Assessing Flooding and Hydrodynamics for Improved Stormwater Management





Natchitoches, Louisiana

Natchitoches is a small city in the northern Louisiana parish of Natchitoches. Colonized by the French in the early 1700s, the community was named after the indigenous Natchitoches people and served as a French outpost on the Red River for trade with Mexico. Following the Louisiana Purchase in 1803, cotton plantations expanded in the areas along the river—freight transported cotton to Texas and fueled a population boom. Downtown Natchitoches contains numerous historic buildings and is nationally recognized as a Preserve America Community. After the course of the river changed, cutting Natchitoches off from its reliable connection to the Mississippi River, the Cane River formed in its remnants. The eastern part of the city sits within a crescent bend of the Cane and is susceptible to flooding during heavy storm events.

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The Challenge

Frequent flooding of homes and businesses

The project area lies in a relatively confined area between the Red River and Cane River Lake that was once a branch of the Red River. It has historically been used in agriculture due to the rich soil deposited over centuries of river flooding. In the past 50-75 years there has been significant commercial and residential development.  What was once a large area of open or agricultural land is experiencing development including a large number of streets, structures and large paved parking lots. Because of insufficient and uncoordinated planning of storm water management, the area experiences frequent flooding problems. The general purpose of this project is to identify the principal causes of the flooding and to develop a plan of action to address the problem in an environmentally positive manner.

The Results

A hydraulic and hydrologic model of Natchitoches parish

The primary output of this project is a hydraulic and hydrologic model of Natchitoches parish. This was shared with the community in final form as a summary report detailing outputs, conclusions and underlying methodology. The H&H model itself was also transferred to the community for manipulation and use beyond the project.

This Thriving Earth Exchange collaboration is the first step of a longer-term effort by Natchitoches to ultimately develop and implement a flood management plan for the improvement of quality of live and economic benefits for residents and businesses in the community. The modeled hydrology and hydraulic conditions of the project area allows Parish leaders to move forward with the pursuit of other planned outputs, including:

  • Exploring potential infrastructure improvements to improve storm water management
  • Identifying costs and funding sources for infrastructure improvements
  • Revising existing planning and zoning ordinances to direct future development
  • Creating a body of local support for plans and actions