CE-QUAL-RIV1:
One-dimensional, dynamic flow and water quality model for streams

U.S. Army Corps of Engineers | Engineer Research and Development Center | Environmental Laboratory | Search EL

Distributor: Thomas M. Cole
Environmental Laboratory
U.S. Army Engineer Waterways Experiment Station
3909 Halls Ferry Road
Vicksburg, MS 39180
tcole@lasher.wes.army.mil

CE-QUAL-RIV1 is a one-dimensional (cross-sectionally averaged) hydrodynamic and water quality model, meaning that the model resolves longitudinal variations in hydraulic and quality characteristics and is applicable where lateral and vertical variations are small. CE-QUAL-RIV1 consists of two parts, hydrodynamic and water quality. Each of these parts is a separate computer code (RIV1H, the Hydrodynamic code and RIV1Q, the water Quality code). The hydrodynamic code is applied first to predict water transport and its results are written to a file which is then read by the quality model. It can be used to predict one-dimensional hydraulic and water quality variations in streams and rivers with highly unsteady flows, although it can also be used for prediction under steady flow conditions.

RIV1H predicts flows, depths, velocities, water surface elevations and other hydraulic characteristics. The hydrodynamic model solves the St. Venant equations as the governing flow equations using the widely accepted four-point implicit finite difference numerical scheme.

RIV1Q can predict variations in each of twelve state variables: temperature, carbonaceous biochemical oxygen demand (CBOD), organic nitrogen, ammonia nitrogen, nitrate + nitrite nitrogen, dissolved oxygen, organic phosphorus, dissolved phosphates, algae, dissolved iron, dissolved manganese, and coliform bacteria. In addition, the impacts of macrophytes can be simulated. Numerical accuracy for the advection of sharp gradients is preserved in the water quality code through the use of the explicit two-point, fourth-order accurate, Holly-Preissman scheme.

The model that serves as the basis for CE-QUAL-RIV1 was originally developed at Ohio State Uni-versity at the request of the U.S. Environmental Protection Agency (EPA) for the purpose of predicting water quality associated with storm water run-off. Researchers at the U.S. Army Engineer Waterways Experiment Station (WES) were attracted to the model because it was fully dynamic for determining flow and water quality and it had several desirable numerical features, such as a two-point fourth-order scheme for accurately predicting the advection of water quality concen-trations. The WES con-tracted Ohio State University to modify the model code to handle control structures. This modification, along with the unsteady flow feature, gave the model the versatility needed for simulating Corps of Engineers regulated stream/waterway projects. Subsequently, the updated version was tested at WES, and addi-tional modifications and cor-rections were made, resulting in Version 1.0 of CE-QUAL-RIV1, released in 1991. WES further modified and supported CE-QUAL-RIV1, releasing Version 2.0 of the model in 1995 (Environmental Laboratory 1995).

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Web Date: December 1997
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