Investigating the impact of Xuanmen Project on water residence time in the Yueqing Bay

Abstract

Abstract A 2D numerical model was used to investigate the impact of Xuanmen Project on water residence time in Yueqing Bay. Three model scenarios were designed to calculate the residence time. The WRT of CASE00 was obviously smaller than that of CASE01 and CASE02. While the WRT of CASE01 and CASE02 was relatively comparable. As for the individual scenario, the WRT increased from the bay month to the bay head. In CASE00, The average WRT of the outer bay, middle bay and inner bay was 21.6, 38.5 and 50.6 days, respectively. The average WRT of the entire bay was 32.7 days. In CASE01, a significant increase of WRT was observed in the entire bay. The average WRT of the entire bay was 46.1 days. The WRT increased about 10 days in the lower bay and 20 days in the northern bay compared to CASE00, indicating a significant impact of the Xuanmen Dam. In CASE02, the average WRT of the entire bay was 48.2 days. The WRT increased less than 5 days compared to CASE01, implying that the land reclamation had a minor impact on the WRT of the Yueqing bay. The flushing homogeneity curve (FHC) was used to study the spatial characteristic of flushing. The steepest curve occurred in CASE00 and the flattest curve occurred in CASE02, implying an increased inhomogeneity due to Xuanmen Project.