Climate change impacts on water quantity and quality of a watershed-lake system using a spatially integrated modeling framework in the Kissimmee River – Lake Okeechobee system

Abstract

Study RegionLake Okeechobee and its drainage basins, the Northern Lake Okeechobee (NLO) watershed, have faced climate variability and changes. The frequencies and magnitudes of extreme weather events are projected to increase in the future, and the impact of climate change on hydrological changes in upstream watersheds would significantly affect the water quality of downstream waterbodies. A holistic, system-wide modeling approach is necessary for a watershed–lake system. Study FocusThis study evaluated the impacts of climate change on the water quantity and quality of the NLO watershed–Lake Okeechobee system using a spatially integrated modeling framework combining watershed loading and receiving waterbody models together. Future climate projections and water level operation scenarios were incorporated into the modeling to investigate how the watershed–lake system may react to projected climate changes and how management practices can mitigate the impacts. New Hydrological Insights for the RegionThe modeling results highlight that the water quality of the lake would be closely associated with the internal hydrodynamic process driven by wind and water level operation practices as well as external nutrient loads from the upstream drainage areas. Such findings indicate that the lake and watershed management requires implementation plans and practices to be uniquely customized to efficiently improve the lake’s water quality in the future depending on the types of issues: high nutrient loads, concentrations, and algal blooms.