Temporal trend of sediment accumulation in the Xuan Thuy Natural Wetland Reserve (Ba Lat coastal area of the Red River) and prediction on the future coastal wetland development

Abstract

Abstract An important task for future planning and management is predicting how the coastal wetland will develop. In order to calculate the rates of sediment accumulation, five sediment cores A, B, C, D, and E were taken from the Xuan Thuy National Park. Results show that the wetland experienced two to three sedimentation periods of different sedimentation rates in the last 100 years. At the core A site, the sedimentation rate has decreased over the past 40 years from1.70 ± 0.18 to 0.77 ± 0.11 cm year‑1. For the past 20 years, the average sedimentation rates at sites B, C, D, and E have been 1.53 ± 0.18, 1.80 ± 0.32, 2.02 ± 0.22, and 2.03 ± 0.25 cm year‑1, respectively. According to the recent temporal trend of sedimentation, it is predicted that in about 35 (±10) years from now, site A will be no longer receiving sediment from the tidal creeks and will be lying above the high tidal water level. Site B, D, and E will be lying above the high tidal water level in about 75 (± 10) years. In about 80 (± 15) years, the Tra tributary riverwill be filled up with sediment and become a swamp like today site B, D and E.