Mill Creek Watershed

The work described in this technical memorandum aims to analyze the downstream effects of the proposed Mill Creek reservoir. The 2006 preliminary engineering report did not evaluate downstream effects, rather focused on hydraulic and hydrologic reservoir characteristics and on examining the potential benefit to potable water service.

During this project, the Institute developed a hydrologic model to evaluate downstream impacts resulting from the implementation of the Mill Creek reservoir, such as potential flow reduction in the Calcasieu River during storm events and corresponding changes in water levels. The Institute utilized the United States Army Corps of Engineers (USACE) Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) to evaluate local hydrology. This modeling software is a standard analysis software used by the Federal Emergency Management Agency (FEMA) and the USACE, and it is the industry standard for hydrologic studies. The modeling software is free and open source and includes many pre- and post-processing and visualization tools (USACE, 2022).