New York Model

Water Quality and Hydrodynamic Modeling Software

Our modeling group has been at the forefront of developing and applying mathematical models to address the impacts of pollutant discharges on water quality and ecosystem health. In addition to applying water quality models, our modeling staff has long been recognized nationally as innovators and developers of water quality modeling tools and computer codes.

Many of the computer codes developed have become the common frameworks used by many in the modeling community. Currently, we provide two open-source models that are available to the modeling community as presented below. 

To download the software, agree to the software license agreement and complete the form; you will receive the zipped file to download for use.

Model Descriptions


Estuarine, Coastal Ocean Model with Sediment Transport is a 3D hydrodynamic and sediment transport model developed by our modeling staff starting from the Princeton Ocean Model for application to marine and freshwater water bodies. The ECOMSED model calculates water movement (flow, depth, velocity, dispersion) due to river inflow, tides, meteorological forcings and includes salinity, temperature and tracer parameters. In addition, the ECOMSED model is also used to complete cohesive and non-cohesive sediment transport calculations for contaminated and clean sediment investigations. 

The movement and mixing of wastes introduced into marine and freshwater environments are controlled by the circulation characteristics of the water body. To predict the circulation characteristics, the hydrodynamic transport processes must be defined by various hydrographical (runoff), meteorological (surface wind, heating/cooling), adjacent open ocean (large-ocean circulation offshore), astronomical (tides) and internal (gradients) forcing mechanisms. Our modeling staff have developed and applied steady-state, 2D and 3D time dependent models to compute hydrodynamic circulation. In recent years, scientists and engineers have come to rely on hydrodynamic circulation to provide the necessary ingredients (i.e., currents and dispersion) for use in water quality modeling, thermal evaluations and sediment transport studies.

The development of ECOMSED has its origins in the mid-1980’s with the creation of the Princeton Ocean Model (POM) followed by an upgraded version called ECOM for shallow water environments such as rivers, lakes, estuaries and coastal oceans. In the mid-1990s, concepts for sediment resuspension and settling developed by W. Lick at the University of California, Santa Barbara were incorporated within the ECOM modeling framework that resulted in the current version, ECOMSED.


RCA (Row Column Advance Ecological Systems modeling Program, AESOP) is a generalized water quality/ecosystem model, built on the WASP framework (originally developed by HDR modeling staff) that is capable of being linked to the ECOM hydrodynamic model.  The RCA model includes pathogen kinetics; full eutrophication kinetics to model nutrients, algae, light and dissolved oxygen including a sediment flux submodel that calculates sediment nutrient fluxes and sediment oxygen demand as a function of settled organic matter.  The RCA model is routinely used for CSO/SSO pathogen fate and transport studies and complex nutrient assessments in estuaries, rivers and lakes.  Download here à

RCA is designed to execute in conjunction with HDR's hydrodynamic modeling code, ECOMSED, so that output from the ECOMSED model is directly linked to RCA. The two models share the same numerical grid structure and underlying numerical solution techniques.  Recently, the RCA model has been linked to the EPA-supported EFDC hydrodynamic model.

The development of RCA has its origins in the mid-1980’s, but can trace its lineage back to the EPA-supported water quality model WASP, which was developed in the early 1970's by HDR modeling staff. RCA follows, in concept, the idea of developing problem or site-specific kinetic subroutines to address a myriad of water quality problems. The current release of RCA, available here, includes kinetic subroutines for pathogen modeling, eutrophication modeling, computation of residence time, and a "10s" test, which permits the user to verify the integrity of the hydrodynamic model circulation transfer. Users are also permitted to develop their own problems or site-specific kinetic subroutines.

Download the Software

Read and download the software license agreement.

Software License Agreement

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