State Water Resources Research Institute Program (WRRI)

Details for Project ID 2013LA92B, 2013

Development of Total Maximum Daily Load for Dissolved Oxygen in Nutrient-Enriched Lowland Rivers

Institute: Louisiana
Start Date: 2013-03-01 End Date: 2014-02-28
Total Federal Funds: $12,520 Total Non-Federal Funds: $25,040

Principal Investigators: Zhi-Qiang Deng

Abstract: DUE TO THE REDUCTION IN FUNDING FROM SEQUESTRATION, TASK 3 (Development of Total Maximum Daily Load (TMDL)) WILL BE DROPPED FROM THE PROJECT. I WILL COMPLETE TASK 1 AND TASK 2 DESCRIBED IN THE PROPOSAL BELOW. ---- Nutrient-enriched lowland rivers in Louisiana are largely impaired due to low dissolved oxygen. In fact, the Louisiana’s latest (2010) Integrated Report for water quality assessment indicates that about 45.7% of assessed rivers (155/339) are impaired due to low dissolved oxygen (DO) in terms of supporting fish and wildlife propagation (fishing). The US EPA requires states to develop Total Maximum Daily Load (TMDL) for pollutants causing impairments. While the DO load allocation requires the determination of sediment oxygen demand (SOD), the SOD in the organic-rich fluid mud (fluff) layer, commonly occurring in coastal Louisiana rivers, is rarely taken into account in TMDL development due to the lack of an effective modeling tool. The lack of an effective modeling tool for DO in nutrient-enriched lowland rivers causes high uncertainty in TMDL development and makes it challenging to restore impaired water bodies and thereby to comply with the Federal Clean Water Act. This is a critical regional and state water quality problem needing to be addressed. The overall goal of this project is to develop an efficient and effective modeling tool for determining spatial and temporal variations in DO in nutrient-enriched lowland rivers and thereby to address the critical regional and state water quality problem. The proposed strategy is to test and demonstrate the new modeling tool by developing the TMDL for DO in the Lower Tangipahoa River in southeast Louisiana. The Lower Tangipahoa River is on the latest US EPA and LDEQ 303(d) list for not supporting its designated use of fish and wildlife propagation due to low DO. Specific objectives of the project are: (1) to develop a new modeling tool, called VART DO-3L, for simulation of spatial and temporal variations in DO in nutrient-enriched lowland rivers. This objective will be addressed by the extension of the VART series of models developed by the PI’s research group; (2) to identify critical source locations of pollution in the Tangipahoa River watershed. This objective will be addressed by combining the results from the VART DO-3L model, ArcGIS maps and the Google Earth to show source locations of pollution along the Lower Tangipahoa River; and (3) to calculate the TMDL for DO in the Lower Tangipahoa River. This objective will be addressed by combining the VART DO-3L model, the load duration curve method, the watershed modeling tool BASINS/HSPF, GIS/Google Earth-based mapping, and observed data. The proposed project has broader implications for environmental restoration and sustainability in Louisiana and in the nation as well. This project will provide an efficient and cost effective modeling tool for environmental and water resources management agencies to determine instream DO more accurately due to the incorporation of SOD in the fluff layer commonly occurring in nutrient-enriched lowland rivers and thus reduce the uncertainty in TMDL development and implementation. While this project focuses on the Lower Tangipahoa River watershed, the approach to be developed in this study can be easily extended to other watersheds in Louisiana and in other low relief regions. In addition, the project provides research and educational training opportunities for graduate and undergraduate students. This proposal is intended to address the two research priorities: (1) Watershed Education and Research Activities and (2) Total maximum daily load (TMDL) calculations in Louisiana water bodies, identified by the Louisiana Water Resources Research Institute (LWRRI) in LWRRI’s Research Priorities for 2013.