Analysis of temporal and spatial changes of the Laoshan Bay shoreline and discussion on ecological restoration

Laoshan Bay is an important base for building a maritime power in Qingdao, Shandong Province. Four high-resolution remote sensing images of Laoshan Bay from 2005 to 2020 were selected, the temporal-spatial changes of the coastline in Laoshan Bay was analyzed using the Digital Shoreline Analysis System (DSAS) in consideration of local social and economic development, the driving forces of coastline evolution was determined, and future ecological restoration of the coastal zone was proposed. Results show that between 2005 and 2020, the overall length of the Laoshan Bay coastline increased by 6.75 km, the area within the bay decreased by 18.01 km², the natural coastline decreased by 3.41 km, and the artificial coastline increased by 10.16 km and kept increasing. From 2005 to 2010, the coast of Laoshan Bay was in a slow erosion state. After 2010, the coast of Laoshan Bay was in a growth state, due mainly to reclamation and coastal engineering construction north of Aoshantou. After 2015, with the gradual improvement of coastal engineering construction and the implementation of the urban blue bay strategy, the growth rate of the coastline was relatively small. The factors such as reclamation and cultivation for fishery development, land reclamation for urban construction, and coastal engineering construction are the main driving factors for the change of the coastline in Laoshan Bay. In view of the current situation of coastline changes in Laoshan Bay, it is recommended to integrate engineering with vegetation ecological restoration to effectively promote ecological protection and sustainable development of the coastal zone of Laoshan Bay.