Showing papers on "Nonpoint source pollution published in 2019"
TL;DR: A simple, transparent and reliable method for evaluating non-point source pollution (NPSP) risks to drinking water source areas lacking observational data is proposed and demonstrated using a case study of the Chaihe Reservoir in northeastern China.
126 citations
TL;DR: This spatial and seasonal field study and source identification is expected to fill the data gap regarding the limited information on neonicotinoid use patterns and to inform further effective policy-making and intervention programs in China that should be urgently promoted in the near future.
Abstract: Neonicotinoid insecticides have been widely consumed worldwide, particularly in China. There is a growing interest in the environmental research community about the occurrence, fates, sources, and risks of neonicotinoids. Nine neonicotinoids in river/lake water were measured at 12 sites along the Yangtze River Basin during the dry and wet seasons in 2016, and nonpoint sources were also identified based on a modified mass balance method. A significantly higher concentration of neonicotinoids was found during the dry season probably due to the dilution effect and insecticide consumption. The high pollution levels are due to posing high ecological risks compared with the recommended thresholds. In 2016, 1190 (95% confidence interval (CI) = 822-1690) tons of neonicotinoids were transferred into the adjacent sea. Nonpoint source pollution (1700 (CI = 1200-2370) tons) was the major contributor (91.3%) to the total input of neonicotinoids into the system. Composition profiles identifying specific neonicotinoid sources indicated some changes in usage patterns from old to new types of neonicotinoids. This spatial and seasonal field study and source identification is expected to fill the data gap regarding the limited information on neonicotinoid use patterns and to inform further effective policy-making and intervention programs in China that should be urgently promoted in the near future.
77 citations
TL;DR: In this paper, the authors used boosted regression tree (BRT) and k-nearest neighbor (KNN) data mining techniques to produce a nitrate pollution vulnerability map, which can mitigate effects of subjective judgement on determining importance of different sources and mechanisms for nitrate transport.
65 citations
TL;DR: In this article, the welfare effects of cropland retirement in addressing U.S. surface water pollution problems were evaluated with a programming model of the agriculture sector and were compared to the water quality benefits from reduced soil erosion.
Abstract: Cropland retirement is one option for reducing agriculturally generated nonpoint source water pollution. This research estimated the welfare effects of cropland retirement in addressing U.S. surface water pollution problems. The social costs of retirement were evaluated with a programming model of the U.S. agriculture sector and were compared to the water quality benefits from reduced soil erosion. Results indicate that land retirement as a primary pollution control tool is expensive, but if appropriately targeted, could generate sufficient benefits to outweigh social costs. The paper also explores shifts in production patterns within and across regions caused by land retirement, and the implications for changes in chemical use and government deficiency payments. (JEL Q24)
64 citations
TL;DR: The water quality index had the highest correlation with the biotic index during the spring, implying that the lower waterquality conditions observed in the spring might be more representative of the longer-term water quality conditions in these watersheds than the higher quality conditions seen in the fall.
Abstract: The water quality in many Midwestern streams and lakes is negatively impacted by agricultural activities. Although the agricultural inputs that degrade water quality are well known, the impact of these inputs varies as a function of geologic and topographic parameters. To better understand how a range of land use, geologic, and topographic factors affect water quality in Midwestern watersheds, we sampled surface water quality parameters, including nitrate, phosphate, dissolved oxygen, turbidity, bacteria, pH, specific conductance, temperature, and biotic index (BI) in 35 independent sub-watersheds within the Lower Grand River Watershed in northern Missouri. For each sub-watershed, the land use/land cover, soil texture, depth to bedrock, depth to the water table, recent precipitation area, total stream length, watershed shape/relief ratio, topographic complexity, mean elevation, and slope were determined. Water quality sampling was conducted twice: in the spring and in the late summer/early fall. A pairwise comparison of water quality parameters acquired in the fall and spring showed that each of these factors varies considerably with season, suggesting that the timing is critical when comparing water quality indicators. Correlation analysis between water quality indicators and watershed characteristics revealed that both geologic and land use characteristics correlated significantly with water quality parameters. The water quality index had the highest correlation with the biotic index during the spring, implying that the lower water quality conditions observed in the spring might be more representative of the longer-term water quality conditions in these watersheds than the higher quality conditions observed in the fall. An assessment of macroinvertebrates indicated that the biotic index was primarily influenced by nutrient loading due to excessive amounts of phosphorus (P) and nitrogen (N) discharge from agricultural land uses. The PCA analysis found a correlation between turbidity, E. coli, and BI, suggesting that livestock grazing may adversely affect the water quality in this watershed. Moreover, this analysis found that N, P, and SC contribute greatly to the observed water quality variability. The results of this study can be used to improve decision-making strategies to improve water quality for the entire river basin.
57 citations
TL;DR: The results show that landscape pattern significantly affects river water quality, and this effect was quite different in dry and rainy seasons.
57 citations
TL;DR: Geochemical baseline can be used not only to determine the enrichment degree but also as a potentially useful tool for identifying the pollution source (local and non-point source) of heavy metals in sediments.
49 citations
TL;DR: In this paper, a novel optimization methodology was developed, utilizing a BMP database that includes BMP reduction efficiencies and costs, using a multi-objective sorting genetic algorithm (NSGA-II, nondominated sorting GA-II) combined with the Soil Water and Assessment Tool (SWAT) served as the watershed model.
46 citations
TL;DR: In this article, a study was conducted in a small independent agroforestry watershed in subtropical hilly terrain of China, where surface runoff was measured from cropland, tea garden, citrus orchard, and natural woodland on a slope area.
42 citations
TL;DR: The estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model and showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an “inflection point” between the irrigation water amount and field drainage amount.
Abstract: It is the key point to reveal the effect of irrigation water and fertilization conditions on the agriculture non-point pollution in the paddy field. In this study, the estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model. Based on the estimation model of agricultural non-point source pollution in the field and experimental data, the load of agricultural non-point source pollution in different irrigate amount and fertilization schedule in paddy field was calculated. The results showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an “inflection point” between the irrigation water amount and field drainage amount. The non-point pollution load increased with the increase of irrigation water and showed a significant power correlation. Under the different irrigation condition, the increase amplitude of non-point pollution load with the increase of irrigation water was different. When the irrigation water is smaller, the non-point pollution load increase relatively less, and when the irrigation water increased to inflection point, the non-point pollution load will increase considerably. In addition, there was a positive correlation between the fertilization and non-point pollution load. The non-point pollution load had obvious difference in different fertilization schedule even with same fertilization level, in which the fertilizer pollution load increased the most in the period of turning green to tillering. The results provide some basis for the field control and management of agricultural non-point source pollution.
41 citations
TL;DR: In this article, the experimental choice method was used to empirically analyze policy preferences during the process of fertilizer reduction, and the results indicated that households show different preferences for the three policy settings: the fertilizer application rate is reduced by 6.98% if providing full technological guidance for farmers throughout the wheat planting process and is reduced further by 5.18% under the background of providing appropriate organic fertilizer subsidies.
Abstract: This paper takes 516 households who planted wheat in Heyang County, Shaanxi Province in 2018, as samples to construct three policy environments: Technological guidance for planting, subsidies for organic fertilizer application, and agricultural tailwater discharge standards. The experimental choice method was used to empirically analyze policy preferences during the process of fertilizer reduction. The results indicate that households show different preferences for the three policy settings: The fertilizer application rate is reduced by 6.98% if providing full technological guidance for farmers throughout the wheat planting process and is reduced by 5.18% under the background of providing appropriate organic fertilizer subsidies. The agricultural tailwater discharge standards have the least impact on the reducing level of chemical fertilizer application, with decreasing amounts of only 1.85% and 0.77% under the second-level and the first-level agricultural tailwater discharge standards, respectively. These results indicate that households in Heyang County, Shaanxi Province, demonstrate a low willingness to accept the agricultural tailwater discharge standards in order to cut down on the amount of chemical fertilizer application and the agricultural non-point source pollution. Therefore, compared with a compounded annual growth rate (CAGR) of 1% of fertilizer usage nationwide according to the Chinese Ministry of Agriculture, given the current planting environment and policies design, providing comprehensive technological guidance as well as price subsidies for the organic fertilizer can significantly and robustly reduce the excessive application of fertilizer in Heyang County, Shaanxi Province, under the best scenario, thereby further alleviating agricultural non-point source pollution.
TL;DR: In this article, a multi-scale model framework and indices were developed as a decision support platform for solving the impact of spatial scale change on the optimization of best management measures in the Chaohe River Watershed in Beijing and Hebei province.
TL;DR: It is suggested that reducing number of farms and extending the length of farm property rights can benefit the mitigation of agricultural non-point pollution in China.
Abstract: Agricultural non-point source pollution causes global warming and the deterioration of air and water quality. It is difficult to identify and monitor the emission sources of agricultural pollution due to the large number of farms in China. Many studies focus on the technological aspect of achieving agricultural sustainability, but its socioeconomic aspect is poorly understood. Here, we report how group size (number of farms in a certain region) affects agricultural pollution governance through conducting a social science experiment. We found that when communication was allowed among group members, a small group size facilitated cooperation. Although deviations from the cooperation equilibrium occurred with time in all groups, the smaller the group size, the slower the cooperation equilibrium became frangible. These findings suggest that reducing number of farms and extending the length of farm property rights can benefit the mitigation of agricultural non-point pollution in China. Social science experiments can be a useful tool to understand the socioeconomic aspect of agricultural sustainability.
TL;DR: In this article, a watershed model was applied to long-term high-resolution monitoring data, and to evaluate the reduction of nonpoint-source pollution by implementing best management practices (BMPs) in a small agricultural watershed located in southwestern Japan.
TL;DR: In this paper, an export coefficient approach (ECA) and the Soil and Water Assessment Tool (SWAT) were implemented to identify the agricultural nonpoint source pollution and its associated quantitative contributions in the Three Gorges Reservoir Region, China.
TL;DR: In this article, the authors presented an approach for an increased understanding of NPS pollution characteristics and controls during events (intra-event) and between events (inter-event), by combining monitoring, modeling, and multivariate statistics.
Abstract: Rainfall-runoff events can account for transferring a significant portion of agricultural nonpoint source (NPS) pollution loads to surface water bodies. Nevertheless, mechanistic understanding of intra- and inter-event characteristics and underlying controls are not sufficiently obtained especially under conditions of scarce monitoring data, which hampers the design of appropriate management strategies. This paper presented an approach for an increased understanding of NPS pollution characteristics and controls during events (intra-event) and between events (inter-event) by combining monitoring, modeling, and multivariate statistics. Event-based NPS modeling by the Hydrological Simulation Program-Fortran (HSPF) model was improved of its predictive ability by incorporating intra-event variability based on grab samplings during representative rainfall-runoff events. The validated model was then used to simulate the intra- and inter-event dynamics of flow, suspended sediment, total phosphorus (TP), and total nitrogen (TN) exports in 100 rainfall-runoff events with different event types. The simulation results suggested that the intra-event distribution (e.g., dispersion degree and maximum changing rate) varied between event types. A higher level of event types generally resulted in more sensitive and flashy catchment responses to rainfall-runoff events, while nutrient availability from fertilizer application, antecedent soil moisture, and precipitation intensity also drove the intra- and inter-event patterns. Load duration curves and flow-weighted concentrations showed that the TN pollution in the study area was extremely severe, especially for the high flow regime and V-E heavy (i.e. very heavy and extremely heavy) events which should be paid particular attention in designing vegetation- and storage-based conservation practices. The principal component analysis revealed that controlling factors varied among event types. Sediment and TP exports were transport-limited in medium and heavy events; TN export was transport-, pre-condition-, and source-limited in medium, heavy, and V-E heavy events, respectively. The combined framework offers insights into agricultural NPS pollution controls from an event-based prospective.
TL;DR: Perturbation analysis revealed that global warming has a more significant effect on chlorophyll a levels than on total phosphorus or total nitrogen in the lake area, and that external nutrient loading is a key factor aggravating eutrophication.
TL;DR: A multi-objective evaluation model is established based on the analytical hierarchy process (AHP) combined with grey relational analysis (GRA) to identify the optimal scheme considering six indices, namely, pollutant reductions, and costs (construction and operational costs).
TL;DR: In this article, the authors quantify the impacts of climate change on watershed hydrological processes and water quality, evaluate the efficiency of Best Management Practices (BMPs) and the possible effects of a changing climate, and configure cost-effective BMPs at sub-basin scale using a multi-objective optimization method to mitigate climate effects on water resource.
TL;DR: Wang et al. as discussed by the authors conducted a systemic review of the literature related to SWAT model application and found that the research hotspots of SWAT model include water quality problem, sediment yield, model calibration, uncertainty analysis and sensitivity analysis.
Abstract: Wang, Y.; Jiang, R.; Xie, J.; Zhao, Y.; Yan, D., and Yang, S., 2019. Soil and water assessment tool (SWAT) model: A systemic review. In: Guido-Aldana, P.A. and Mulahasan, S. (eds.), Advances in Water Resources and Exploration. Journal of Coastal Research, Special Issue No. 93, pp. 22–30. Coconut Creek (Florida), ISSN 0749-0208.Under the influences of climate change and human activities, the water cycle under changing environment and distributed hydrological model based on physical mechanism have become the focus of hydrology research. Soil & Water Assessment Tool (SWAT) model is one of typical distributed models, and it has been widely used in testing and forecasting the water and sediment circulation and agriculture production with chemicals. The paper used CiteSpace to analyze the research progress based on previous literatures. The results of high frequency keywords and co-word analysis show that the research hotspots of SWAT model include water quality problem, sediment yield, model calibration, uncertainty analysis and sensitivity analysis. The literatures related to SWAT were divided into model application, model accuracy and model coupling. The paper mainly focused on the literature related to model application. The domestic and abroad research processes were reviewed from three hot application fields such as runoff simulation, hydrological impacts under changing environment (HIUCE) and non-point source (NPS) pollution. The results show that: (1) the research content of runoff simulation mainly focused on the adaptability and accuracy of the model; (2) the research content of HIUCE mainly concentrated on analysis of historical changes in hydrological effects and prediction of future changes using the scenario analysis; (3) the research content of NPS pollution mainly focused on the spatial and temporal distribution of nutrients, the influencing factors and degree of nutrients, and the prediction of future to select Best Management Practices (BMPs). The paper pointed out some existing problems, prospected the future research, and proposed research idea of model improvement to adapt to the domestic changing environment. This study should be beneficial to systematically understand the structure, principle, application fields and future development trends of SWAT model, and thus provide references for users of SWAT model in related subjects.
22 Jan 2019
TL;DR: In this paper, the authors provide a survey of up-to-date technologies for remediation, as well as a step-by-step guide to pollution assessment for both ground and surface waters.
Abstract: This book contains almost all the technical know-how that is required to clean up the water supply. It provides a survey of up-to-date technologies for remediation, as well as a step-by-step guide to pollution assessment for both ground and surface waters. In addition to focusing on causes, effects, and remedies, the book stresses reuse, recycling, and recovery of resources. The authors suggest that through total recycling wastes can become resources.
TL;DR: In this paper, the authors investigated the impact of various BMPs in reducing sediment and phosphorus loading rates on various spatial and temporal scales in the watershed using SWAT for the years 2001-2010.
TL;DR: It is revealed that no single BMP could achieve the water quality improvement targets and the importance of optimal configuration of BMP combinations at sub-basin scale is highlighted.
Abstract: Non-point source (NPS) pollution, including fertilizer and manure application, sediment erosion, and haphazard discharge of wastewater, has led to a wide range of water pollution problems in the Miyun Reservoir, the most important drinking water source in Beijing. In this study, the Soil and Water Assessment Tool (SWAT) model was used to evaluate NPS pollution loads and the effectiveness of best management practices (BMPs) in the two subwatersheds within the Miyun Reservoir Watershed (MRW). Spatial distributions of soil types and land uses, and changes in precipitation and fertilizer application, were analysed to elucidate the distribution of pollution in this watershed from 1990 to 2010. The results demonstrated that the nutrient losses were significantly affected by soil properties and higher in both agricultural land and barren land. The temporal distribution of pollutant loads was consistent with that of precipitation. Soil erosion and nutrient losses would increase risks of water eutrophication and ecosystem degradation in the Miyun Reservoir. The well-calibrated SWAT model was used to assess the effects of several Best Management Practices (BMPs), including filter strips, grassed waterways, constructed wetlands, detention basins, converting farmland to forest, soil nutrient management, conservation tillage, contour farming, and strip cropping. The removal rates of those BMPs ranged from 1.03 to 38.40% and from 1.36 to 39.34% for total nitrogen (TN) and total phosphorus (TP) loads, respectively. The efficiency of BMPs was dependent on design parameters and local factors and varied in different sub-basins. This study revealed that no single BMP could achieve the water quality improvement targets and highlighted the importance of optimal configuration of BMP combinations at sub-basin scale. The findings presented here provide valuable information for developing the sustainable watershed management strategies.
TL;DR: Arauzo et al. as discussed by the authors determined the groundwater quality and vulnerability to pollution in west Luxor Governorate, Egypt using 50 boreholes sampled during October 2014 and groundwater samples were analyzed chemically.
TL;DR: In this paper, an integrated method was developed for separating baseflow and surface NPS pollutants at the watershed scale, and the uncertainty of the prediction of baseflow NPS pollution was explored by comparing four hydrographic separation methods (the United Kingdom Institute of Hydrology (UKIH), the Lyne-Hollick (LH) method, the Eckhardt (ECK) method and the Soil and Water Assessment Tool (SWAT)), three data sources (monitoring data, SWAT and the LOADEST model) and two baseflow period assumptions.
TL;DR: A new prediction model of pollution risks by combing pollutant sources, precipitation, and landscape structure, which was defined as the source-precipitation-landscape model (SPLM), was applied to simulate the non-point source (NPS) total nitrogen (TN) exports in one of the largest river basins in China.
Abstract: Traditional models of nutrient simulation usually focus on the pollutant sources and precipitation, lacking the quantification of landscape structure. We developed a new prediction model of pollution risks by combing pollutant sources, precipitation, and landscape structure, which was defined as the source-precipitation-landscape model (SPLM). The SPLM was applied to simulate the non-point source (NPS) total nitrogen (TN) exports in one of the largest river basins in China (the Haihe River Basin, HRB). TN concentrations of 35 sampling catchments in 2013 were used to test the accuracy of the SPLM. Simulated results showed that (1) the SPLM had a relative high accuracy in the simulation of NPS TN export and intensity, especially for TN intensity. (2) The mean TN export and intensity of all the 1578 catchments in the HRB were 441.97 t and 2.08 t/km2, respectively. (3) The TN export intensities differed greatly among the sub-basins in the HRB, ranging from 0.64 to 6.81 t/km2. On the whole, the TN export intensities of the plain sub-basins (e.g., the Tuhaimajia River, the Heilonggang River, and the Beisihe River) were much higher than those of mountainous sub-basins (e.g., the Yongding River, the Beisanhe River, and the Luanhe River). (4) The contributions to TN exports, from high to low, were land use (38.82%), livestock husbandry (33.57%), and rural population (27.61%). Among all the ten pollution sources, arable land (30.87%), rural population (27.61%), and large livestock (17.73%) had the top three contributions to TN exports. This study provides a feasible tool for policymakers and administrators to develop workable management measures for the mitigation of NPS pollution. This SPLM can be extended to other regions in a rapid urbanization context.
TL;DR: Optimal performances for pollutant purification and operation parameters were achieved in different water seasons and appropriate hydraulic loading rate and mass loading rate would give better purification performances in wet season.
TL;DR: The results showed that the first flush strength was reduced after setting low impact development (LID) implementation in the community, and ammonia nitrogen and phosphorus were the main pollutants in the firstflush in the study area.
Abstract: To study the first flush effect of nonpoint source pollution in the Guangzhou community unit, runoff from roads, roofs, and green spaces during three rainfall events was collected and analyzed for pollutants. Nine runoff pollution indices were considered. The dimensionless cumulative curve of pollutant mass vs. volume, the first flush coefficient (b) and the mass first flush ratio (MFFn) were used to assess the first flush effect of different underlying surfaces. The assessment results pointed out that the roof was most prone to first flush effect. And ammonia nitrogen and phosphorus were the main pollutants in the first flush in the study area. For a quantitative analysis of the first flush, the Storm Water Management Model (SWMM) was used to simulate the hydrological effect of low impact development (LID) implementation in the community. The results showed that the first flush strength was reduced after setting LID. And LID measures, such as green roofs and sunken green spaces, contribute to flood control and rainwater purification. This research can be relevant regarding for constructing sponge cities and reducing the pollution caused by the first flush.
TL;DR: An assessment of the twelve Mississippi River states' Nutrient Reduction Strategies finds that the use of best science is limited, the role of livestock in pollution and its abatement is ignored, and the development of Numeric Nutrient Criteria is stalled.