Monitoring cooling water discharge using Lagrangian coherent structures: A case study in Daya Bay, China

- Using Lagrangian coherent structures (LCSs) to the study of cooling water transport.
- The LCSs delineate the pathway of the cooling water transport in coastal water.
- The LCSs can be used as a criterion to minimize the effect of coastal pollution.

As an unwanted by-product in the power plants, cooling water (CW) discharge may induce harmful effects on the coastal environment. In this paper, to accurately predict the CW transport in the Daya Bay, China, we develop a three-dimensional hydrodynamic and temperature model to simulate the transport of the CW from nuclear power plant into coastal waters. Specifically, we use the flow velocity produced by the model to locate Lagrangian coherent structures (LCSs) hidden in ocean surface currents. Result show that the transport of the CW is quite strongly tied to the simulated LCSs. The LCSs constitute fluid barriers that accurately demarcate potential pathway for CW transport. Thus, LCSs in velocity fields from a coastal model is an extremely useful way to monitor and interpret the transport of CW.