The Yangtze River Estuary (YRE) is the largest estuary in China, with three-order bifurcations and four outlets into the sea. In recent years, issues of saltwater intrusions have received increased attention due to the increased levels and frequencies of the intrusions. The saltwater intrusions into the YRE resulting from river discharges were investigated in this study based on river discharge levels at the Datong station. A hydrodynamic and salinity transport model (MIKE21) was used to quantify the influences of the river discharges on the saltwater intrusions in the YRE. The model was effectively validated through observational data of the tidal and salinity levels. The 25%, 50% and 70% frequencies of the river discharges during the dry seasons were determined to be 18,112, 16,331 and 14,832 m 3 /s, respectively. A multi-year averaged river discharge of 27,856 m 3 /s was used to simulate the salinity level changes resulting from the different river discharges. The results revealed the following: (1) the salinity of the South Branch (SB) was distributed as "high-low-high"; and the changes in the salinity levels were greatly affected by the river discharges. A strong correlation was found between the salinity and flow in the North Branch (NB) and SB of between 0.917 and 1; (2) the changes in the river discharges had major impacts on the changes in the salinity levels in the SB. When the runoff was 27,856 m 3 /s, the salinity excessive area rate (the ratio between salinity excessive area (>0.45) and the SB area) less than 10%. However, when the river discharges were reduced to 16,331 m 3 /s, the salinity excessive area rate is more than 50%; (3) As the river discharges decreased, the amplification line (0.2) also rapidly decreased, and the amplification lines (0.45 , 2) increased. At points far from the river's entrance, the effects of the runoff were observed to be weakened, such as the amplification lines gradually becoming reduced; (4) the changes in the river discharges were observed to have significant impacts on the freshwater reservoir water withdrawal. When the river discharges were maintained at 27,856 m 3 /s, the salinity of the Baogang, Chenhang, and Qingcaosha Reservoirs remained below 0.45. The salinity levels of the four reservoir locations examined in this study were found to exceed the Chinese drinking water standard (0.45) for more than 23 days in the 14,832 m 3 /s river discharge scenario, which negatively affected the drinking water of the population living near the YRE.
Evaluating the hydrological application of reanalysis datasets is of practical importance for the design of water resources management and flood controlling facilities in regions with sparse meteorological data. This paper compared a new reanalysis dataset named CMADS with gauge observations and investigated the performance of the hydrological application of CMADS on daily streamflow, evapotranspiration, and soil moisture content simulations. The results show that: CMADS can represent meteorological elements including precipitation, temperature, relative humidity, and wind speed reasonably for both daily and monthly temporal scales while underestimates precipitation compared with gauge observations slightly (<15%). The hydrological model using CMADS dataset as meteorological inputs can capture the daily streamflow chracteristics well overall (with a NS value of 0.56 during calibration period and 0.61 during validation period) but underestimates streamflow obviously (with a BIAS of −42.42% during calibration period and a BIAS of −33.29% during validation period). The underestimation of streamflow simulated with CMADS dataset is more seriously in dry seasons (−48.40%) than that in wet seasons (−39.41%) for calibration period. The model driven by CMADS estimates evapotranspiration and soil moisture content well compared with the model driven by gauge observations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.