HEC-WAT (Watershed Analysis Tool) is an integrated system of software, designed for interactive use in a multi-disciplinary environment. The system is comprised of a graphical user interface (GUI), data storage and management capabilities, mapping, graphics and reporting features.

The U.S. Army Corps of Engineers (USACE) conducts water resources management studies. These studies begin with the definition of problems, issues, and opportunities and continue with evaluation of impacts so that appropriate decisions may be made. The studies often require hydrologic, hydraulic, economic, environmental, and social impact analyses. For a study, coordination, file/data sharing, logistics, reporting of modeling results, and status reporting are often a problem for the modeling teams as well as project management staff. USACE determined that there was a need to streamline and integrate the tools commonly applied by the district and division offices to perform these analyses so that more efficient and coordinated modeling and planning could be performed.

Flood Risk Management

USACE flood risk management (FRM) policy requires that USACE analytical processes include methods and tools that employ integrated, comprehensive, systems and life-cycle based approaches and risk-based concepts in planning, design, construction, operations and major maintenance. These USACE methods need to incorporate the system response of projects when considering load distribution and failure possibilities. USACE policy also states that project performance needs to consider the system reaction to flood loading and how those loadings are distributed across the watershed.

HEC-WAT includes an option that analyzes complex riverine systems while implementing the flood risk management and systems requirements. The compute option, Flood Risk Analysis (FRA), allows a user to perform plan formulation or system performance analyses while incorporating risk and uncertainty analyses. The terminology, analysis procedures, and output for the FRA compute option are consistent with USACE guidance and requirements.

The purpose of the HEC-WAT software is to help USACE study teams perform the necessary hydrologic, hydraulic, environmental, and consequence planning analyses that are required for water resource studies. The HEC-WAT framework allows a multi-disciplinary PDT to perform water resources studies in a comprehensive, systems based approach by building, editing and running models commonly applied by multi-disciplinary teams and saving and displaying data and results in a coordinated fashion. The terminology, analysis procedures, and output used by HEC-WAT are consistent with the requirements of USACE guidance and policy. HEC-WAT is designed to facilitate:

• Entry of the appropriate data into each of the modeling programs is incorporated into the HEC-WAT framework.
  
• The analytical process and enhanced coordination among study team members, while producing more consistent results and displays.
  
• The definition of alternatives through schematic representations, model identification and sequencing, and tabular formats.
  
• The assessment of study status by reviewing HEC-WAT outputs and reports.
  
• The review of modeling results at all modeled locations without the direct knowledge of how the individual models generate those results. Those attending meetings can view the results system-wide rather than reading the results for a few locations in a hard copy report or poster.