Investigating the multi-objective oriented joint application of the channels in the Yellow River Estuary

The Yellow River Estuary channels face the challenge of balancing multiple objectives, including ensuring flood control safety, preserving ecological functions, and mitigating coastal erosion in a changing environment. This study utilizes hydrological data and field investigations to analyze the flood control situation, construction demands of the Yellow River Estuary National Park, and the condition of standby channels. The Qingshuigou channel has shown significant improvement in flood control since the implementation of sand and water regulation operations at the Xiaolangdi reservoir. However, the channel remains susceptible to large floods, which may be exacerbated by the 6‱ antislope of the current bottomland. The Qingshuigou section of the Yellow River Estuary National Park lacks downstream regulation measures following the Qing 4 river-control work, necessitating the implementation of planned scientific research platforms and infrastructure to minimize flood impacts on the main channel. The Diaokouhe section requires planned ecological water compensation of 0.055 billion m³, while the coastline suffers erosion due to insufficient sediment supply. The main channel has experienced siltation and contraction, with the bottomland facing severe encroachment from social development and construction, highlighting the urgent need for protection through regulated flow. The joint application of the channels involves normal passing flow during regular conditions, diversion of water at maximum main channel discharge, and flood release through two channels. The Diaokouhe channel accommodates a certain discharge during ordinary times and diverts a portion when the Qingshuigou channel reaches 3,500 m³/s. During large floods, the two channels serve as release passages for a flow of 5,000 m³/s.