Characteristics Of Non-point Source Pollution Research Articles

Dynamic analysis of non-point source pollution in the Sanhekou Reservoir watershed: Implications for sustainable water management

Exogenous pollution, especially non-point source pollution runoff during a flood season, is an important factor affecting the water quality of reservoirs. The Sanhekou Reservoir (Shaanxi, China) is a newly dammed water body, so its non-point source pollution characteristics are unknown. In this study, three major tributaries of the Sanhekou Reservoir watershed were sampled during five rainfall-runoff events in the 2022 flood season. This enabled study of the transport processes of nitrogen, phosphorus, and suspended particles in the runoff under different rainfall conditions. Using hysteresis and redundancy analyses, the sources and transport modes of pollutants are explored here, alongside analysis of rainfall and hydrological characteristics that affect pollutant concentrations, and exploration of land-use relationships. The results showed that (i) nitrate nitrogen and particulate nitrogen were the main forms of nitrogen output, and particulate phosphorus was the main form of phosphorus output. (ii) Total nitrogen, suspended particles, total phosphorus, and particulate phosphorus were significantly affected by maximum rainfall intensity, average rainfall intensity, and average flow rate, whereas nitrate nitrogen and ammonia nitrogen were significantly affected by rainfall duration, rainfall amount, and rainfall-runoff duration. (iii) If 70 % of barren land and cultivated land with slope >15° were converted to forests, total nitrogen, total phosphorus, and suspended particulate loads in the Sanhekou Reservoir would be reduced during the flood season by 10.37 %, 33.01 %, and 45.39 %, respectively. The factors influencing migration and transformation of pollutants during rainfall runoff are important for operational scheduling decisions of reservoirs and guaranteeing quality of the water supply.

Spatial and temporal characteristics of non-point source pollution and risks in the drinking water source area: A case study of Heihe River in Xi’an

Climate change and human activities have posed challenges to the availability and quality of drinking water resources. In water-stressed regions of northern China, pollution in water source areas has significantly impacted public health and hindered socio-economic development. This study focuses on an important water source area in Xi’an city and utilizes high-resolution multi-source integrated remote sensing images from Google Earth and Sentinel-2 remote sensing data to interpret land use information in the water source area. The Analytic Hierarchy Process (AHP) and Non-Point Source Pollution Risks Index (NPPRI) method were employed to assess non-point source pollution risks and analyze their spatial distribution characteristics. Additionally, water quality data from 2011 to 2021 in the water source area were combined to analyze the impact of land use changes on water quality. The results indicate that most water quality indicators meet Class II standards, with total nitrogen being the main pollutant exceeding the standards, primarily originating from non-point sources such as domestic sewage, livestock, and agricultural fields within the region. The overall non-point source risk within the water source area is relatively low. The NPPRI is influenced by three factors: the proportion of non-point source risk areas within the first-level protection zone, the second-level protection zone, and the small watershed. High-risk level small watersheds are the main areas affected by non-point source pollution and should be given priority in management efforts. Therefore, based on the spatial distribution of risk factors, regional pollution prevention and control measures should be implemented to mitigate water source risks and ensure drinking water security. The research findings can provide data support for the refined management of water source area risks.

Distribution characteristics of non-point source pollution of TP and identification of key source areas in Nanyi Lake (China) Basin: based on InVEST model and source list method.

The Nanyi Lake basin, located in the middle and lower reaches of the Yangtze River, is a crucial component of the Yangtze River ecosystem. Excessive phosphorus levels lead to eutrophication in rivers and lakes. This study aims to enhance the identification efficiency of key source areas for non-point source pollution of total phosphorus (TP) in the Nanyi Lake Basin and improve decision-making regarding the treatment of these areas. The study employs the InVEST model and utilizes GIS spatial hot spot analysis to identify key source areas of agricultural TP non-point source pollution. The accuracy of the InVEST model's simulation results was verified using the source list method. The findings indicate that paddy fields serve as the primary pollution source. TP non-point source pollution in Nanyi Lake is influenced by pollution sources, pollution load filtration rate, and potential TP runoff mass concentration. Different pollution sources correspond to distinct key source areas, and the pollution generated by these sources in different administrative regions, ultimately affecting the lake, varies as well. The InVEST model demonstrates great applicability in regions where agricultural TP is the primary pollution source. For the Nanyi Lake basin, which predominantly experiences agricultural TP non-point source pollution, a combination of the InVEST model and the source list method is recommended. The InVEST model serves as the primary tool, while the source list method supplements it. This approach not only compensates for any limitations of the InVEST model's simulation results but also avoids unnecessary economic waste. The outcomes of this study contribute to a deeper scientific understanding of TP pollution in the Nanyi Lake Basin. They also aid in effectively identifying key source areas and formulating appropriate measures based on the pollution characteristics, thereby providing guidance for non-point source pollution control in the basin.

Spatial and temporal distribution characteristics and prediction analysis of nitrogen and phosphorus surface source pollution in Shandong Province under the climate and land use changes

The aim of this study was to explore the characteristics of non-point source pollution of nitrogen (N) and phosphorus (P) under the background of climate and land use in Shandong Province. First, using the InVEST NDR module in the model, N and P non-point source pollution in 2010 and 2020 in Shandong Province were simulated; then, based on precipitation data under three different global climate models (MRI-ESM-0, GFDL-ESM4, and Ec-Earth3) and two Shared Socioeconomic Pathways (SSP245 and SSP585), land use data under two Shared Socioeconomic Pathways (SSP245 and SSP585) were used to simulate and predict the non-point source pollution of N and P in Shandong Province in 2030. The results showed the following: (1) On the time scale, the output load and total output of N and P decreased during 2010–2020, while the output load and total output of N and P increased during 2020–2030. (2) On the spatial scale, the spatial distribution of N and P output loads in 2010, 2020, and 2030 is roughly the same, being “low in the northwest and high in the southeast”. (3) Different climate scenarios have a great influence on N and P output load and total output, and the N and P pollution in the SSP585 scenario is more serious. The total output of N and P did not change much in different climate models, while the spatial distribution of the output load of N and P varied significantly, indicating that different climate models had a greater impact on the spatial distribution of the output load of N and P. (4) The overall cold hot spot pattern of nitrogen and phosphorus pollution in Shandong Province is stable, basically showing a “band + cluster + scatter” distribution pattern; the hot spot area in the central and southern region of Shandong Province changes little regardless of the model, the northwest is basically a cold spot area, and the nitrogen and phosphorus hot spot area under the SSP245 scenario in Ec-Earth3 model had the least amount of change. According to research results, combined with the actual situation of Shandong Province, it is hoped that it can provide theoretical basis for the prevention and control of non-point source pollution in Shandong Province in the future.

Analysis of Spatial Distribution Characteristics of Non-Point Source Pollution in Liaoning Province

As a major agricultural province, understanding the spatial distribution characteristics of non-point source pollution in Liaoning Province plays a crucial role in preventing and controlling non-point source pollution. This paper uses the pollution discharge coefficient method to calculate the TN and TP load of non-point source pollution in each city of Liaoning Province in 2019. The results indicate that: (1) In 2019, the emissions of TN and TP from non-point source pollution in Liaoning Province were 245.6 thousand t and 23.2 thousand t, respectively. Livestock and poultry farming is the main source of TN and TP pollution. (2) The total amount of standard pollution load was 361.269 billion m3. TN is the main source of non-point source pollution, with TN and TP accounting for 67.96% and 32.04%, respectively. Overall, pollution in the central and western regions is more serious than in the eastern regions, while pollution in the plain areas is worse than in the mountainous and hilly areas. Chaoyang should be a key focus in terms of the prevention and control of non-point source pollution, and the abundant total water resources play a crucial role in reducing pollution levels.

Study on non-point source pollution characteristics under different spatial scales: a case study of Hanjiang River Basin, China.

In recent years, the research on non-point source (NPS) pollution has been deepening, but it is focused on the large-scale watershed or region. There are a few studies on the scales of small watershed and runoff plot, and it is even less to analyze the characteristics and mechanism of non-point source pollution in certain watershed by combining three different scales. Based on the combination of natural rainfall monitoring and MIKE model simulation, the Shaanxi section of Hanjiang River Basin in China was taken as an example to study the characteristics of NPS pollution at different spatial scales. The results showed that there was an obvious correlation between rainfall and runoff/sediment yield. The order of runoff yield/sediment yield per unit area was as follows: woodland > forested and grassy land > arable land. There was a significant relationship between the loss of total phosphorus and the sediment yield in the runoff plots. The total nitrogen pollution was serious, with an average concentration of 3.8mg/L. The nutrient loss was in the form of nitrate nitrogen, with an average proportion of 63.06%. For small watershed scale, the characteristics of rainfall runoff pollution generation were like runoff plot scale, both have obvious initial scour phenomenon. However, compared with runoff plot scale, the pollutant loss concentration increases with a strong lag. The MIKE model based on the coupling of hydrology, hydrodynamics, and pollution load had a strong applicability in the basin. The critical source areas of NPS pollution were identified, and five scenarios were laid out in the areas for the control of NPS pollution. Centralized livestock and poultry farming had the best reduction effect.

Characteristics of non-point source pollution based on monitoring experiment in the Yingwugou small watershed, China

Identifying the main pollutants of non-point source pollution within the scope of small watersheds, carrying out load estimation, and probing its mechanism and characteristics can provide a basis for water quality control and management. The nutrient loss characteristics, load, and reduction rate of nutrients under different land use types were analyzed through the runoff plot monitoring experiment, and the non-point source pollution load in the watershed was further calculated. Results showed that the loss of nutrients in each runoff plot was farmland>grassland>orchard in each runoff plot. Under the same slope, the loss of nutrient performance was maize>sweet potato>grassland>orchard. Taking S12 as the control group, the best reduction rate was orchard>grassland >sweet potato>maize>peanut. In runoff plot, the pollutant concentration under a single rainfall increased first and then decreased with the rainfall time. The pollutant concentrations sharply increased with the increase in flow, then gradually decreased, and finally stabilized at the outlet of the small watershed under a single rainfall. At this time, the shallow nutrients on the surface were easy to scour into the river, resulting in the sharp rise of pollutants in the river. In 2020, the losses of ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), total nitrogen (TN), orthophosphate (SRP), and total phosphorus (TP) in the basin were 41.77, 296.93, 494.51, 33.87, and 44.03 kg/km2, respectively. TN and TP were the primary nutrients in this area. The research results can provide a reference for the study of non-point source pollution in similar areas.

Is There Always a Negative Causality between Human Health and Environmental Degradation? Current Evidence from Rural China.

This study explores the incidence and trend of zoonoses in China and its relationship with environmental health and proposes suggestions for promoting the long-term sustainable development of human, animal, and environmental systems. The incidence of malaria was selected as the dependent variable, and the consumption of agricultural diesel oil and pesticides and investment in lavatory sanitation improvement in rural areas were selected as independent variables according to the characteristics of nonpoint source pollution and domestic pollution in China’s rural areas. By employing a fixed effects regression model, the results indicated that the use of pesticides was negatively associated with the incidence of malaria, continuous investment in rural toilet improvement, and an increase in economic income can play a positive role in the prevention and control of malaria incidence. Guided by the theory of One Health, this study verifies human, animal, and environmental health as a combination of mutual restriction and influence, discusses the complex causal relationship among the three, and provides evidence for sustainable development and integrated governance.

Monitoring the Landscape Pattern and Characteristics of Non-Point Source Pollution in a Mountainous River Basin.

This study aimed to assess the relationship between the landscape patterns and non-point source (NPS) pollution distribution in Qixia County, China. The sub-basin classification was conducted based on a digital elevation model and Landsat8 satellite images. Water samples were collected from each sub-basin, andtheir water quality during the wet and dry seasons was estimated. The correlation between the landscape indices and water pollution indicators was determined by Pearson analysis. The location-weighted landscape contrast index (LWLCI) was calculated based on the “source-sink” theory. Qixia was further divided into five sections based on the LWLCI score to illustrate the potential risk of NPS pollution. The results showed that the water quality in Qixia County was generally good. Cultivated land, orchards, construction areas, and unused land were positively correlated with the water pollution index and weredesignated as the “source” landscape categories, while forests, grasslands, and water bodies, which were negatively correlated with water pollution, were the “sink” landscapes; the LWCI was high in 36.94% of the study area. In these areas, measures such as increasing vegetation buffer zones are necessary to decrease the sediment and nutrient loads carried by precipitation.

Research on the non-point source pollution characteristics and water environmental capacity within small river basin of agricultural areas a case study of the small watershed near Gan village, Tanxia town

A small watershed of a tributary of the Gantang River was chosen as the study object. The water environment capacity and the amount of non-point source pollutants entering the river were calculated by combining field measurements and survey data. The results reveal that the water quality in the basin exceeds the standard severely, with 23.12t of TN, 1.64t of TP, 58t of CODMn, and 12.05t of NH3-N exceed during the plentiful period; The watershed exceeded the TN standard by 14.3t, TP by 1.64t with 17.489t of CODMn remaining in water environmental capacity and 0.71t of NH3-N exceed during the drought period. Finally, suggestions for the prevention and control of the water environment in the watershed were proposed in response to the pollution characteristics, which are of great significance for improving the water environment of the agricultural area.

Characteristics of Non-Point Source Pollution under Different Land Use Types

Non-point source pollution (NPSP) is a major challenge for current global water resources. The output characteristics of pollutants under different land use types are very important for controlling NPSP. In this study, long-term positioning monitoring and an analysis of rainfall runoff from different land use types were used to evaluate a typical watershed in the water source area of the middle route of the South-to-North Water Diversion Project (MR-SNWDP). The results show significant differences in nitrogen and phosphorus content in the runoff water bodies of various land use types. The nitrogen and phosphorus content in the MR-SNWDP was directly related to rainfall intensity and the fertilization period in the runoff following fertilization of farmland and vegetable plots. This nitrogen and phosphorus content was also observed to be significantly higher in the fertilization period than in other periods. The loss of nitrogen and phosphorus in forestland was greatly affected by rainfall intensity. Nitrogen in runoff comes primarily from farmland and vegetable fields, where its main form is nitrate nitrogen (NN). Vegetable fields are the main source of phosphorus, where its primary form is soluble phosphate (PO43−-P). Nitrogen and phosphorus have a defined incubation period during the dry season. Farmland and vegetable fields receive less rainfall during the dry season and it is difficult to form effective runoff; this allows nitrogen and phosphorus deposition. The runoff formed by the first rainfall at the beginning of the flood season (April or May) will carry a large amount of nitrogen and phosphorus from the soil into water bodies. Therefore, it is crucial to pay careful attention to the season when attempting to control NPSP.

A Comparison Study of Runoff Characteristics of Non-Point Source Pollution from Three Watersheds in South Korea

Three watersheds in Korea (Dochoncheon, Gongjicheon, Seolseongcheon) with different land cover characteristics were selected for non-point source pollution monitoring. Event mean concentration (EMC) was calculated, and runoff characteristics were compared through first-flushing and statistical analyses. The mean of the water quality parameters was the highest in Seolseongcheon during dry days among the three watersheds. EMCs of biochemical oxygen demand (BOD) and total nitrogen (TN) were higher in Dochoncheon and Gongjicheon during rainy days, respectively. The upper Seolseongchun watershed showed overall greater values of chemical oxygen demand (COD), suspended solids (SS), total organic carbon (TOC), and total phosphorus (TP). First-flush analyses indicated that SS had the strongest and TN had the weakest effects on the first flush. BOD was the highest in Dochoncheon (urban watershed) and increased with increased number of antecedent dry days. Rainfall intensity appeared to affect SS runoff strongly in Gongjicheon and Seolseongcheon. COD showed strong correlation with SS and TOC in all watersheds, and organic matter (COD and TOC) demonstrated high factor loads during dry and rainy days. Thus, organic matter–related factors were classified as the major factors in pollutant loads. TP and TN were separately classified during dry days in Gongjicheon and Seolseongcheon, whereas these were the secondary factors during rainfall when the influence of non-point pollution was substantial. Cluster analyses showed that the monitoring sites in Dochoncheon and Gongjicheon watersheds were closer than Seolseongcheon. As a result of the comparison of non-point source pollution runoff in the three watersheds, it was difficult to explain the non-point source pollution runoff by specific characteristics such as land cover. For science-based management of non-point pollution, it is necessary to obtain additional survey data considering the climatic, geographical and major industries.

Spatial distribution and output characteristics of nonpoint source pollution in the Dongjiang River basin in south China

In this research, the Dongjiang River basin was taken as the study area to analyze the spatial distribution and output characteristics of nonpoint source pollution, based on the export coefficient model. The results showed that the annual total nitrogen and phosphorus (i.e. TN and TP) loads from the Dongjiang River basin were 67916114.6 and 7215279.707 kg, respectively. Residents, forestland and pig were the main contributors for the TN load in the Dongjiang River basin, while residents, forestland and rainfed croplands were the three largest contributors for the TP load. The NPS pollution had a significant spatial variation in this area. The pollution loads overall decreased from the northeast to the southwest part of the basin. Also, the pollution loads from the gentle slope area were larger than those from steep slope areas. Among the ten tributary watersheds in the Dongjiang River basin, the TN and TP loads from the Hanxi River watershed were the largest. On the contrary, the Gongzhuang River watershed contributed least to the total pollution loads of the Dongjiang River basin. For the average pollution load intensities, Hanxi River watershed was still the largest. However, the smallest average TN and TP load intensities were in the Xinfeng River watershed.

Characteristics of non-point source pollutants on a railway bridges

The railway industry is receiving more attention these days in accordance with the high technologies being introduced into the industry. However, the research on the railway facilities has been inadequate. The interest on non-point source pollution is increasing in an effort to protect the quality of the water system. In this study, the data of the concrete road-beds on railway bridges, the runoff characteristics, event mean concentration (EMC), and pollutant load per unit area were assessed. The railway bridge concrete road-bed areas typically show the first-flush effect, whereas the railway bridge gravel road-bed areas show a two-peak effect on the runoff characteristics of non-point source pollution. The pollutant unit load and EMC in the concrete road-bed areas have also been found to be higher than those in gravel road-bed areas. The pollutant load per unit area around railway facilities shows more non-point source pollutants than other areas. The values of heavy metals and oil and grease (O&G) pollutants more washed out than heavy metals and O&G pollutants in the pavement and urban areas. The non-point source pollutants are the main type of the pollutants around the railway facilities. In order words, it is necessary to control non-point source pollution in the railway-bridge gravel road-bed areas.

Non-Point Source Pollution Control Effect Based on Comprehensive Management of Small Watershed

The urban surface runoff pollution is the most important type of urban non-point source pollution, random, wide area complex composition. The Beijing small watershed non-point source pollution comes mainly from the release of water, livestock and aquaculture, urban sewage waters, sediment release, aquatic organisms corruption farmland tail, rural solid waste and agricultural by-products pollution. Over the years these small watershed comprehensive management, significant effects of non-point source pollution control. It's mainly from non-point source pollution characteristics, hazards, main control practices begins to explain the effect of small watershed pollution in recent years, Beijing's governance, and governance prospects.

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

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.

Trapping efficiency with rainfall and seasonal changes in vegetative filter strips over a course of three years

Abstract Nonpoint source pollution does not have a clear route for elimination, and due to the amounts of these types of pollution, it is not easy to eliminate the polluting substances. In addition, the characteristics of nonpoint source pollution can easily be affected by factors other than the concentration, making it difficult to predict the pollution sources. Therefore, we installed a vegetative filter strip, which is a natural type of nonpoint source, around Kyung-An stream and calculated the trapping efficiency occurring during rainfalls, after which we analyzed these results. Over a period of 3 y, we monitored these strips 17 times, dividing the events by growth periods and non-growth periods to look more carefully into their effectiveness according to the rainfall levels. Owing to the special characteristics of nonpoint source pollution, the range of data was wider, but as we went through the elimination process, the number of outflows appeared to be more stable than the number of inflows. During ...

SWAT 모형의 유출해석모듈 개선이 수질모의에 미치는 영향

For reliable water quality simulation by semi distributed model, accurate daily runoff simulation should have preceded. In this study, newly developed channel routing method which is nonlinear storage method is combination of Muskingum routing method and variable storage routing method and temporally weighted average curve number method were applied for effect analysis of water quality simulation. Developed modules, which are added in SWAT models and simulation, were conducted for the Chungju dam watershed. The simulation result by each module applied effect. As a result of analysis contribute water quality modeling, nonlinear storage method is more effective than temporally weighted average curve number method. Nutrient loading discharge was affected by development of runoff delaying from improvement of channel routing, because of characteristics of nonpoint source pollution.

Characteristics of non-point source pollution in the watershed of Miyun Reservoir, Beijing, China

Nitrogen and phosphorus are the major nutrients to cause eutrophication to degrade water quality of the Miyun Reservoir, a very important drinking water source of Beijing, China, and they are mainly from non-point sources. The watershed in Miyun County was selected as the study region with a total area of 1400 km2. Four typical monitoring catchments and two experimental units were used to monitor the precipitation, runoff, sediment yield and pollutant loading related to various land uses in the meantime. The results show that the total nutrient loss amounts of TN and TP are 898.07 t/a, and 40.70 t/a, respectively, in which nutrients N and P carried by runoff are 91.3% and 77.3%, respectively. There is relatively heavier soil erosion in the northern mountain area whereas the main nutrient loss occurs near the northeast edge of the reservoir. Different land uses would influence the loss amounts of non-point source pollutants. The amount of nutrient loss from the agricultural land per unit is highest, that from forestry comes next and that from grassland is lowest. However, due to the variability of land use areas, agricultural land contributes a lot to TP and forestry lands to TN.

ECONOMIC INCENTIVES FOR AGRICULTURAL NONPOINT SOURCE POLLUTION CONTROL1

ABSTRACT. The limited success of command‐and‐control policies for reducing nonpoint source (NPS) water pollution mandated under the Federal Water Pollution Control Act (FWPCA) has prompted increased interest in economic incentive policies as an alternative control mechanism. A variety of measures have been proposed ranging from fairly minor modifications of existing policies to substantial revisions including watershed‐wide polices that rely on economic incentives. While greater use of economic incentive policies, such as environmental bonds and point/nonpoint source trading is being advocated in the reauthorization of the CWA, the expected effects of individual proposals will be modest. The characteristics of NPS pollution, namely uncertainty and asymmetrical information, underscores that there is no single, ideal policy instrument for controlling the many types of agricultural NPS water pollution. Some of the usual incentive‐based policies, such as effluent taxes, are not well suited to the task. Individual incentive policies proposed for the reauthorized CWA, such as pollution trading or deposit/refund systems, are not broadly applicable for heterogeneous pollution situations. Economic incentive policies may be appropriate in some cases, and command‐and‐control policies will be preferable in others and may in fact complement incentive policies.