An Integrated Methodology to Analyze the Total Nitrogen Accumulation in a Drinking Water Reservoir Based on the SWAT Model Driven by CMADS: A Case Study of the Biliuhe Reservoir in Northeast China

Abstract

Human activities, especially dam construction, have changed the nutrient cycle process at the basin scale. Reservoirs often act as a sink in the basin and more nutrients are retained due to sedimentation, which induces the eutrophication of the surface water system. This paper proposes an integrated methodology to analyze the total nitrogen (TN) accumulation in a drinking water reservoir, based on the soil and water assessment tool (SWAT) model driven by the China Meteorological Assimilation Driving Datasets for the SWAT model (CMADS). The results show that the CMADS could be applied to drive the SWAT model in Northeast China. The dynamic process of TN accumulation indicates that the distribution of TN inputted into the reservoir fluctuated with the dry and wet seasons from 2009–2016, which was mainly governed by the amount of runoff. The annual average TN input and output fluxes of the Biliuhe reservoir were 274.41 × 104 kg and 217.14 × 104 kg, which meant that 19.76% of the TN input accumulated in the reservoir. Higher TN accumulation in the reservoir did not correspond to a higher TN load, due to the influence of flood discharge and the water supply. Interestingly, a higher TN accumulation efficiency was observed in normal hydrological years, because the water source reservoir always stores most of the water input for future multiple uses but rarely discharges surplus water. The non-point sources from fertilizer and atmospheric deposition and soils constituted the highest proportion of the TN input, accounting for 35.15%, 30.15%, and 27.72% of the average input. The DBWD (Dahuofang reservoir to Biliuhe reservoir water diversion) project diverted 32.03 × 104 kg year−1 TN to the Biliuhe reservoir in 2015–2016, accounting for 14.05% of the total annual input. The discharge output and the BDWD (Biliuhe reservoir to Dalian city water diversion) project output accounted for 48.75% and 47.74%, respectively. The effects of inter-basin water diversion projects should be of great concern in drinking water source water system management. There was a rising trend of TN level in the Biliuhe reservoir, which increases the eutrophication risk of the aquatic ecosystem. The TN accumulated in the sediment contributed to a large proportion of the TN accumulated in the reservoir. In addition to decreasing the non-point source nitrogen input from the upper basin, discharging anoxic waters and sediment with a high nitrogen concentration through the bottom hole of the dam could alleviate the nitrogen pollution in the Biliuhe reservoir.

Evaluation and Analysis of Grid Precipitation Fusion Products in Jinsha River Basin Based on China Meteorological Assimilation Datasets for the SWAT Model

“…The CMADS dataset developed by Dr. Xianyong Meng provides 2008-2016 precipitation data to users free of charge and also provides scientific research support. More and more researchers are trusting this dataset and utilizing it to study complex and unique problems [49][50][51][52].…”

Moisture Distribution in Sloping Black Soil Farmland during the Freeze–Thaw Period in Northeastern China

“…We The soil temperature data of the sunny slope is more correlated with CMADS-ST, which coincides with the selection of the sunny slope in the wild slope farmland as the test Site 2. The monitored hourly data can be found in the freeze-thaw cycle with the time of day, melting during the day, and freezing at night (refer to Figure 3, the sunny slope soil experienced 39 freeze-thaw cycles, and the shady slope soil 47 cycles); however, the data period is short and the monitoring points are limited; CMADS-ST daily data can only see a large freeze-thaw cycle in the winter of the yearly cycle (refer to Figure 12); however, CMADS has a lot of spatiotemporal data, applied to a wide range of areas with a long series [11,31,33,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54].Using fixed-point monitoring of refined soil temperature, soil moisture content, precipitation, temperature, nitrogen and phosphorus of nutrients, spatiotemporal CMADS data can be better promoted and applied.…”

“…In this paper, the distribution of soil moisture in sloping black soil farmland during freeze-thaw cycles in Northeastern China is discussed. Soil moisture has great impacts on food security, human CMADS has been used successfully in different basins, such as the Heihe River Basin, Juntanghu Basin, Manas River Basin, and Han River Basin, indicating good applicability of CMADS in East Asia [38][39][40][41][42][43][44][45][46][47][48][49][50]. However, the relative studies mainly focused on the surface hydrological process and meteorological data, whereas the application of the CMADS-ST to soil temperature and soil moisture distribution has been rarely studied, especially in the black soil zone [51][52][53][54].…”

Profound Impacts of the China Meteorological Assimilation Driving Datasets for the SWAT Model (CMADS)

“…The CMADS can be used efficiently without any adjustments and treatments to the SWAT model, which will save at least 90% of the time spent by SWAT users on meteorological data preparation. From the perspective of data precision, the CMADS has been validated by users worldwide in combination with various international reanalysis data, such as Climate Forecast System Reanalysis (CFSR) and Tropical Rainfall Measuring Mission (TRMM) in various river basins in East Asia, with satisfactory results [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. These verification results demonstrate that the performance of CMADS products in East Asia can be trusted, especially in mountainous and highland areas with high altitudes and large differences of land use and geography, where meteorological stations are sparse.…”

“…This special issue provides a platform for researchers by assisting with the use of CMADS to conduct in-depth research on water quality and quantity modeling in East Asia in order to improve the research in the atmosphere, hydrology, and water environment in East Asia. The papers included in this special issue fall into eight broad categories: Meteorological verification and analysis [3,11], non-point source pollution [12], water resource modeling and parameter uncertainty analysis [13][14][15][16], comparison of reanalysis products [17][18][19][20], optimal operational of reservoirs [21,22], water footprint assessment [23], changes in water resources under climate and land use change [24], hydrological simulation in cold area [25,26], and CMADS-Soil Temperature (ST) application [27]. The following section summarizes the individual research within each application.…”