Water Quality Model Capabilities
The U. S. Army Corps of Engineers (USACE) is building new water quality simulation and analysis capabilities within existing river, reservoir, and watershed runoff simulation programs (HEC-RAS, HEC-ResSim, and HEC-HMS), which are
widely used by USACE and other organizations. These capabilities will support the need for cost-effective science-based ecosystem restoration, management, and impacts assessment. Ecosystem Restoration is one of the primary missions
of USACE. The purpose of USACE ecosystem restoration activities is to restore significant ecosystem function, structure, and dynamic processes that have been degraded. Ecosystem restoration efforts involve an examination of the
problems contributing to the system degradation and the development of alternative means for their solution. The intent of restoration is to partially or fully reestablish the attributes of a natural, functioning, and self-regulating
system. Restoration opportunities associated with wetlands, riparian, and other floodplain and aquatic systems are likely to be most appropriate for USACE involvement. Authorities through which USACE can participate in the study,
design and implementation of ecosystem restoration projects include: 1) Section 206, Aquatic Ecosystem Restoration; 2)
Section 1135, Project Modifications for Improvement of the Environment; and 3)
Section 204, Beneficial Uses of Dredged Material; and 4) Studies specifically authorized by Congress, pursued under Investigations.
The Hydrologic Engineering Center (HEC) has a long history of developing software to solve flood control, navigation, and sediment problems faced by USACE. USACE districts have set up, calibrated, and applied many HEC models on rivers
and watersheds within their operational areas. The U.S. Army Engineer Research and Development Center’s Environmental Laboratory (ERDC-EL) has been developing nutrient, contaminant, and riparian vegetation modules that are able to be
fully integrated with a multitude of hydraulic and hydrologic models. The current collaboration between HEC and ERDC-EL is intended to extend the HEC models to include water quality and ecosystem simulation capabilities to support ever
increasing USACE needs for evaluating ecosystem management conditions and project alternatives.
Purpose
ERDC-EL partnered with HEC to build new environmental quality modeling capabilities in HEC-RAS, HEC-ResSim, and HEC-HMS. HEC and ERDC-EL have developed a water quality engine and are developing user interface components that will handle
the water quality data (meteorology, bathymetry, water quality loadings), compute the hydrodynamics, and communicate with each HEC program and the ERDC-EL water quality modules. Plug-ins have been developed for HEC’s Watershed
Analysis Tool (HEC-WAT) to support automated simulation of the 2D hydrodynamic water quality model, CE-QUAL-W2, and the water quality capabilities of HEC-RAS. The plug-ins allow modelers to run multiple separate models in sequence
and optionally link the outputs of one model with the next model to create an integrated watershed water quality modeling system. The water quality capabilities in HEC-RAS, HEC-ResSim, and HEC-HMS can be leveraged within HEC-WAT
for integrated planning studies and environmental analyses.
HEC-RAS simulates river hydraulics and sediment transport, computing river velocities, stages, profiles, and inundated areas. One-dimensional (1D) water quality capabilities have been developed and are being extended to simulate
water quality in river reaches. The cost to stake-holders interested in modeling water quality and interactions of flow, temperature, nutrients, dissolved oxygen and algae for improved riverine ecosystem management and restoration
is dramatically reduced due to leveraging these analyses against existing modeling efforts.
HEC-ResSim simulates reservoir operations, computing releases and downstream hydrographs. Water quality capabilities are being developed to allow inclusion of environmental objectives in the reservoir operation decision-making
process, as well as supporting watershed-scale ecosystem assessment and management. The new capabilities enable real-time simulation of temperature and water quality (dissolved oxygen, nutrients, carbon, algae, etc.) in reservoirs,
where stratification is an important factor.
HEC-HMS simulates hydrologic processes, computing flow into rivers and reservoirs. Water quality capabilities are being developed to compute runoff temperature and generalized conservative and non-conservative constituent
concentrations. The quantity and quality of runoff computed by HEC-HMS for the upland watershed will provide vital inputs for HEC-RAS, HEC-ResSim, and other models.
The water quality and riparian vegetation simulation and analysis capabilities developed in HEC-RAS, HEC-ResSim, and HEC-HMS will support the Corps’ needs for cost-effective science-based ecosystem restoration, management,
and impacts assessment. USACE is building or updating HEC models for 201 watersheds to support real-time simulation in the Corps Water Management System (CWMS). The water quality capabilities will leverage these models to build
integrated watershed-scale water quality simulation systems for real-time operations. These CWMS models can be rapidly converted to HEC-WAT models for application in watershed planning and impact analysis studies. The new
capabilities will streamline water quality model preparation and application, increasing efficiency and reducing costs while encouraging a watershed-scale approach to environmental restoration and management.
Contacts
ERDC POC:
Dr. Todd Steissberg
Phone: 530-219-7990
Email: Todd.E.Steissberg@usace.army.mil
HEC POC:
Ms. Lea Adams
Phone: 530-302-3680
Email: Lea.G.Adams@usace.army.mil
Last Updated: Sep 19, 2024