Impact of external driving forces on the nutrient transport in an artificial Seawater Lake

Abstract

Seawater lakes, with characteristics of lakes, estuaries, and oceans, face uncertainties in hydrodynamics and water quality environments due to external driving forces and nutrient transport. This study used a three-dimensional model to analyze Baisha Seawater Lake. The baroclinic model showed bottom flow velocities 2–5 times greater than the barotropic model, making it the preferred choice for such complex density-change environments. Further, external drivers (wind and runoff) significantly affected the hydrodynamics and nutrient transport of the seawater lake. Summer winds caused water circulation with flow velocity increases of 1–2 times in each layer. Runoff led to backflow zones in the surface and middle water layers of the lake. Over a one-year period, using phosphorus (P) as a nutrient indicator, we found the water quality fluctuations. Inflow water quality and the release of bed sediments were the two main factors for higher P concentrations in spring and summer. These findings are crucial for managing Baisha Lake and other similar seawater lakes, and should be considered in lake-related planning and construction.