The water quality in Luoyuan Bay has been studied from 2004 to 2019. Eutrophication was a big issue in the spring, but there was some improvement after 2015. However, the water quality still didn't meet the standard. Nitrogen was more of a problem than phosphorus, and pollution levels were similar across the bay. Stopping aquaculture helped improve water quality. Pollution mainly came from the land after 2015. Less tidal intake due to reclamation made pollution worse at the top of the bay.