model for Carbon and PCB Homologs for Zones 2-6 of the Delaware River Estuary (pdf; May 2011)
  
  
• TMDL for PCBs for Zone 6 of the Delaware River (pdf; prepared by the DRBC for USEPA Regions II & III; Dec. 2006)
  
  
  • DRBC Final Report: PCB TMDL for DRBC Zone 6 (Delaware Bay) Established (pdf; Dec. 2006)
    
    
  • TMDL for PCBs for the Delaware Bay: DRBC Zone 6 (pdf; presentation given by DRBC staff at Sept. 26, 2006 public meeting in Dover, Del.)
    
    
• Revised Calibration of the Water Quality Model for the Delaware Estuary for Penta-PCBs and Carbon (pdf; Sept. 2006)
  
  
• Development and Calibration of a Hydrodynamic Model of the Tidal Rancocas Creek (pdf; May 2006)
  
  
• TMDLs for PCBs for Zones 2-5 of the Tidal Delaware River (pdf; prepared by the DRBC for USEPA Regions II & III; Dec. 2003)
  
  
  • DRBC Final Report: TMDLs for PCBs For Zones 2-5 of the Tidal Delaware River Established (pdf)
    
    
  • DRBC DYNHYD5 Hydrodynamic Model (Version 2.0) and Chloride Water Quality Model for the Delaware Estuary (pdf)
    
    
    • Appendix A: Hydrodynamic Model Input File (pdf)
      
      
    • Appendix B: Chloride Model Input File (pdf)
      
      
    • Appendix C: Tidal Heights Calibration Results (pdf)
      
      
    • Appendix D: Boatrun Chloride Calibration Results (pdf)
      
      
  • DRBC PCB Water Quality Model for the Delaware Estuary (pdf)
    
    
• Executive Summary to the Public Hearing Response Document on the Proposed Determination Regarding the Assimilative Capacity of the Tidal Delaware River for Volatile Organics and Toxicity (pdf; 2000)
  
  
• Wasteload Allocations for Volatile Organics and Toxicity: Phase I TMDLs for Toxic Pollutants in the Delaware River Estuary (pdf; 1998)
  
  
• Development of a Hydrodynamic and Water Quality Model for the Delaware River (prepard by HydroQual, Inc. for the DRBC; pdf; 1998)
  
  
  • Development of a Hydrodynamic and Water Quality Model for the Delaware River: Appendices A & B (prepard by HydroQual, Inc. for the DRBC; pdf; 1998)
    
    
• Implementation Policies and Procedures: Phase I TMDLs for Toxic Pollutants in the Delaware River Estuary (pdf; 1995)