Influence of Gate Dams on Yellow River Delta Wetlands

Abstract

Nested Delft 3D and Hydrus 1D models were applied to simulate variations in the hydrological process of tidal creeks, soil water, and salt transport in the soil profile of the reconstruction area in the Yellow River Delta under six gate dam scenarios. The results showed that the gate dam set up near the sea area was more conducive to reducing the variation range of water depth in the reconstruction area. The water depth changes in scenarios with 6 m gate valves were higher than those with 3 m sluice valves in the same gate dam location. The variations in surface water salinity, cumulative flooding time, flooding frequency, and cumulative infiltration in each scenario were similar to those for water depth. Rapid changes in soil water and salt content occurred in each scenario in periods without flooding. The fluctuation of soil salt content in different soil layers was contrary to the changes in soil water content. The overall difference in the soil salt contents and soil water content of the soil profile in scenarios with a gate dam near the sea was relatively larger than that of those with a gate dam near the shore. Obvious differences in both the soil water content and soil salt content between scenarios with 3 m and 6 m gate valves were not observed. Our results contribute to the understanding of the function of gate dams in controlling soil water and salt content in coastal wetlands.

Ecological Effects of Surface Water Evolution in the Yellow River Delta

“…In this study, the opportunity cost method was used to estimate the functional value of the surface water in the Yellow River Delta in terms of the sedimentary land reclamation, and the total income of the land after conversion was taken as the functional value of the water in terms of sedimentary land reclamation. Due to human activities such as industrial and agricultural water diversion, soil and water conservation, and water conservancy projects, the sediment discharge of the Yellow River decreased from 469 million tons in 1986 to 11 million tons in 2019 [54,55], and about 64% of the sediment in the Yellow River runoff was deposited in the estuary delta [56]. According to the total agricultural output value and cultivated land area of Dongying City, the land income per unit area was CNY 2.6 million/km 2 in 1986 and CNY 21.8 million/km 2 in 2019.…”

Morphological Characteristics and Hydrological Connectivity Evaluation of Tidal Creeks in Coastal Wetlands

“…The coastal wetlands with high hydrological connectivity are an important habitat for marine animals and salt marshes [33,34]. Since the tidal creek network is remarkably similar to the river channel network, some studies have introduced the characteristic indexes of network circuitry (α), the edge-node ratio (β), and network connectivity (γ) to assess the structural connectivity of the tidal creek network in the coastal wetlands of river deltas [35].…”