Water Resources Research Act Program

Details for Project ID 2014LA97B

Adaptive management of Catahoula Lake for Sediment Mobility and Control of Woody Encroachment

Institute: Louisiana
Year Established: 2014 Start Date: 2014-03-01 End Date: 2015-02-28
Total Federal Funds: $15,000 Total Non-Federal Funds: $31,668

Principal Investigators: Richard Keim, Brandon Edwards

Project Summary: Woody encroachment has been occurring in Catahoula Lake, Louisiana, for approximately 70 years in response to changes in hydrology following the implementation of water control projects in the region. The specific trigger for ecosystem conversion is unknown, and efforts to manage encroachment have met with limited success. The lake provides valuable habitat for waterfowl and other migratory birds, but the proliferation of woody seedlings in the lake bed has degraded high value herbaceous communities. The objective of this work is to design an adaptive water management strategy to help prevent further establishment of woody shrubs. To accomplish this goal, we propose to construct a stochastic hydrodynamic model to optimize water level management for maximum wave induced bed stress and sediment mobility in the lake. Fluid stress on vegetation has been shown to limit vegetation density through uprooting and substrate failure, and available models of thresholds suggest that waves in the lake are of sufficient size to induce critical levels of stress. The lake can generally be considered a shallow water environment, and linear wave theory can be used to approximate the wave field for a given combination of water level and environmental conditions. Field investigations of force needed to uproot woody seedlings and sediment size distribution in the lake will be used to develop site specific uprooting thresholds. A water management strategy based on stochastic scenarios of wind, water level, and resulting hydrodynamic conditions for the lake will provide managers with an adaptive tool to proactively control new establishment of woody seedlings.