The Impact of Ecological Restoration Projects on the Water Quality Characteristics of Bamen Bay

This article compares the water quality characteristics of sea water in Bamen Bay to examine the effects of ecological restoration projects on the water quality of the estuary and to study the changes in the Bamen Bay estuary’s water quality characteristics before and after those projects. The findings demonstrate that, prior to the ecological restoration project, during the dry season, the DIN and P04-P content of the saltwater surpassed the second-class standards for seawater quality at a 100% excess rate, which is categorized as fourth-class seawater and is associated with eutrophic waters. While there was no excess of DIN during the ecological restoration period, there was 60% of P04-P, which was primarily dispersed towards the river mouth where it entered the sea. In Bamen Bay, eutrophication, mild potential eutrophication due to nitrogen limitation, oligotrophic conditions, and prospective eutrophication due to nitrogen limitation are all consecutively present from west to east. The excess rate of DIN and P04-P was zero following the ecological restoration project, suggesting that the water quality had reached second-class norms and belonged to oligotrophic waters. Contrarily, the ecological restoration project significantly improves the estuary’s water quality, although land-based pollution continues to be the dominant factor influencing the estuary’s water quality.