scholarly journals Evaluation of Distribution Properties of Non-Point Source Pollution in a Subtropical Monsoon Watershed by a Hydrological Model with a Modified Runoff Module

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 993 ◽  
Author(s):  
Zhou Zhang ◽  
Ping Huang ◽  
Zhonghan Chen ◽  
Junmin Li
Keyword(s):  
Point Source ◽  
Total Phosphorus ◽  
Assessment Tool ◽  
Southern China ◽  
Ammonia Nitrogen ◽  
Good Effect ◽  
Point Source Pollution ◽  
Local Pollution ◽  
Local Agriculture ◽  
Non Point Source Pollution

Non-point source pollution (NPS) is difficult to manage for watersheds, due to the scattering of pollution sources and uncertainty over the time it takes to accumulate. Since local agriculture and poultry rearing prevail, NPS occupies a large proportion of local pollution. In this paper, we modified the runoff module of the Soil and Water Assessment Tool (SWAT) to study the distribution properties and the effect of control of NPS in the Binjiang watershed in Southern China. The model was run from 2005 to 2014. The runoff simulation’s accuracy had apparently improved compared to the original model, as the Nash coefficient (Ens) had improved from 0.72 to 0.89, and the determination coefficient (R2) had improved from 0.75 to 0.91, an improvement in accuracy of 23.61% (Ens) and 21.33% (R2). Thus, the modified model (SWAT-m) is more adaptable for the simulation of extensive non-urban watersheds in subtropical monsoon climates. The validated model was used in further analysis. The results show that 82–90% of total nitrogen and 83–89% of total phosphorus were concentrated in the period from April to September annually. Through the introduction of the pollution generation potential parameter Φi, we obtained the descending order of all sub-basins in terms of their pollution generation potential. The critical source areas (CSAs) were found to be the northeast sub-basins in lower terrain that is used mainly for agricultural applications, accounting for 53% of the total watershed. The accumulation time is April to July, occupying 69% of annual generation. The simulation of management measures showed that NPS control has a good effect, with a 15 m filter strip in CSAs. Ammonia nitrogen and total phosphorus can be reduced apparently by 32% and 43%, respectively. The results may provide support for the management of NPS in watersheds under similar conditions.

The Simulation Research on Non-Point Source Pollution in Lianshui Watershed

2012 ◽  
Vol 209-211 ◽  
pp. 2018-2022
Author(s):  
Yuan Nan Long ◽  
Chang Bo Jiang ◽  
Shi Xiong Hu ◽  
Bei Chu
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Assessment Tool ◽  
Coefficient Of Determination ◽  
Dominant Factor ◽  
Nutrient Concentrations ◽  
Point Source Pollution ◽  
Time Step ◽  
Temporal And Spatial Distribution ◽  
Non Point Source Pollution

Non-point source pollution (NPSP) is an important factor that affects water quality. To study the effect of the pollution on water quality, the Soil and Water Assessment Tool (SWAT) is applied to simulate runoff and nutrient concentrations in the Lianshui Watershed. In the monthly time step, the model’s Nash-Sutcliffe coefficient and the coefficient of determination indicated that the values of simulated runoff, nutrient concentrations are acceptably closer to the measured data. Then, the study concluded that NPSP is the dominant factor affecting the water quality of the Lianshui River. Finally, the study also explored the temporal and spatial distribution characteristics of NPSP in the watershed.

scholarly journals Modelling of point and non-point source pollution of nitrate with SWAT in the river Dill, Germany

2005 ◽  
Vol 5 ◽  
pp. 7-12 ◽  
Author(s):  
T. Pohlert ◽  
J. A. Huisman ◽  
L. Breuer ◽  
H.-G. Frede
Keyword(s):  
Point Source ◽  
Assessment Tool ◽  
Future Research ◽  
Validation Period ◽  
Point Source Pollution ◽  
Calibration Period ◽  
Mountainous Catchment ◽  
Model Efficiency ◽  
Daily Discharge ◽  
Non Point Source Pollution

Abstract. We used the Soil and Water Assessment Tool (SWAT) to simulate point and non-point source pollution of nitrate in a mesoscale mountainous catchment. The results show that the model efficiency for daily discharge is 0.81 for the calibration period (November 1990 to December 1993) and 0.56 for the validation period (April 2000 to January 2003). The model efficiency for monthly nitrate load is 0.66 and 0.77 for the calibration period (April 2000 to March 2002) and validation period (April 2002 to January 2003), respectively. However, the model efficiency for daily loads is low (0.15), which cannot only be attributed to the quality of input data of point source effluents. An analysis of the internal fluxes and cycles of nitrogen pointed out considerable weaknesses in the models conceptualisation of the nitrogen modules which will be improved in future research.

Estimating Agricultural Non-Point Source Pollution in the Upper Huairou Reservoir Using the Export Coefficient Model

2013 ◽  
Vol 807-809 ◽  
pp. 1796-1799 ◽  
Author(s):  
Wei Wei Zhang ◽  
Hong Li
Keyword(s):  
Point Source ◽  
River Basin ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Scientific Basis ◽  
Point Source Pollution ◽  
Nitrogen And Phosphorus ◽  
Export Coefficient ◽  
Phosphorus Loads ◽  
Non Point Source Pollution

Quantifying agricultural non-point pollution load accurately and understanding contribution of the pollution sources clearly is the base how to control non-point source pollution effectively. Pollution loads from agricultural non-point source in the upper Lianghuai basin of Huairou Reservoir, including Huaisha River and Huaijiu River basin, were estimated according to export coefficient modeling. The results show that total nitrogen and total phosphorus loads in Lianghuai basin respectively are 322.52 t and 35.769 t in 2011.The total nitrogen and total phosphorus load intensities in Huaisha River basin are higher than that in Huaijiu River basin. Farmland planting including orchard and cropland, livestock and poultry breeding and rural domestic waste make a greater contribution to total nitrogen and total phosphorus loads. The study can provide scientific basis for further understanding characteristics of the nitrogen and phosphorus loads and agricultural structure adjustment.

scholarly journals Variation of total phosphorus concentration and loads in the upper Yangtze River and contribution of non-point sources

2021 ◽  
Author(s):  
Qian Li ◽  
Zhonghua Yang ◽  
Yao Yue ◽  
Hua Zhong ◽  
Da Li
Keyword(s):  
Point Source ◽  
Total Phosphorus ◽  
Pollution Control ◽  
Yangtze River ◽  
Point Sources ◽  
Comprehensive Treatment ◽  
Point Source Pollution ◽  
Upper Yangtze River ◽  
The Upper Yangtze River ◽  
Non Point Source Pollution

Abstract Excessive phosphorus has become the primary reason for the deterioration of the water quality of the upper Yangtze River Basin. Here, we comprehensively study variations in total phosphorus (TP) concentration and TP loads in the upper reach of the Yangtze River during 2004–2017 (after the impoundment of the Three Gorges Dam). Non-point source TP loads flowing into the mainstream are also analyzed based on the base flow segmentation method. TP concentration in the mainstream showed a fluctuating trend of decreasing–increasing–decreasing from 2004 to 2017. TP loads from tributaries had a greater impact on TP concentration in the mainstream than the retention effect. Non-point source was an important source of TP loads. Average TP loads from non-point source pollution were 24.9 × 106 kg per year, contributing about 50.8% of the TP loads from 2004 to 2017. Non-point source TP loads were mainly from Jinsha River and Jialing River, accounting for 59.1% of total non-point TP loads, and they mainly occurred in the wet season. The long-term variation trend of TP loads from tributaries was affected by economic development, intensity of pollution control and significant discharge change. In terms of pollution control, we suggest comprehensive treatment of point and non-point source pollution.

scholarly journals Spatial-Temporal Change of Land Use and Its Impact on Water Quality of East-Liao River Basin from 2000 to 2020

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1955
Author(s):  
Mingxi Zhang ◽  
Guangzhi Rong ◽  
Aru Han ◽  
Dao Riao ◽  
Xingpeng Liu ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Land Use Change ◽  
Point Source ◽  
Water Body ◽  
Forest Land ◽  
Point Source Pollution ◽  
Construction Land ◽  
Unused Land ◽  
Non Point Source Pollution

Land use change is an important driving force factor affecting the river water environment and directly affecting water quality. To analyze the impact of land use change on water quality change, this study first analyzed the land use change index of the study area. Then, the study area was divided into three subzones based on surface runoff. The relationship between the characteristics of land use change and the water quality grade was obtained by grey correlation analysis. The results showed that the land use types changed significantly in the study area since 2000, and water body and forest land were the two land types with the most significant changes. The transfer rate is cultivated field > forest land > construction land > grassland > unused land > water body. The entropy value of land use information is represented as Area I > Area III > Area II. The shift range of gravity center is forest land > grassland > water body > unused land > construction land > cultivated field. There is a strong correlation between land use change index and water quality, which can be improved and managed by changing the land use type. It is necessary to establish ecological protection areas or functional areas in Area I, artificial lawns or plantations shall be built in the river around the water body to intercept pollutants from non-point source pollution in Area II, and scientific and rational farming in the lower reaches of rivers can reduce non-point source pollution caused by farming.

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