Showing papers on "Nonpoint source pollution published in 2017"

Tracking Nitrogen Sources, Transformation, and Transport at a Basin Scale with Complex Plain River Networks

Abstract: This research developed an innovative approach to reveal nitrogen sources, transformation, and transport in large and complex river networks in the Taihu Lake basin using measurement of dual stable isotopes of nitrate. The spatial patterns of δ15N corresponded to the urbanization level, and the nitrogen cycle was associated with the hydrological regime at the basin level. During the high flow season of summer, nonpoint sources from fertilizer/soils and atmospheric deposition constituted the highest proportion of the total nitrogen load. The point sources from sewage/manure, with high ammonium concentrations and high δ15N and δ18O contents in the form of nitrate, accounted for the largest inputs among all sources during the low flow season of winter. Hot spot areas with heavy point source pollution were identified, and the pollutant transport routes were revealed. Nitrification occurred widely during the warm seasons, with decreased δ18O values; whereas great potential for denitrification existed during th...

Anthropogenic Influences of Paved Runoff and Sanitary Sewage on the Dissolved Organic Matter Quality of Wet Weather Overflows: An Excitation–Emission Matrix Parallel Factor Analysis Assessment

Abstract: The quality of dissolved organic matter (DOM) in a wet weather overflow (WWF) can be broadly influenced by anthropogenic factors, such as nonpoint sources of paved runoff and point sources of sanitary sewage within the drainage networks. This study focused on the anthropogenic influences of the paved runoff and sanitary sewage on the DOM quality of WWF using excitation–emission matrix parallel factor analysis (EEM–PARAFAC). Results show that (1) EEM–PARAFAC fitted terrestrial humic-like, anthropogenic humic-like, tryptophan-like, and tyrosine-like components can be regarded as indicators to identify the types of sewage overflows and the illicit connection status of drainage systems. (2) A short emission wavelength (em: 302–313 nm) peak of the tyrosine-like component occurred in the reserved sanitary sewage, while a type of longer emission wavelength (em: 321–325 nm) peak came from the sump deposit. These tyrosine-like components were gradually evacuated in the initial phase of the overflow process with th...

Estimating Discharge and Nonpoint Source Nitrate Loading to Streams From Three End‐Member Pathways Using High‐Frequency Water Quality Data

Abstract: The myriad hydrologic and biogeochemical processes taking place in watersheds occurring across space and time are integrated and reflected in the quantity and quality of water in streams and rivers. Collection of high-frequency water quality data with sensors in surface waters provides new opportunities to disentangle these processes and quantify sources and transport of water and solutes in the coupled groundwater-surface water system. A new approach for separating the streamflow hydrograph into three components was developed and coupled with high-frequency nitrate data to estimate time-variable nitrate loads from chemically dilute quick flow, chemically concentrated quick flow, and slowflow groundwater end-member pathways for periods of up to 2 years in a groundwater-dominated and a quick-flow-dominated stream in central Wisconsin, using only streamflow and in-stream water quality data. The dilute and concentrated quick flow end-members were distinguished using high-frequency specific conductance data. Results indicate that dilute quick flow contributed less than 5% of the nitrate load at both sites, whereas 89 ± 8% of the nitrate load at the groundwater-dominated stream was from slowflow groundwater, and 84 ± 25% of the nitrate load at the quick-flow-dominated stream was from concentrated quick flow. Concentrated quick flow nitrate concentrations varied seasonally at both sites, with peak concentrations in the winter that were 2–3 times greater than minimum concentrations during the growing season. Application of this approach provides an opportunity to assess stream vulnerability to nonpoint source nitrate loading and expected stream responses to current or changing conditions and practices in watersheds.

Livestock Production and Its Impact on Nutrient Pollution and Greenhouse Gas Emissions

Abstract: The livestock sector provides more than one-third of human protein needs and is a major provider of livelihood in almost all developing countries. While providing such immense benefits to the population, poor livestock management can potentially provide harmful environmental impacts at local, regional, and national levels which have not been adequately addressed in many countries with emerging economies. Twenty-six percent of global land area is used for livestock production and forest lands are continuously being lost to such activities. Land degradation through soil erosion and nutrient depletion is very common across pastures and rangelands. The intensification of livestock production led to large surpluses of on-farm nitrogen and phosphorus inputs that can potentially contribute to nonpoint source pollution of water resources in many parts of the world. The sector is one of the largest sources of greenhouse gases (GHGs) contributing around 14.5% of all human-induced GHG emissions, a major driver of use and pollution of freshwater (accounting 10% anthropogenic water use) and a contributor to the loss of biodiversity. About 60% of global biomass harvested annually to support all human activity is consumed by livestock industry, undermining the sustainability of allocating such large resource to the industry. Despite the negative impacts of livestock production, opportunities exist to balance the competing demands of livestock production and the environment. These include (1) improved technologies and practices that increase livestock productivity with optimal use of land and water, (2) reorienting grazing systems to provide environmental services for water, biodiversity, carbon sequestration, and resource conservation, (3) reducing GHG emission from livestock production, and (4) an effective management strategy for efficient and sustainable use of manure in livestock production. Further research, appropriate policy development, and institutional support are important to ensure the competitiveness of the industry. Integration of crops with livestock production provides opportunities for increasing resource use efficiencies and reducing environmental pollution, making the system resilient to impacts of climate change, reducing GHG emissions from the system, enhancing soil quality and fertility, and improving water quantity and quality. Appropriate techniques for assessing and monitoring impacts of livestock production are necessary for developing strategies and making the system profitable, sustainable, and resilient. Isotopic and nuclear techniques play an important role in such assessment and monitoring.

Environmental Impact of Agricultural Production Activities

Abstract: The book summarizes actual and/or relative environmental impacts resulting from existing and emerging agricultural production technologies, as practised in the USA. Case studies of environmental impacts of agricultural practices are discussed in one chapter, while separate chapters consider water and soil, air quality, noise and waste impacts. Air pollutants from cultivation operations, burning, agricultural vehicles, harvesting and grain handling, pesticide applications, wind erosion etc. are all considered. Noise produced by agricultural activities and exposure patterns for agricultural workers are examined. An annotated bibliography is included for the environmental impacts discussed in the text. Emerging agricultural production technologies such as nitrogen fixation, genetic engineering, plant growth regulation, erosion control, water management and waste utilization etc. are also compared for efficiency and environmental impacts.

Contribution of Leaf Litter to Nutrient Export during Winter Months in an Urban Residential Watershed.

Abstract: Identification of nonpoint sources of nitrogen (N) and phosphorus (P) in urban systems is imperative to improving water quality and better managing eutrophication. Winter contributions and sources of annual N and P loads from urban watersheds are poorly characterized in northern cities because monitoring is often limited to warm-weather periods. To determine the winter export of N and P, we monitored stormwater outflow in a residential watershed in Saint Paul, Minnesota during 2012-2014. Our data demonstrate that winter melt events contribute a high percentage of annual N and P export (50%). We hypothesized that overwintering leaf litter that is not removed by fall street sweeping could be an important source to winter loads of N and P. We estimated contributions of this source by studying decomposition in lawns, street gutters, and catch basins during two winters. Rates of mass and N loss were negligible during both winters. However, P was quickly solubilized from decomposing leaves. Using mass balances and estimates of P leaching losses, we estimated that leaf litter could contribute 80% of winter total dissolved phosphorus (TDP) loading in this watershed (∼40% of annual TDP loading). Our work indicates that urban trees adjacent to streets likely represent a major source of P pollution in northern cities. Management that targets important winter sources such as tree leaves could be highly effective for reducing P loading and may mitigate eutrophication in urban lakes and streams in developed cities.

Evaluation of groundwater vulnerability to pollution using DRASTIC framework and GIS

Abstract: Groundwater management has a prominent role in the world especially in arid and semi-arid areas which have a shortage of water, and due to this serious problem, many researchers work on that for prevention and managing the water recourses to conserve and monitor sources. DRASTIC index can be put forward for estimating of groundwater vulnerability to such pollution. The main purpose of using the groundwater vulnerability model is to map groundwater susceptibility to pollution in different areas. However, this method has been used in various areas without modification, disregarding the effects of pollution type and characteristics. Thus, this technique must be standardized and approved for Kerman plain. Vulnerability evaluation to explain areas that are more vulnerable to contamination from anthropogenic sources has become a prominent element for land use planning and tangible resource management. This contribution aims at evaluating groundwater vulnerability by applying the DRASTIC index as well as employ sensitivity analyses to evaluate the comparative prominent of the model parameters for groundwater vulnerability in Kerman plain in the southeastern part of Iran. Moreover, the potential of vulnerability to pollution is more accurately assessed by optimizing the weights of the DRASTIC parameters with the single-parameter sensitivity analysis (SPSA). The new weights were calculated. The result of the study revealed that the DRASTIC-Sensitivity analysis exhibit more efficiently than the traditional method for a nonpoint source pollution. Observation of ultimate nitrate showed the result of DRASTIC-SPSA has more accuracy. The GIS method offers an efficient environment for carrying out assessments and greater capabilities for dealing with a huge quantity of spatial data.

Application of a land cover pollution index to model non-point pollution sources in a Brazilian watershed

Abstract: Non-point and point source pollution are a water quality problem in most parts of the World. Many studies have used the land use and land cover (LULC) to model non-point pollution sources. In this article we evaluate the relationship between LULC and five water quality parameters using different zones of analysis: riparian buffers (B) and exclusive contribution areas (ECA). The five parameters are nitrate, nitrite, total ammonia nitrogen, total phosphorous and dissolved oxygen. Analyses were performed on riparian zones of different widths and ECAs to verify if the effect of the land cover on the water quality of the stream decreases with the increased distance. The urban and agricultural/pasture categories of LULC were characterized as pollution sources while vegetation (Forest and Riparian Forest) as pollution sink (filter). We proposed a Land Cover Pollution index (LCPI) which is a ratio between source and sink to substitute the individual LULC categories. The source and sink categories were selected considering our knowledge of the LULC relationship and the sign of the Pearson's Correlation Coefficient. The LCPI varied between 0.11 in the 150 m buffer (higher filter effect) and a maximum of 27.99 (largest source effect). Additionally, we transformed the water quality data in incremental loads per unit area so that each station could be considered independent from the others and be compared between themselves independently of the contribution area they represent. Our method also included only data from the rain season, the beginning of which was determined using the hydrograms of discharge data. Results indicate that the index is better than the individual LULC classes to explain this relationship, especially in riparian zones. In 12 out of 15 models the coefficient of determination (R2) increased by 11 to 155%, when we use the index instead of the LULC classes. We believe that these good results can be attributed to the LCPI but also to the special processing of the water quality data making it more sound for statistical processing.

Water Quality Planning in Rivers: Assimilative Capacity and Dilution Flow

Abstract: Population growth, urbanization and industrial expansion are consequentially linked to increasing pollution around the world. The sources of pollution are so vast and also include point and nonpoint sources, with intrinsic challenge for control and abatement. This paper focuses on pollutant concentrations and also the distance that the pollution is in contact with the river water as objective functions to determine two main necessary characteristics for water quality management in the river. These two necessary characteristics are named assimilative capacity and dilution flow. The mean area of unacceptable concentration [Formula: see text] and affected distance (X) are considered as two objective functions to determine the dilution flow by a non-dominated sorting genetic algorithm II (NSGA-II) optimization algorithm. The results demonstrate that the variation of river flow discharge in different seasons can modify the assimilation capacity up to 97%. Moreover, when using dilution flow as a water quality management tool, results reveal that the content of [Formula: see text] and X change up to 97% and 93%, respectively.

Interactive Reservoir-Watershed Modeling Framework for Integrated Water Quality Management

Abstract: Eutrophication is a serious water pollution problem in many lakes and reservoirs. One method of understanding the causes of eutrophication and devising strategies to address this phenomenon is watershed modeling. An integrated model is developed in this paper for simulating and evaluating the water quality protection strategies of reservoirs based on controlling the upstream point and non-point sources of pollution and also reservoir operation. To achieve this, Soil and Water Assessment Tool (SWAT) model is used for modeling of the surface runoff and transportation of pollutant load over the watershed area and then, the numerical model CE-Qual-W2 is used for simulating the reservoir water quality. These models are linked to simulate the transmission and distribution of water quality variables in the Seimare watershed-reservoir system, west part of Iran. After calibration of the models, different strategies for reduction of pollution over the watershed are simulated and ranked based on their efficiency in reducing the pollution load entering into the reservoir. Results show that completion and modernization of the sewage network and wastewater treatment plant of Kermanshah city as long as adopting some measures against the direct release of municipal wastewater into the Gharehsou River can reduce the pollution load by 40–50% as the best short term strategy. It is also found that in the long-term period, watershed management and decreasing local animal husbandry activities are the most effective measure for reducing the nutrient load entering Seimare reservoir, and thus need to be considered in the future watershed management policies and programs.

Non-Point Source Nitrogen and Phosphorus Assessment and Management Plan with an Improved Method in Data-Poor Regions

Abstract: To enhance the quantitative simulation and integrated assessment of non-point source (NPS) pollution in plateau lakes in data-poor regions, a simple and practical NPS assessment method is developed by combining the improved export coefficient model (ECM) and the revised universal soil loss equation (RUSLE). This method is evaluated via application to the Chenghai Lake watershed (Yunnan Province, China), which contains a typical plateau lake. The estimated results reflect the actual situation within the watershed. The total nitrogen (TN) and total phosphorus (TP) loads in the study area in 2014 were 360.35 t/a (44.30% dissolved nitrogen (DN) and 55.70% adsorbed nitrogen (AN)) and 86.15 t/a (71.40% adsorbed phosphorus (AP)), respectively. The southern and eastern portions of the watershed are key regions for controlling dissolved and adsorbed pollutants, respectively. Soil erosion and livestock are the main TN and TP pollution sources in the study area and should be controlled first. Additionally, reasonable and practical suggestions are proposed to minimize water pollution according to a scenario analysis. The method in this study provides a foundation for scientific theories that can be used in water resources protection planning and the method can be applied to the NPS assessment of similar regions with scarce data.

Simulating water and nitrogen loss from an irrigated paddy field under continuously flooded condition with Hydrus-1D model.

Abstract: Agricultural non-point source pollution is a major factor in surface water and groundwater pollution, especially for nitrogen (N) pollution. In this paper, an experiment was conducted in a direct-seeded paddy field under traditional continuously flooded irrigation (CFI). The water movement and N transport and transformation were simulated via the Hydrus-1D model, and the model was calibrated using field measurements. The model had a total water balance error of 0.236 cm and a relative error (error/input total water) of 0.23%. For the solute transport model, the N balance error and relative error (error/input total N) were 0.36 kg ha−1 and 0.40%, respectively. The study results indicate that the plow pan plays a crucial role in vertical water movement in paddy fields. Water flow was mainly lost through surface runoff and underground drainage, with proportions to total input water of 32.33 and 42.58%, respectively. The water productivity in the study was 0.36 kg m−3. The simulated N concentration results revealed that ammonia was the main form in rice uptake (95% of total N uptake), and its concentration was much larger than for nitrate under CFI. Denitrification and volatilization were the main losses, with proportions to total consumption of 23.18 and 14.49%, respectively. Leaching (10.28%) and surface runoff loss (2.05%) were the main losses of N pushed out of the system by water. Hydrus-1D simulation was an effective method to predict water flow and N concentrations in the three different forms. The study provides results that could be used to guide water and fertilization management and field results for numerical studies of water flow and N transport and transformation in the future.

Effects of Urban Non-Point Source Pollution from Baoding City on Baiyangdian Lake, China

Abstract: Due to the high density of buildings and low quality of the drainage pipe network in the city, urban non‐point source pollution has become a serious problem encountered worldwide. This study investigated and analyzed the characteristics of non‐point source pollution in Baoding City. A simulation model for non‐point source pollution was developed based on the Stormwater Management Model (SWMM), and, the process of non‐point source pollution was simulated for Baoding City. The data was calibrated using data from two observed rainfall events (25.6 and 25.4 mm, the total rainfall on 31 July 2008 (07312008) was 25.6 mm, the total rainfall amount on 21 August 2008 (08212008) was 25.4 mm) and validated using data from an observed rainfall event (92.6 mm, the total rainfall on 08102008 was 92.6 mm) (Our monitoring data is limited by the lack of long‐term monitoring, but it can meet the requests of model calibration and validation basically). In order to analyze the effects of non‐point source pollution on Baiyangdian Lake, the characteristics and development trends of water pollution were determined using a one‐dimensional water quality model for Baoding City. The results showed that the pollutant loads for Pb, Zn, TN (Total Nitrogen), and TP (Total Phosphorus) accounted for about 30% of the total amount of pollutant load. Finally, applicable control measures for non‐point source pollution especially for Baoding were suggested, including urban rainwater and flood resources utilization and Best Management Practices (BMPs) for urban non‐point source pollution control.

Integrating Ecological Restoration of Agricultural Non-Point Source Pollution in Poyang Lake Basin in China

Abstract: This study addresses the excessive consumption of river basin water from the Poyang Lake area in China. Consumption of water for irrigation, together with the discharge of agricultural non-point source pollution, is seriously affecting the water quality of Poyang Lake. This study assesses the application of integrated ecological restoration technology for agricultural non-point source pollution in the Ganfu Plain Area, which is an important agricultural production base in the Poyang Lake basin. The results indicated that the water-fertilizer comprehensive regulation mode for double-cropping rice provided water savings of 10.4% and increased rice yield by 6.5% per hectare. Furthermore, it reduced drainage water pollution by 20.4%, and emissions of ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total phosphorus (TP), and total nitrogen (TN) from rice paddy surfaces by 18.6%, 11.1%, 15.4%, and 16.0%, respectively. The eco-channel–pond wetland system effectively reduced TN and TP pollutant levels in rice paddy drainage water; the eco-channel reduced TN and TP by 9.3% and 14.0%, respectively; and the pond wetland system showed reductions of 8.6% and 22.9%, respectively. The “three lines of defense” purification technology, including rice field source control, eco-channel interception, and pond wetland purification, removed 29.9% of TN and 44.3% of TP.

Can Water Quality Trading Fix the Agricultural Nonpoint Source Problem

Abstract: Policy analysts and government agencies promote a particular form of what they term water quality trading as a means to address the most vexing obstacle to meeting water quality standards: reducing nutrient pollutants from agricultural nonpoint sources. However, agricultural nonpoint sources’ participation in water quality trading programs will only make limited contributions to lowering overall pollutant loads. We argue that economists need to more clearly articulate the limitations of current and proposed water quality trading programs as a water quality management strategy. A new generation of market-like incentive policies will be necessary to make significant progress in reducing agricultural nonpoint source loads.

Estimation of non-point source pollution loads with flux method in Danjiangkou Reservoir area, China

Abstract: The estimation of non-point source pollution loads into the Danjiangkou Reservoir is highly significant to environmental protection in the watershed In order to overcome the drawbacks of traditional watershed numerical models, a base flow separation method was established coupled with a digital filtering method and a flux method The digital filtering method has been used to separate the base flows of the Hanjiang, Tianhe, Duhe, Danjiang, Laoguan, and Qihe rivers Based on daily discharge, base flow, and pollutant concentration data, the flux method was used to calculate the point source pollution load and non-point source pollution load The results show that: (1) In the year 2013, the total inflow of the six rivers mentioned above accounted for 959% of the total inflow to the Danjiangkou Reservoir The total pollution loads of chemical oxygen demand (COD Mn ) and total phosphorus (TP) from the six rivers were 5820 × 10 3 t and 1863 × 10 3 t, respectively, and the non-point source pollution loads were 3982 × 10 3 t and 1544 × 10 3 t, respectively, indicating that the non-point source pollution is a major factor (with a contribution rate of 684% for COD Mn and 829% for TP) (2) The Hanjiang River is the most significant contributor of pollution loads to the Danjiangkou Reservoir, and its COD Mn and TP contribution rates reached 793% and 832%, respectively The Duhe River took the second place (3) Non-point source pollution mainly occurred in the wet season in 2013, accounting for 808% and 909% of the total pollution loads of COD Mn and TP, respectively It is concluded that the emphasis of pollution control should be placed on non-point source pollution

First flush characteristics of rainfall runoff from a paddy field in the Taihu Lake watershed, China

Abstract: Nonpoint storm runoff remains a major threat to surface water quality in China. As a paddy matures, numerous fertilizers are needed, especially in the rainy seasons; the concentration of nitrogen and phosphorus in rainfall runoff from farmland is much higher than at other times, and this poses a great threat to water bodies and is the main reason for water eutrophication, especially in high concentration drainages. To date, most studies regarding the characteristics of pollutants in rainfall runoff have mainly been concentrated on urban runoff and watershed runoff; therefore, it is particularly important to investigate the characteristics of nitrogen and phosphorus loss in rainfall runoff from paddy fields. To study the characteristics of nitrogen and phosphorus loss and whether the first flush effect exists, continuous monitoring of the rainfall runoff process of six rainfall events was conducted in 2013, of which four rainfall events during storm, high, middle, and low intensity rainfalls were analyzed, and runoff and quality parameters, such as suspended solids (SS), total nitrogen (TN), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total phosphorus (TP), and phosphate (PO43--P), were analyzed to determine the relationship between runoff and water quality. The paddy field is located north of Wuxi Lake Basin along the Hejia River upstream in Zhoutie town, Yixing city. An analysis of the load distribution during rainfall runoff was conducted. Event mean concentration (EMC) was used to evaluate the pollution situation of the paddy field's rainfall runoff. A curve of the dimensionless normalized cumulative load (L) vs. normalized cumulative flow (F) (L-F curve), the probability of the mass first flush (MFFn), and the pollutants carried by the initial 25% of runoff (FF25) were used to analyze the first flush effect of the paddy field runoff, and different contaminants show different results: the concentration of nitrogen and phosphorus fluctuate and follow a similar trend as runoff changes, NO3--N concentration is lower in the early part of runoff and higher in the later, and TP mainly occurs in the particle state in storm runoff and mainly in the dissolved state when the rainfall intensity is smaller. Nitrogen and phosphorus losses from paddy fields are closely related to the average rainfall intensity and the max rainfall intensity, and the runoff loss of nitrogen and phosphorus is more severe when the rainfall intensity is large. Based on an analysis of multiple methodologies, TN and NH4+-N show a certain degree of a first flush effect, whereas the first flush effect of TP is not obvious. The first flush effect of SS is obvious in larger intensity rainfall and shows a slight secondary flush effect in smaller rainfall events.

Nutrient Assimilation Services for Water Quality Credit Trading Programs: A Comparative Analysis with Nonpoint Source Credits

Abstract: Water quality trading programs allow regulated point sources to meet some nutrient control requirements by buying nutrient reduction credits from other pollutant sources. Reduction credits can be created when agricultural land managers implement best management practices and regulators predict that those practices will result in water quality conditions equivalent to controlling discharges at the regulated source. However, natural variability in runoff combines with model and data limitations to make predictions of water quality equivalence uncertain. Nutrient assimilation credits can be created by increasing the capacity of the ecosystem to assimilate nutrients through investments in aquatic plant biomass creation and harvest, shellfish aquaculture, stream restoration, and wetlands restoration and creation. Nutrient assimilation credits and agricultural nonpoint source reduction credits are evaluated based on a number of water quality criteria including service quantification certainty, temporal ...