Water Resources Research Act Program

Details for Project ID 2020LA019B

Identification of Critical Sources and Loadings of Nutrients for Reducing Harmful Algal Blooms in Lake Pontchartrain

Institute: Louisiana
Year Established: 2020 Start Date: 2020-02-28 End Date: 2021-02-26
Total Federal Funds: $15,100 Total Non-Federal Funds: $30,310

Principal Investigators: Zhiqiang Deng

Abstract: Harmful Algal Blooms (HABs) and particularly toxic cyanobacterial harmful algal blooms (CyanoHABs) have become a growing concern to communities living around Lake Pontchartrain because CyanoHABs pose a growing threat to human and aquatic ecosystem health and cause economic damages. While extensive efforts have been made over the past decades to address CyanoHAB problems in Lake Pontchartrain and beyond through the development of Total Maximum Daily Load (TMDL) and the implementation of a suite of Best Management Practices (BMPs), CyanoHABs are still increasing in the frequency and extent. This is a critical national and state water quality problem needing to be addressed. The key to reducing CyanoHABs is to reduce excessive nutrient (primarily nitrogen and phosphorus) loadings from watersheds and particularly from critical source areas of nutrients to Lake Pontchartrain. The overall goal of this project is to demonstrate a new adaptive water quality management approach, called critical source areas-based dynamic TMDL development and implementation, to the prevention or at least reduction of CyanoHABs in Lake Pontchartrain and the sustainability of designated uses of Louisiana water bodies, addressing the critical regional and state water quality problem. The proposed strategy is to test and demonstrate the new watershed based dynamic water quality management approach by developing TMDLs for nutrients in Lake Pontchartrain that is impaired due to more and more frequent occurrence of CyanoHABs. The specific objectives of this project are (1) to identify the critical source watershed and critical source areas of nutrients in Lake Pontchartrain Basin and estimate watershed loadings of nitrogen and phosphorus into Lake Pontchartrain under changing land use and land cover conditions in the basin, and (2) to determine the optimum combination of BMPs for implementation of the TMDLs and thereby for achieving designated use of Lake Pontchartrain under dynamic nutrient loadings. The objectives will be achieved by combining satellite remote sensing data and watershed modeling tools including HSPF (Hydrologic Simulation Programming-Fortran) model and SWAT (Soil & Water Assessment Tool) model. The proposed project is of broader implications for environmental restoration and water resources sustainability in Louisiana and beyond. This project will provide a new dynamic approach for environmental and water resources management agencies to identify critical source areas of excessive nutrient loadings triggering CyanoHABs and thereby to restore designated uses of impaired water bodies. While this project focuses on Lake Pontchartrain and its critical watershed, the adaptive water quality management approach to TMDL development and implementation can be extended to other waterbodies and their watersheds in Louisiana and beyond. In addition, the project provides potential research and educational training opportunities for graduate and undergraduate students. This proposed project is intended to address the two research priorities: (1) Total maximum daily load (TMDL) (particularly excessive nutrient loading) calculations in Louisiana water bodies and (2) Adaptive management of Louisiana’s water resources (particularly mitigation of hypoxia), identified by the Louisiana Water Resources Research Institute (LWRRI) in LWRRI’s Research Priorities for 2020.