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The goal of environmental management in China is transitioning from pollution control to the improvement of ecological quality. The establishment of regional differential water quality standards can better adapt to the ecological characteristics and development needs of different regions. Given the shortcomings of current water quality standards and the needs of technological development, this study analyzed the causes and influencing factors of regional differences in water quality standards and summarized China's regional variations in areas such as the characteristics of receiving water bodies, social attributes, climate conditions, physicochemical properties of water, and aquatic biotic populations. It also examined the impact of regional characteristics on the assessment of biological toxicity. Based on these analyses, the study identified key scientific questions that may arise in the development of regional differential water quality standards in China and outlined future critical research directions in this field. These directions include developing theories and methods for determining the effluent dilution coefficient, establishing methods for identifying regional key water quality indicators and assessing their impact on water quality standards, determining regional characteristic species and their influence on water quality standards, and formulating theories and methods for categorizing different regions across the country. The aim of the study was to provide a reference for the scientific establishment of water quality standards in China.

Public participation is crucial to improving the performance of water governance systems, especially in a governance model dominated by a top-down hierarchical structure. Public concerns, as a vital form of public participation, have been acknowledged as an essential component in contributing to water governance. However, few studies explore the varying effects of diverse public concerns in leading to different water governance outcomes. This study addresses this gap by exploring the direct and indirect effects of water-related public concerns on water pollution control and governments' pollution mitigating actions, using citizens' water-related posts crawled from China's social media. Results show that public water-related concerns contribute to water governance both through its direct effects on reducing water pollution and indirect effects by promoting policy actions. Specifically, the concerns related to water pollution hazards, water pollution monitoring, prevention products, and water pollution control measures have more positive impacts on water pollution reduction compared to other types of concern. Meanwhile, public concerns demonstrate stronger effects in triggering economic-related and infrastructure-related water pollution mitigation actions. This study provides nuanced insights to understand the role of public participation in improving water governance, the findings of which are insightful to enhance accountability of water governance systems through a bottom-up approach., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Ship transportation is a primary mode for global trade and cargo transport, yet even minor discrepancies can lead to ship accidents, causing severe secondary environmental pollution. Maritime accidents involve complex and numerous factors. Formal Concept Analysis (FCA) can identify the key contributing factors and their impact levels by eliminating homogenization factors in maritime accidents. This study constructs an innovative FCA model of ship accidents in Chinese waters, utilizing 172 ship accident reports released by the China Maritime Safety Administration. The analysis reveals seven reduced sets and 23 diagnostic rules of ship accidents. Results show that failed ship registration/security inspection, deficient nautical data and instruments, and management issues are the most critical factors. Three accident chains are identified and corresponding mitigation strategies are proposed to reduce potential pollution from ship accidents. These strategies offer significant reference value for preventing ship accidents and reducing their environmental impact in China and globally., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

This study designs a double-bounded dichotomous questionnaire, and uses the Contingent Valuation Method (CVM) to estimate residents' willingness to pay(WTP) for water pollution control along the Taihu Lake Basin. The results of the returned questionnaire show that 82.76% of the residents are willing to pay. CVM estimation results show that the average WTP of residents for water pollution control is 138.86 yuan/year. In addition, the influencing factors of WTP are explored using a Logistic regression model, and the heterogeneity of WTP among residents of different genders is analyzed. The study found that: (1) The younger the residents, the higher their WTP; (2) The higher the income, the higher the residents' WTP for water pollution control; (3) Residents with higher educational level are more willing to pay; (4) The higher the degree of residents' understanding of water pollution control policies, the higher the WTP; (5) The higher the degree of residents' recognition of pro-environmental behavior, the higher the WTP; (6) Male residents' WTP is mainly affected by cognitive factors such as their understanding of governance policies and their approval of pro-environmental behaviors, while female residents' WTP is mainly affected by personal attributes, such as age, income, and the number of household laborers. Furthermore, this study proposes targeted measures to improve residents' WTP from three aspects: the government enriches the channels for residents to participate in water pollution control, the social media enriches the popularization of water environment knowledge, and the school strengthens the education of environmental protection knowledge, considering the differences in residents' characteristics. Therefore, this study can provide a theoretical reference and decision-making basis for encouraging residents to participate in water pollution control, promote the construction of a beautiful watershed, and provide a reference for other basins., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Water resource management, as a foundation for supporting sustainable urban development, has garnered increasing attention from scholars. Developing effective water resource management plans is a major challenge faced by countries worldwide. This study uses the 2015 Water Pollution Control and Prevention Action Plan (WPCAP) in China as a natural experiment and employs a Difference-in-Differences (DID) model to estimate the relationship between WPCAP and urban water pollution from 2010 to 2021. The findings are as follows: 1) WPCAP reduces water pollution. 2) WPCAP decreases water pollution in high-policy-pressure cities but increases water pollution in low-policy-pressure cities within a 60 km radius, particularly having a significantly negative impact on water pollution in low-policy-pressure cities with low altitude. 3) optimizing industrial and domestic water use, as well as enhancing sewage treatment capabilities, are crucial pathways through which WPCAP reduces water pollution. Additionally, WPCAP significantly improves water pollution control capabilities in cities with abundant water resources, large cities, and industrialized cities. 4) although WPCAP's ability to control water pollution increases management costs, it also raises residential income and promotes population growth. These findings have important implications for the sustainable development of water resources in emerging countries, including China., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With rapid economic growth, the issue of water pollution has become increasingly prominent, and there is a consensus that river basin management systems and cross-regional management coordination mechanisms need improving. In this study, 171 transboundary sections of the Yangtze River Basin were matched with the data of 57 cities to construct panel data from 2015 to 2021. Based on the four-dimensional framework of environment-determination-process-resources, the dynamic qualitative comparative analysis (QCA) method is used to identify the key influencing factors and action paths of water pollution collaborative governance effects. The results show that a single antecedent condition is not necessary to achieve efficient collaborative governance effects, and only the "number of collaborative governance" and "scale of collaboration" conditions played important roles. There are five paths that can achieve efficient collaborative governance effects: economy-oriented, ecology-oriented, technology-oriented, government-oriented, and all-oriented. Additionally, heterogeneous results show that the impact of the regional governance intention on efficient collaborative governance effect is limited in the middle and upstream sections of the Yangtze River Basin, while the downstream sections are more dependent on the basic condition of the basin. The results can help promote effective cross-regional collaboration in the Yangtze River Basin, provide scientific basis for regions to formulate targeted governance measures, and provide models for governance in other regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Water diversion projects have proven to be effective interventions to improve water quality in irrigation ditches. This study focused on quantifying the water quality improvement by utilizing a hydrodynamic water quality model in Funing County, Yancheng City. The model performed a spatial analysis of pollution concentrations across the study area. Various optimization scenarios were designed based on the diversion project and hydrological structure connectivity. The model was used to simulate changes in nutrient concentrations under different scenarios. The findings of this study were as follows: (1) Rural areas had lower nutrient concentrations and superior hydrological connectivity than urban areas. (2) The effect of water quality improvement correlated positively with increased flow rates introduced by the diversion project. Specifically, when the flow rate increased by 50%, the average reductions were 20% for NH 4 + , 5.2% for TN, and 5.1% for TP. Furthermore, introduced clean water led to more pronounced improvements in the overall regional water quality. (3) Although increasing the number of ditches improved water pollution concentration, the impact was not significant. (4) Model simulation results showed that 18 to 45% water diversion intensity effectively improved water quality, and the optimal water diversion intensity was 27 to 30%. The optimal water diversion intensities offered valuable insights for managing this region. The study's methods contributed to the promotion of sustainable development in regional water resources and the integrated management of the water environment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Accurately obtaining the pollution sources and their contribution rates is the basis for refining watershed management. Although many source analysis methods have been proposed, a systematic framework for watershed management is still lacking, including the complete process of pollution source identification to control. We proposed a framework for identification and abatement of pollutants and applied in the Huangshui River Basin. A newer contaminant flux variation method based on a one-dimensional river water quality model was used to calculate the contribution of pollutants. The contributions of various factors to the over-standard parameters of water quality sections at different spatial and temporal scales were calculated. Based on the calculation results, corresponding pollution abatement projects were developed, and the effectiveness of the projects was evaluated through scenario simulation. Our results showed that the large scale livestock and poultry farms and sewage treatment plants were the largest sources of total nitrogen (TP) in Xiaoxia bridge section, with contribution rates of 46.02% and 36.74%, respectively. Additionally, the largest contribution sources of ammonia nitrogen (NH 3 -N) were sewage treatment plants (36.17%) and industrial sewage (26.33%). Three towns that contributed the most to TP were Lejiawan Town (14.4%), Ganhetan Town (7.3%) and Handong Hui Nationality town (6.6%), while NH 3 -N mainly from the Lejiawan Town (15.9%), Xinghai Road Sub-district (12.4%) and Mafang Sub-district (9.5%). Further analysis found that point sources in these towns were the main contributor to TP and NH 3 -N. Accordingly, we developed abatement projects for point sources. Scenario simulation indicated that the TP and NH 3 -N could be significantly improved by closing down and upgrading relevant sewage treatment plants and building facilities for large scale livestock and poultry farms. The framework adopted in this study can accurately identify pollution sources and evaluate the effectiveness of pollution abatement projects, which is conducive to the refined water environment management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The innovative environmental system known as the river chief system (RCS) was developed in China to limit water pollution by appointing provincial, prefectural, county, and township officials as "river chiefs" as guardians of every river under their control. Our research project developed a quasi-natural experiment to investigate if the RCS effectively reduces the intensity of industrial water pollution. A multi-period difference-in-difference (DID) method was employed in the experiment with a total of 3808 samples from 272 prefecture-level cities. The samples gathered represented the years from 2007 to 2020. Our results demonstrated that the southern region has far more industrial water contamination than other locations, and the intensity of industrial sewage discharge decreased by 10.25% in pilot cities following the implementation of the RCS compared with what we observed in non-pilot cities. Furthermore, according to the mechanism analysis we used, cities that increased investment in technical advancement and modernized industrial structures may also account for this decreasing trend. Additionally, the results of geographical heterogeneity demonstrate that the RCS's influence on curbing industrial water pollution is greater in cities with a higher intensity of environmental regulation and higher fiscal balance pressure than in locations with low environmental regulation and low fiscal balance pressure. In summary, the Chinese government needs to continue to strengthen the RCS's implementation; this can be done by adjusting to local circumstances as needed and by carrying out the policy accurately and effectively across the country. Our research sheds light on how to prevent water pollution in China and in other countries and supports the positive effects and effectiveness of RCS., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

As a developing country, China is facing serious water pollution and scarcity, which indicates the need for integrated water-resource and environmental regulations. Zoning policies have undergone significant advancements to enhance water-resource utilization in China. However, conflicts and overlaps still exist among these policies. To integrate these zoning policies and regulations, the "Three Lines One Permit" (TLOP) water-environment policy was formulated as a new framework, which included the goal for water quality, upper limits on water-resource utilization, and a permit list. This study presents the main achievements of the TLOP as a case-study in Jinan. The territories of Jinan were divided into 158 water-environment control-units (WECUs) and classified into two types of protected zones, three types of pollution-control zones, and ordinary zones. The total maximum pollutant-loads in the 158 WECUs, and 138 townships were calculated. The water-resource-utilization indicator values and ecological demand of key rivers were specified. The permit lists for the water environment at macroscale, mesoscale, and microscale were compiled from four perspectives: spatial constraints, emissions control, risk prevention, and resource utilization. Finally, suggestions were proposed to promote a more scientific and efficient TLOP policy to enhance human-water harmony.

The inter-provincial transboundary area of the Taihu Lake Basin is characterized by a complex river network and reciprocating flow. Frequent environmental pollution events in recent years have become a major safety hazard for the water quality in the Taihu Lake Basin. There are few early warning systems for environmental pollution events in China, the ability to simulate risk is insufficient, and systematic research on technology, development, and application is lacking. Thus, water management requirements are not met in the inter-provincial transboundary area of the Taihu Lake Basin. This paper proposes a cross-border risk management plan for pollution sources in the transboundary areas of the Taihu Lake Basin and an early warning and emergency response system for water pollution events using modern information technology. We used this system to assess and classify 2713 risk sources for nitrogen and phosphorus pollution into 5 categories. We simulated the discharge of a pollutant into a tributary and the early warning and emergency response for the transboundary region. The results indicate that the proposed early warning and emergency response system substantially improved the transboundary water environment and lowered the risk of pollution in the Taihu Lake watershed.

Cross-border illegal water pollution discharge (CIPD) occurs much frequently due to weak environmental supervision and unclear environmental rights. This paper attempts to explore the impact of cross-border ecological compensation policy (CBEC) on CIPD. By using day-night difference of pollution data at administrative boundary monitoring station, illegal water pollution discharge is calculated. Difference-in-differences-in-differences (DDD) model is used to estimate the impact of CBEC on CIPD. First, DDD results show that CBEC can effectively curb CIPD. Second, environmental regulatory effect, environmental governance effect and environmental awareness effect produced by CBEC are tested. CBEC inhibits CIPD by strengthening media supervision and public pollution reporting in environmental regulatory effect, and reduces CIPD by increasing environmental protection investment and environmental law enforcement efficiency in environmental governance effect, and curbs CIPD by promoting environmental information disclosure and reducing environmental corruption in environmental awareness effect. Third, by further analyzing different stages of CBEC, CIPD generated by environmental action coordination and environmental governance mechanism coordination is highly inhibited. Fourth, CBEC has a stronger inhibition effect on CIPD as upstream region is economically underdeveloped and downstream is economically developed. The conclusion provides policy implications from inter-government coordination for restraining CIPD., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In recent years, agricultural non-point source pollution (ANPSP) has become the biggest threat to Aras River water quality by completing the Mughan irrigation and drainage network. Nutrient pollutants, including nitrate and phosphate, released into the river through drains have created a range of obstacles for locals living around the river. Agricultural activities are generally considered the largest source of non-point pollution. They have no complex and uniform impact along the river. Thus, the spatial distribution of ANPS and highly polluted areas should be identified to manage watershed management. This study proposes a simple framework for identifying pollutant-sensitive areas along the river and management strategies to improve water quality. To this aim, the main factors affecting ANPSP were identified, and the effectiveness of the scenarios selected to comply with water quality regulations for drinking and environment during 1993-2007 were simulated. Based on the sensitivity analysis, land use and fertilizer are the main factors affecting river ANPSP. Thus, their changes were modeled in different scenarios. Based on the results, the ANPSP load was higher downstream. The agricultural lands in region 3 were considered the main source of pollution. Comparing the management scenarios showed that the amount of nitrate and phosphate leaching into the river decreased to 18.1 and 8.35 %, respectively, by reducing the consumption of urea and phosphate fertilizers by 50 %. The results help watershed managers implement eco-friendly land use and nutrient management programs at specific locations during specific periods to control ANPSP along the rivers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Floodgate operation is one of the main forms of river regulation in the development and utilization of river basins. It changes the natural structure, flow process, and correlative environment of rivers. However, there is little analysis of the multiple impacts of small floodgate operation on the water environment in river networks and of the regulation patterns of urban floodgate infrastructure on pollution. In this paper, a one-dimensional hydrodynamic-water quality model, MIKE 11, was used, taking Wuxi's two main pollutant indicators-the permanganate index (COD Mn ) and ammonia nitrogen (NH 3 -N)-to simulate the water quality response of Wuxi's river network based on different design solutions of urban floodgate infrastructure. The results show that among the three design scenarios, the order of the decreasing amplitude of the COD Mn and NH 3 -N concentrations was as follows: 1.4 m design solution scenario > 2.1 m design solution scenario > 0.7 m design solution scenario. Meanwhile, under the 1.4 m scenario, the maximum decrease in the COD Mn concentration reached 37.57%, and the maximum decrease in the NH 3 -N concentration reached 206%. In the entire river network system, the improvement in the water quality in the downstream area was significantly better than that in the upstream area. In addition, under the three scenarios of floodgate operation, the changes in pollutant concentrations during the flood season (June-September) were significantly lower than those during the dry season (October-February) and the flat water season (March-May). The research results can provide theoretical support and new ideas for future research on the ecological operation of small floodgates and related research on the water environment effect.

Campaign-style environmental implementation (CEI) is widely exerted in environmental protection, while its benefits and costs are controversial. We take advantage of the Central Environmental Protection Inspection (CEPI) System-a latest and distinguished form of CEI launched by China in 2016, as a quasi-natural experiment, to compare the benefits and costs of CEI based on water pollution effect estimates. Our results based on the annual panel data from 500 cities during 2009-2018 show that CEPI significantly reduced water pollution by an average of 20.7%. Further cost-benefit analysis based on the estimates of water pollution reduction shows that the potential health benefits of mortality and morbidity reduction resulting from CEPI are at least $12.26 billion, without bearing additional economic costs. We also explore why CEPI is cost-effective and find that CEPI reduces water pollution and becomes cost-effective mainly through deterring local officials, punishing polluting enterprises, and increasing public participation in environmental governance., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Water pollution is a major environmental problem worldwide, especially in developing countries. China's environmental protection strategies have been pushed to the highest priority in history, driving remarkable achievements in water pollution control, but were also coupled with new challenges. In this study, we analyzed diverse long-term data (i.e. water quality, WWTPs, pollutant discharge etc.) to systematically understand the process of water pollution control in China in the last twenty years. The results highlighted that the collection and treatment capacity of wastewater in China approached the developed country level, with the treatment rates exceeding 90% both in urban and country areas. The environmental quality of surface water was continuously improved, but water pollution problems remained in the river basins of eastern China, with remarkable economic progress. Rapid economic growth rather than population growth was the limiting factor for water pollution control in China. Therefore, more efforts should be made to further improve wastewater collection and treatment capacity and address the gap between effluent discharge limits for wastewater treatment plants and environmental quality standards for surface water. China's progress toward water pollution control provided important insights for other developing countries., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Water related problems, including water scarcity and pollution, have become increasingly urgent challenges especially in arid and semiarid regions. Two-dimensional water trading (2DWT) mechanism has been designed to unify the quantity and quality of water for relieving the water crisis. This study aims to develop a risk aversion optimization-two dimensional water trading model (RAO-2DWTM) for planning the regional-scale water resources management system (RWMS). This is the first attempt on planning RWMS through risk aversion optimization within the two-dimensional water trading framework. RAO-2DWTM cannot only support in-depth analysis regarding the effect of decision maker's preferences on system risk in different trading scenarios, but also reflect the interaction between water right trading and effluent trading, as well as disclose the optimal scheme of water resource management under uncertainties. Twenty four scenarios associated with different trading scenarios and robust levels are analyzed. The optimization scheme under the optimal risk control level is determined based on TOPSIS. Results revealed that 2DWT would bring high benefit with reduced risk cost, water deficit and emissions, implying the effectiveness of 2DWT mechanism. The results also disclosed that risk aversion behavior can mitigate water scarcity and pollution, as well as reduce risk cost, but may lead to some losses of system benefit. Consequently, decision makers should make trade-offs between system benefit and risk in identifying desired trading schemes., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

During the implementation of ecological protection in the Yellow River basin, understanding the water pollution status and spatio-temporal variation of water quality has become the most important thing for water safety in the basin. To analyze the water quality in recent years, the water quality data in the Yellow River basin from 2004 to 2018 were firstly collected from eight typical monitoring stations. Using a combination of multivariate data analysis methods including the Mann-Kendall (M-K) trend test, hierarchical clustering analysis (HCA), principal component analysis (PCA), and modified comprehensive water quality identification index (WQI), the spatio-temporal variation characteristics of the water quality were then explored in the Yellow River basin. The results indicated that in terms of time variation, the HCA from the water quality time series showed that the water quality of the Yellow River basin could be divided into the wet season, normal season, and dry season, being basically consistent with the hydrological period. Combined with the M-K trend test and WQI-based water quality assessment, the water quality of the Yellow River basin was improving gradually, with 2010 as the critical year. The water quality in the wet season was superior to that in the dry season. The pollution indicator NH 4 + -N and permanganate index were dominant in both the wet season and dry season. According to the spatial variation analysis, the water quality for all the studied stations improved significantly. Spatial clustering showed that the S6 (Shanxi Yuncheng Hejin Bridge) was obviously different from others, and further comparative study demonstrated that S6 was constantly seriously polluted. The S7 (Henan Jiyuan Xiaolangdi) exhibited different characteristics in the wet and dry season. In all stations, NH 4 + -N was considered to be the most common pollution indicator, whereas the permanganate index and DO were also relatively serious for S6. In different hydrological seasons, NH 4 + -N and the permanganate index showed different characteristics, and their variety was related to the fact that the former mainly came from domestic and industrial sources, whereas the latter was mainly derived from agricultural sources. The modified WQI showed obvious advantages over single-factor water quality assessment, and the findings from this study can provide scientific evidence for water pollution control and comprehensive water quality management in the Yellow River basin.

The effectiveness of campaign-style enforcement (CSE) on water pollution, especially the long-term effectiveness, is controversial, and little knowledge is known about the channels through which the effectiveness happens. We take advantage of China's Environmental Protection Interview (EPI)- a distinguished form of CSE launched in 2014, as a natural experiment to estimate the short-term and long-term effects of CSE on water pollution. Using a time-varying difference-in-differences model based on city panel data from 2006 to 2018, we find that EPI can lead to an average 14.5% reduction in water pollution, and this effect is still persistent in the long term. Mechanism analysis shows that EPI reduces water pollution mainly through the pressure effect on the government, the penalty effect on the firms, and the mobilization effect on the public. Heterogeneity analysis shows that the effect of EPI on water pollution is more significant in cities with high initial pollution, low public complaints, and low economic levels. Further cost-benefit analysis based on the estimated value of water pollution reduction shows that the upper health benefit of EPI is $520.97 billion, which is 4.87 times higher than its estimated cost of $107.05 billion., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The Action Plan for Water Pollution Prevention and Control (i.e., the "10-Point Water Plan") is a regulation formulated by China to prevent and control water pollution and ensure China's water safety. To test the policy effect of the "10-Point Water Plan", we use data from 269 cities for the period from 2012 to 2017 to examine whether the implementation of the plan can help reduce the intensity of industrial water pollution. The results show that the industrial water pollution intensity in Central and Western China is significantly higher than that in other regions, and the implementation of the "10-Point Water Plan" significantly reduces industrial water pollution intensity in China. We further find that upgrading industrial structures and technological innovation are effective ways to ameliorate the intensity of industrial water pollution. In terms of spatial heterogeneity, the impact of the "10-Point Water Plan" on reducing industrial water pollution is smaller in areas with high environmental regulation intensity than in areas with low environmental regulation intensity. We also find a strong inhibitory effect of environmental regulations on industrial water pollution intensity in areas with low environmental regulation intensity. Our findings support the positive policy effect of the "10-Point Water Plan" and provide significant policy implications for water pollution prevention and control actions in China and other countries., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Water pollution is a persistent problem in China, in part, because local governments fail to implement water quality standards set by national and provincial authorities. These higher authorities often lack regular information about the immediate and long-term achievement of remediation targets. Accordingly, central authorities have encouraged nongovernmental organizations to monitor local governments' remediation efforts. This study examines whether nongovernmental monitoring of urban waterways improves water quality by facilitating oversight of local governments or instigating public action for remediation. We randomly assigned urban waterways in Jiangsu province previously identified for remediation to be monitored by a partner nongovernmental organization for 15 mo. We further randomized whether the resulting information was disseminated to local and provincial governments, the public, or both. Disseminating results from monitoring to local and provincial governments improved water quality, but disseminating results to the public did not have detectable effects on water quality or residents' pursuit of remediation through official and volunteer channels. Monitoring can improve resource management when it provides information that makes local resource managers accountable to higher authorities., Competing Interests: The authors declare no competing interest.

At present, water pollution is still a serious problem in some parts of China. Clean water corridor technology (which provides water quality assurance and pollution load reduction from the Major Science and Technology Program for Water Pollution Control and Treatment) is a river pollution control and treatment measure. However, due to the differences of specific river conditions, it is not initially clear which technology can be used to obtain the best effect. Numerical simulation can address this issue. The results can be used as the basis for selecting clean water corridor technology. Combined with remote sensing (RS) and geographic information system (GIS) technology, the relationship between land use and non-point source pollution load was analyzed by using the HSPF (Hydrological Simulation Program-Fortran) model. According to the distribution of pollution load, the effect of the clear water corridor technology and its combination scenario on the reduction of non-point source pollution in the basin was simulated, and the best clear water corridor technology scheme for the control of non-point source pollution was identified. Research results show that from 2015 to 2018, the non-point source pollution load of total nitrogen in the Paihe River basin showed an overall increasing trend, while the total phosphorus showed a slightly increasing trend. Agricultural land and construction land accounted for 70% and 20%, respectively, of the non-point source pollution load, and the change in land use played an important role in the load of non-point source pollution. In terms of spatial distribution, the non-point source pollution of total nitrogen and total phosphorus was mainly concentrated in the downstream region and the central region. The non-point source pollution load reduction rates of total nitrogen and total phosphorus by the three types of clean water corridor technologies of vegetation buffer zones, permeable sidewalks and constructed wetlands, and their combinations were 15.29% and 15.03%, 11.93% and 11.48%, 8.96% and 8.67%, and 24.12% and 23.20%, respectively. It is necessary to comprehensively adopt clean water corridor technology for an optimal allocation and reasonable layout and to increase the pollution load reduction rate to further achieve ecological environment restoration goals.

Climate change, population growth, the development of industrialization and urbanization are increasing the demand for water resources, but the water pollution is reducing the limited water supply. In recent years, the gap between water supply and demand which shows water scarcity situation is becoming more serious. Clear knowing this gap and its main driving factors could help us to put forward water protection measures correctly. We take the data of Huaihe River Basin from 2001 to 2016 as an example and use ecological water footprint to describe the demand, with the water carrying capacity representing the supply. We analyze the water supply-demand situation of Huaihe River Basin and its five provinces from footprint view in time and space. Then we apply the Logarithmic Mean Divisia Index model to analyze the driving factors of the ecological water footprint. The results show that: (1) the supply and demand balance of Huaihe River Basin was only achieved in year 2003 and 2005. There is also a large difference between Jiangsu province and other provinces in Huaihe River basin, most years in Jiangsu province per capital ecological footprint of water is more than 1 hm2/person except the years of 2003, 2015, and 2016. But other provinces are all less than 1 hm2/person. (2) Through the decomposition of water demand drivers, we concluded that economic development is the most important factor, with an annual contribution of more than 60%. Our study provides countermeasures and suggestions for the management and optimal allocation of water resources in Huaihe River Basin, and also provides reference for the formulation of water-saving policies in the world., Competing Interests: China Water Resources Huai River Planning, Design & Research CO.LTD had no competing interest in this paper. The authors have declared that no competing interests exist.

Considering the situation of the frequent turnover of Chinese environmental protection officials (EPOT), this paper analyzes its impact on transboundary water pollution. The results show that EPOT can reduce transboundary pollution. EPOT can reduce the concentration of DO by 0.261 and NH3-N by 0.167 in the downstream river. And the impact shows a first strong and then weak change over time. EPOT can restrain transboundary pollution by reducing the production of polluting enterprises and promoting public pollution reporting, and it aggravates transboundary pollution by reducing environmental law enforcement and collaborative governance. In addition, the impact of EPOT on transboundary pollution has a distance effect. Within the regulatory distance of 50 km, EPOT has strong inhibition on transboundary pollution. When the governor and the environmental protection official (EPO) change tenure at the same time, the inhibition of transboundary pollution is the strongest. In addition, EPOs from the central government and with working experience in environmental protection departments can control transboundary pollution better.

The Water Sediment Regulation Scheme (WSRS) is a unique engineering measure that has been regularly performed to reduce reservoir sedimentation and increase the flood capacity of the Yellow River in China since 2002. As a side effect, the WSRS greatly increases the monthly input flux of nutrients to the Bohai Sea (BHS) in summer, potentially exacerbating eutrophication levels therein and subsequently affecting the growth of phytoplankton. However, its influence on the Chlorophyll-a (Chl-a) dynamics over the BHS is still poorly understood. In this study, two approaches were adopted to investigate it: 1) long-term in-situ observations and satellite-derived data of surface Chl-a were used to study its seasonal variations before and since 2002, and 2) one 1D physical-biological coupled model was developed to evaluate the impact of WSRS on seasonal Chl-a. The results showed that the surface Chl-a exhibited two peaks in spring and autumn until 2002, but has exhibited only one peak in spring-summer since 2002. Satellite-derived Chl-a concentrations in spring-summer since 2002 have increased by 56% compared to those until 2002. The simulated results showed that the change in Yellow River discharge induced by the WSRS has resulted in the appearance of high concentrations of Chl-a in summer over the Central Bohai Sea since 2002. The WSRS increased the ratio of added Chl-a owing to the riverine nutrients to total Chl-a by 19% compared to that until 2002. Overall, WSRS greatly affects the seasonal cycling of Chl-a in the Bohai Sea, and the side effect needs to be considered., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The River Chief Policy (RCP) is an innovative water resource management system in China aimed at managing water pollution and improving water quality. Though the RCP has been piloted in some river basins of China, few scholars have studied the effects of the policy. We built a differential game model under random interference factors to compare the water pollution in Chaohu Lake under the RCP and without the RCP, and we explored the conditions to ensure the effectiveness of the RCP. The results showed that: (1) The average effect of water pollution control under the RCP was greater than under non-RCP; (2) the higher the rewarding excellence and punishing inferiority coefficient ( θ ) was, the better the water pollution control effect under the RCP; (3) the greater the random interference coefficient ( σ ) and rewarding excellence and punishing inferiority coefficient ( θ ) were, the bigger the fluctuation of the water pollution control effect was; (4) when using the stochastic differential game, when σ ≤ 0.0403 , θ ≥ 0.0063 , or σ > 0.0403 , θ ≥ 0.268 , the RCP must be effective for water pollution control. Therefore, we can theoretically adjust the rewarding excellence and punishing inferiority coefficient ( θ ) and the random interference coefficient ( σ ) to ensure the effective implementation of the RCP and achieve the purpose of water pollution control.

A major inland alkalinity lake in Northeast China, the Chagan Lake, was studied for the changes of its water qualities over the past three decades. Water quality data, including total nitrogen (TN), total phosphorus (TP), pH, dissolved oxygen (DO), and fluoride (F - ), were analyzed to derive key indices for guiding water quality management. Our study found that the Chagan Lake had an average trophic state index (TSI) ranging 50 to 70; the average TSI for TP ranging between 70 and 80, and the average TSI for TN being 50. Over the past three decades, the TSI values generally trended lower, but there was a slight uptrend from 2012 onwards. Seasonal variations in the concentrations of TN and TP were identified. The TSI values in September were higher than those in May, while the values of un-ionized ammonia (UIA) during rainy seasons were higher than those during dry seasons. The average values of alkalinity and F - in the lake water exceeded the upper limits set in the Chinese water quality standards, i.e., 20 mg/L and 1 mg/L, respectively. It was defined that the evolution of lake water quality proceeded in four consecutive periods, namely natural, deterioration, improvement, and risk period; the improvement period benefitted from a historical water conservation project. Our study concluded that the amount of irrigation discharge into the Chagan must be monitored, and controlled, in order to sustain the critical ecological functions currently provided by the Chagan Lake.

With the significant economic shift, water pollution treatment has gradually become a key problem which needs to be deeply investigated for the sustainable development of China. In the face of specific water pollution incidents, multiple alternatives are often required to work together in order to achieve better results. However, due to the limitation of resources, alternatives must be ranked to realize the effective allocation of resources, which means the more highly ranked ones should possess more disposable resources. Furthermore, the water pollution treatment process is a multi-stage and multi-objective process. In each stage, decision-makers may have different emphasis and thus have different preferences for the treatment alternatives. How to effectively aggregate decision-makers' preferences in different stages into an overall preference so as to form a ranking of treatment alternatives under global constraints has turned into a problem worthy of discussion. Under such background, this paper proposes a multi-stage gray group decision-making method, where decision-makers use Group-G1 to rank and weight the criteria, and in this way, the weights of decision-makers and criteria in each stage could be determined. Considering the difference and deficiency of the cognitive level of decision-makers, this paper adopts the form of hesitant fuzzy linguistic term sets (HFITS) to express the evaluation information of decision-makers. And then, gray incidence analysis is selected to rank the alternatives. After ranking the alternatives in each stage, the multi-stage rankings will be aggregated into an overall ranking and the resource allocation is made according to the priorities of the alternatives. Finally, an example of water pollution treatment alternatives ranking based on a cyanobacterial bloom in Taihu Lake, China, is given to illustrate the proposed approach.

The study on the quantification of ecological compensation (eco-compensation) in a river basin can help to make environmental protection more compatible with ecological construction. In this paper, the upstream and downstream of the river basin were treated as the subjects and objects of eco-compensation, and the mechanism of eco-compensation was clarified. The emergy analysis theory (EMA) was used to calculate the values of water resources in sub-industries (agriculture, industry, life, and recreation). The pollution loss rate theory (PLR) was adopted to calculate the water pollution loss rate in sub-industries. According to the value of water resources and pollution loss rate in sub-industries, combined with the water consumption of sub-industries in the river basin, the Ecological Compensation Quantification Model of Sub-industries (ECQ-Is Model) was constructed. Under the guidance of the aforementioned theory and model, a comprehensive research was conducted on the Xiaohong River. The results showed that the eco-compensation values of the upstream area, industry, and agriculture in the river basin were higher. Therefore, it is essential that the water resources in the Xiaohong River basin be well conserved and managed. In addition, the research results point out the direction for water pollution control, which includes promoting the coordinated development of the upstream and downstream, and maximizing the ecological benefits of the river basin.

To address stormwater management, China initiated the construction of sponge cities (SPCs) in 2014. Sponge city construction in China has previously been evaluated using subjective expert methods. Based on China's SPC evaluation regulations, the evaluation criteria system was divided into 6 categories and 22 indicators. This study presents a multicriteria approach to evaluating SPC construction through multicriteria attributes value theory (MAVT). Coupled with the entropy method, this approach can reduce errors caused by individual methods. This work improved the evaluation method from a subjective to an objective method. Additionally, the sensitivity of an alternative to these criteria was conducted. The analysis reveals the inner relationship between the SPC alternative and the criteria. The city of Hebi, an actual SPC project, was selected as a case study. The findings indicate that the proposed approach is efficient and simple. It can help decision makers better understand SPC performance, and it is a pilot SPC evaluation method using relatively objective means. Integr Environ Assess Manag 2019;15:703-713. © 2019 SETAC., (© 2019 SETAC.)

The soil permeability and underground water level greatly affect the performance of low-impact development (LID) practices. Shanghai is located in the area of estuary and is characterized by its high groundwater level and low soil infiltration rate. The LID practices in Fuxing Island Park, Shanghai, including a bioretention cell, swales, a permeable pavement, and a combined LID practices were studied in the present paper. The performance of LID practices during the period of eight rainfall events was evaluated in terms of hydrology and water quality. Due to the detention of the LID practices, a significant delay between the peak rainfall and the peak surface runoff was observed. On-site tests show it is suitable for the applicability of LID in a rainy city with low soil infiltration rate and high groundwater level. Moreover, the Stormwater Management Model (SWMM) was also used to compare the hydrologic effects before and after these four LID practices application in the park. Results indicated the LID practices could effectively reduce the runoff volume and the peak flow in the park. Furthermore, the runoff water quality evaluation showed the pollutants were effectively removed by these four LID practices due to both runoff treatment and flow volume reduction. The bioretention system proved to be effective as a result of its larger facility area while the swales had the obvious reduction volume both per facility area and per catchment area.

Slag heaps are formed by mining waste materials, and the improper treatment of leachate from such heaps can threaten nearby aquifers. The Zhehai slag heap in Yunnan Province, China, contains 2.7 million tons of zinc and cadmium slag, and is considered a heavy metal source threatening the local groundwater safety, however, the severity of contamination remains unknown. In this study, numerical modeling was used to predict the groundwater flow and contaminant transport in this area based on field data. The results show that the atmospheric precipitation infiltration recharge at the top of the heap is 81.8 m³/d, accounting for 93.76% of total infiltration. The south and east sides of the area are the main outflow channels for contaminants, accounting for 93.25% of the total discharge around the heap. To reduce aquifer contamination, an in situ system involving a "controlling the source, 'breaking' the path, and intercepting the flow" (CSBPIF) strategy is established. The results indicate that the system performs well because it not only decreases the flow velocity but also reduces the concentrations of contaminants adsorbed by clay media. Moreover, the equivalent bottom liner thicknesses of the clay layers were calculated to improve the applicability of the CSBPIF system. Compared with ex situ disposal, this scheme provides an economic and effective solution and can be used to prevent and control groundwater pollution in China.

The continuous deterioration of the aquatic environment in rivers and streams is increasingly causing social and political tensions. To alleviate aquatic environmental problems, especially for the nonpoint source pollution, establishment of riparian forest buffers has been demonstrated as an effective control measure. However, few comprehensive studies of the reduction effects of riparian reforestation on the aquatic environment have been performed, particularly in identifying the suitable widths of reforestation projects. In this paper, the Annualized Agricultural Non-Point Source (AnnAGNPS) model was used to simulate the reduction effects of riparian reforestation on runoff and nutrient loads in Wucun watershed, China. The results showed that 20-m, 40-m, and 60-m widths of riparian buffer reforestation had significant effects on the yearly loads of total nitrogen (TN) and total phosphorus (TP), with reduced rates of 23.21 to 56.2% and 18.16 to 52.14%, respectively. The reduction effect on annual runoff varied from 2.8 to 5.4%. Furthermore, the reduction effect of nutrients performed best during the transition period, while the best runoff reduction was found during the dry period. These distinct reductions indicated that the implementation of riparian forest buffers was capable of reducing the risk and frequency of flooding and eutrophication, especially during the wet and transition periods. Additionally, the 20-m width of riparian buffer reforestation achieved the highest reduction efficiency for runoff, and the 40-m width was the most suitable reforested riparian buffer width for TN and TP. Therefore, 40 m may be the optimum buffer width for the implementation of riparian reforestation in the Wucun watershed. These research results provided scientific information on selecting the optimum buffer width for aquatic environmental regulators and managers as the reduction effects of different widths of riparian buffers on runoff and nutrients were different when considering buffer reforestation.

Vegetable production in solar greenhouses in northern China results in the excessive use of nitrogen (N) fertilizers and water via flooding irrigation. Both factors result in low N use efficiency and high environmental costs because groundwater becomes contaminated with nitrate (NO 3 - ). Four consecutive tomato (Lycopersicum esculentum Mill.) cropping seasons were tested whether drip fertigation and/or the incorporation of maize straw (S) may significantly reduce NO 3 - and dissolved organic N (DON) leaching while increasing the water-use efficiency (WUE) and partial factor productivity of applied N (PFP N ) of the tomatoes. The following treatments were used: ① conventional flooding irrigation with overfertilization (CIF, 900 kg N ha -1 season -1 ), ② CIF + S, ③ drip irrigation with optimized fertilization (DIF, 400 kg N ha -1 season -1 ), ④ DIF + S. We found that (1) DIF significantly increases the PFP N and WUE by 262% and 73% without compromising the yield compared with CIF, respectively. (2) For CIF, approximately 50% of the total N input was leached at a NO 3 - /DON ratio of approximately 2:1. (3) Compared with CIF, DIF reduced NO 3 - and DON leaching by 88% and 90%, respectively. Water percolation was positively correlated with N leaching (p < 0.001). (4) Straw application only reduced NO 3 - leaching losses in the first year and did not affect DON leaching overall, although DON leaching was increased in DIF in the first growing season. In conclusion, DIF significantly reduces NO 3 - and DON leaching losses by approximately 90% compared with the current farmer practice (CIF). Considering the significant DON leaching losses, which have been overlooked because previous measurements focused on NO 3 - , DON should be considered as a primary factor of environmental pollution in conventional solar greenhouse vegetable production systems., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

In this study, a Bayesian risk-induced interval stochastic modeling framework (BRISF) is proposed for planning effluent trading program among point and nonpoint sources as well as identifying interactions of important trading factors under system risk. BRISF incorporates nutrient fate modeling with soil and water assessment tool (SWAT), Bayesian inference with random walk Metropolis algorithm (RWM), and constraint-violation risk-based two-stage stochastic programming (CRTSP) within a general framework. Bayesian inference is employed for uncertainty analysis of SWAT model parameters and uncertain prediction of nutrient loadings; this process provides the random inputs for optimization process. CRTSP is capable of dealing with multiple uncertainties in modeling effluent trading program as well as system risk of environmental allowance violation. BRISF is applied to a real case of Xiangxihe watershed in China for water quality management. Solutions for optimal trading scheme corresponding to different risk levels are generated. Thousands of scenarios are examined to analyze the individual and interactive effects of trading ratios and treatment rates on trading system. Comparison between cross-industry and intra-industry effluent trading scheme is also conducted. It is proved that cross-industry trading would bring about higher benefit with reduced pollution loading; cross-industry effluent trading scheme would be recommended to achieve optimal water quality management and system benefit., (Copyright © 2018 Elsevier Inc. All rights reserved.)

To cope with challenges of food security and water scarcity in rice production, water-saving ground cover rice production systems (GCRPSs) are increasingly adopted in China and globally. Reduced soil moisture as well as increased soil aeration and temperature under GCRPSs may promote soil N transformations, and in turn give rise to environmental challenges. These include emissions of the potent greenhouse gas nitrous oxide (N 2 O) and atmospheric pollutant nitric oxide (NO). Using conventional flooding rice cultivation as a reference, a three-year field experiment was conducted to investigate the performances of GCRPSs under inorganic (urea) or integrated nutrient management (a combination of synthetic and organic fertilizers), with regards to soil N 2 O and NO emissions as well as grain yields. N 2 O and NO emissions in GCRPSs exhibited high seasonal and interannual variations along with changes in soil inorganic N content and rainfall. When urea alone was applied, the average N 2 O and NO emissions from GCRPSs were 4.11 and 0.14 kg N ha -1 , respectively. These emissions were significantly higher than those of conventional rice cultivation, with 1.47 and 0.052 kg N ha -1 for N 2 O and NO, respectively. When integrated nutrient management was performed for GCRPSs, N 2 O and NO emissions were reduced by approximately 77% and 50%, respectively, i.e., the emission magnitude comparable with N-trace gas losses from conventional rice cultivation. Moreover, GCRPSs with integrated nutrient management resulted in optimal grain yields, and thus, the yield-scaled N 2 O + NO emissions were the lowest compared to other treatments. Averaged over 3 years, the direct emission factors of N 2 O and NO for GCRPSs with urea alone were 2.58% and 0.064%, respectively. Those for GCRPSs with integrated nutrient management were 0.48% and 0.016%, respectively. The results of this study suggest that GCRPS with integrated nutrient management is an eco-friendly strategy for optimizing crop yields while mitigating N 2 O and NO emissions., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Enteric viruses in surface water pose considerable risk to morbidity in populations living around water catchments and promote outbreaks of waterborne diseases. However, due to poor understanding of the correlation between water quality and the presence of human enteric viruses, the failure to assess viral contamination through alternative viral indicators makes it difficult to control disease transmission., Methods: We investigated the occurrence of Enteroviruses (EnVs), Rotaviruses (HRVs), Astroviruses (AstVs), Noroviruses GII (HuNoVs GII) and Adenoviruses (HAdVs) from Jinhe River over 4 years and analyzed their correlation with physicochemical and bacterial parameters in water samples., Results: The findings showed that all target viruses were detected in water at frequencies of 91.7% for HAdVs, 81.3% for HuNoVs GII, 79.2% for EnVs and AstVs, and 70.8% for HRVs. These viruses had a seasonal pattern, which showed that EnVs were abundant in summer but rare in winter, while HAdVs, HRVs, AstVs, and HuNoVs GII exhibited opposite seasonal trends. Pearson correlation analysis showed that total coliforms (TC) was significantly positively correlated with EnVs concentrations while no consistent significant correlations were observed between bacterial indices and viruses that precipitate acute gastroenteritis., Conclusions: Taken together, the findings provide insights into alternative viral indicators, suggesting that TC is a potentially promising candidate for assessment of EnVs contamination. However, it failed to predict the presence of HAdVs, HRVs, AstVs, and HuNoVs GΙΙ in surface water across the city of Tianjin.

Source water nutrient management to prevent eutrophication requires critical strategies to reduce watershed phosphorus (P) loadings. Shanxi Drinking-Water Source Area (SDWSA) in eastern China experienced severe water quality deterioration before 2010, but showed considerable improvement following application of several watershed management actions to reduce P. This paper assessed the changes in total phosphorus (TP) concentrations and fluxes at the SDWSA outlet relative to watershed anthropogenic P sources during 2005⁻2016. Overall anthropogenic P inputs decreased by 21.5% over the study period. Domestic sewage, livestock, and fertilizer accounted for (mean ± SD) 18.4 ± 0.6%, 30.1 ± 1.9%, and 51.5 ± 1.5% of total anthropogenic P inputs during 2005⁻2010, compared to 24.3 ± 2.7%, 8.8 ± 10.7%, and 66.9 ± 8.0% for the 2011⁻2016 period, respectively. Annual average TP concentrations in SDWSA decreased from 0.041 ± 0.019 mg/L in 2009 to 0.025 ± 0.013 mg/L in 2016, a total decrease of 38.2%. Annual P flux exported from SDWSA decreased from 0.46 ± 0.04 kg P/(ha·a) in 2010 to 0.25 ± 0.02 kg P/(ha·a) in 2016, a decrease of 44.9%. The success in reducing TP concentrations was mainly due to the development of domestic sewage/refuse collection/treatment and improved livestock management. These P management practices have prevented harmful algal blooms, providing for safe drinking water.

Background: The near-surface urban drainage system in Shanghai is highly complex, with hundreds of thousands of catch basins (CBs) and manhole chambers (MCs). Comparatively little is known about the breeding of mosquitoes in this vast system, especially for the locally predominant species Aedes albopictus. A cross-sectional mosquito sampling study was conducted from late July to early August of 2017 using 539 CBs and 309 MCs located in 10 communities of downtown Shanghai. We measured the water-holding status of the drainage systems and density of mosquito larvae. Mosquito species were examined on site and in the laboratory later., Results: The CBs were characterized by a lower percentage of standing water compared to MCs (47.0% vs. 79.9%, respectively; X2 = 76.407, P<0.001), but CBs contained a higher percentage of stagnant water percent than MCs (45.2% vs. 35.3%, respectively; X2 = 11.465, P = 0.001). There were exclusively two species of mosquito larvae found in the drainage systems, Ae. albopictus and Culex pipiens complex. Compared with MCs, the structures of CBs were more conducive to larval production and yielded more larvae-positive samples (43.4% vs 14.2%, X2 = 53.136, P<0.001) and higher larval density (8.23 vs. 4.09 per dipper, t = 3.287, P = 0.001). Aedes albopictus was the predominant species in CBs, with a constituent ratio of 71.7%. Regarding structures with different features in different locations, CBs that had a vertical grate with an unsealed lid and MCs with plastic composite covers were the most favorable types for mosquito breeding, and residential neighborhoods yielded the highest number of Ae. albopictus., Conclusion: Aedes albopictus was the predominant species in both CBs and stormwater MCs, especially in residential neighborhoods. CBs, particularly those with vertical grates, were a major source of mosquito production in downtown Shanghai. MCs featured more running water and fewer larvae by percentage, and few larvae were found in Sewage MCs. However, due to the tremendous baseline amount, MCs were still an important breeding source of mosquitoes. We suggest that Aedes control in Shanghai should focus on CBs or other potential larvae habitats in and around residential neighborhoods. The use of permeable materials and completely sealed covers should be adopted in the construction of CBs and MCs henceforth., Competing Interests: The authors declare that they have no competing interests.

Transboundary water pollution has resulted in increasing conflicts between upstream and downstream administrative districts. Ecological compensation is an efficient means of restricting pollutant discharge and achieving sustainable utilization of water resources. The tri-provincial region of Taihu Basin is a typical river networks area. Pollutant flux across provincial boundaries in the Taihu Basin is hard to determine due to complex hydrologic and hydrodynamic conditions. In this study, ecological compensation estimation for the tri-provincial area based on a mathematical model is investigated for better environmental management. River discharge and water quality are predicted with the one-dimensional mathematical model and validated with field measurements. Different ecological compensation criteria are identified considering the notable regional discrepancy in sewage treatment costs. Finally, the total compensation payment is estimated. Our study indicates that Shanghai should be the receiver of payment from both Jiangsu and Zhenjiang in 2013, with 305 million and 300 million CNY, respectively. Zhejiang also contributes more pollutants to Jiangsu, and the compensation to Jiangsu is estimated as 9.3 million CNY. The proposed ecological compensation method provides an efficient way for solving the transboundary conflicts in a complex river networks area and is instructive for future policy-making.

As urbanization progresses, increasingly impervious surfaces have changed the hydrological processes in cities and resulted in a major challenge for urban stormwater control. This study uses the urban stormwater model to evaluate the performance and costs of low impact development (LID) scenarios in a micro urban catchment. Rainfall-runoff data of three rainfall events were used for model calibration and validation. The pre-developed (PreDev) scenario, post-developed (PostDev) scenario, and three LID scenarios were used to evaluate the hydrologic performance of LID measures. Using reduction in annual runoff as the goal, the best solutions for each LID scenario were selected using cost-effectiveness curves. The simulation results indicated that the three designed LID scenarios could effectively reduce annual runoff volumes and pollutant loads compared with the PostDev scenario. The most effective scenario (MaxPerf) reduced annual runoff by 53.4%, followed by the sponge city (SpoPerf, 51.5%) and economy scenarios (EcoPerf, 43.1%). The runoff control efficiency of the MaxPerf and SpoPerf scenarios increased by 23.9% and 19.5%, respectively, when compared with the EcoPerf scenario; however, the costs increased by 104% and 83.6%. The reduction rates of four pollutants (TSS, TN, TP, and COD) under the MaxPerf scenario were 59.8-61.1%, followed by SpoPerf (53.9-58.3%) and EcoPerf (42.3-45.4%), and the costs of the three scenarios were 3.74, 3.47, and 1.83 million yuan, respectively. These results can provide guidance to urban stormwater managers in future urban planning to improve urban water security., Competing Interests: The authors declare no conflict of interest.

In this study, an interval-stochastic-based risk analysis (RSRA) method is developed for supporting river water quality management in a rural system under uncertainty (i.e., uncertainties exist in a number of system components as well as their interrelationships). The RSRA method is effective in risk management and policy analysis, particularly when the inputs (such as allowable pollutant discharge and pollutant discharge rate) are expressed as probability distributions and interval values. Moreover, decision-makers' attitudes towards system risk can be reflected using a restricted resource measure by controlling the variability of the recourse cost. The RSRA method is then applied to a real case of water quality management in the Heshui River Basin (a rural area of China), where chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and soil loss are selected as major indicators to identify the water pollution control strategies. Results reveal that uncertainties and risk attitudes have significant effects on both pollutant discharge and system benefit. A high risk measure level can lead to a reduced system benefit; however, this reduction also corresponds to raised system reliability. Results also disclose that (a) agriculture is the dominant contributor to soil loss, TN, and TP loads, and abatement actions should be mainly carried out for paddy and dry farms; (b) livestock husbandry is the main COD discharger, and abatement measures should be mainly conducted for poultry farm; (c) fishery accounts for a high percentage of TN, TP, and COD discharges but a has low percentage of overall net benefit, and it may be beneficial to cease fishery activities in the basin. The findings can facilitate the local authority in identifying desired pollution control strategies with the tradeoff between socioeconomic development and environmental sustainability.

To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs.

A key issue facing integrated water resources management and water pollution control is to address the vague parametric information. A full credibility-based chance-constrained programming (FCCP) method is thus developed by introducing the new concept of credibility into the modeling framework. FCCP can deal with fuzzy parameters appearing concurrently in the objective and both sides of the constraints of the model, but also provide a credibility level indicating how much confidence one can believe the optimal modeling solutions. The method is applied to Heshui River watershed in the south-central China for demonstration. Results from the case study showed that groundwater would make up for the water shortage in terms of the shrinking surface water and rising water demand, and the optimized total pumpage of groundwater from both alluvial and karst aquifers would exceed 90% of its maximum allowable levels when credibility level is higher than or equal to 0.9. It is also indicated that an increase in credibility level would induce a reduction in cost for surface water acquisition, a rise in cost from groundwater withdrawal, and negligible variation in cost for water pollution control., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Two typical rural water utilities in Beijing, China were chosen to describe the principles and applications of water safety plans (WSP), to provide a methodological guide for the actual application and improve the quality of rural drinking water quality, and to establish an appropriate method for WSP applied in rural water supply. Hazards and hazardous events were identified and risk assessment was conducted for rural water supply systems. A total of 13 and 12 operational limits were defined for two utilities, respectively. The main risk factors that affect the water safety were identified in water sources, water processes, water disinfection systems and water utility management. The main control measures were strengthening the water source protection, monitoring the water treatment processes, establishing emergency mechanisms, improving chemical input and operating system management. WSP can be feasibly applied to the management of a rural water supply.

Point source pollution is one of the main threats to regional environmental health. Based on a water quality model, a methodology to assess the regional risk of point source pollution is proposed. The assessment procedure includes five parts: (1) identifying risk source units and estimating source emissions using Monte Carlo algorithms; (2) observing hydrological and water quality data of the assessed area, and evaluating the selected water quality model; (3) screening out the assessment endpoints and analyzing receptor vulnerability with the Choquet fuzzy integral algorithm; (4) using the water quality model introduced in the second step to predict pollutant concentrations for various source emission scenarios and analyzing hazards of risk sources; and finally, (5) using the source hazard values and receptor vulnerability scores to estimate overall regional risk. The proposed method, based on the Water Quality Analysis Simulation Program (WASP), was applied in the region of the Taipu River, which is in the Taihu Basin, China. Results of source hazard and receptor vulnerability analysis allowed us to describe aquatic ecological, human health, and socioeconomic risks individually, and also integrated risks in the Taipu region, from a series of risk curves. Risk contributions of sources to receptors were ranked, and the spatial distribution of risk levels was presented. By changing the input conditions, we were able to estimate risks for a range of scenarios. Thus, the proposed procedure may also be used by decisionmakers for long-term dynamic risk prediction., (© 2014 Society for Risk Analysis.)

The estimation and allocation of water environmental capacity (WEC) are essential to water quality management and social-economic interests. However, there is inevitable uncertainty in the capacity estimation due to model conceptualization, data collection and parameter calibration. An innovative holistic approach was developed, which took both independence and relevance between parameters into account to analyze the uncertainties in WEC calculation and estimate the margin of safety. The Dongjiang River was taken as the case to demonstrate the method, focusing on the chemical oxygen demand and NH4(+)-N that were the two major water quality problems in the river. The results showed that the proposed holistic approach is very promising and applicable compared to traditional methods of uncertainty analysis., (Copyright © 2014. Published by Elsevier B.V.)

China is confronting the challenge of accelerated lake eutrophication, where Lake Dianchi is considered as the most serious one. Eutrophication control for Lake Dianchi began in the mid-1980s. However, decision makers have been puzzled by the lack of visible water quality response to past efforts given the tremendous investment. Therefore, decision makers desperately need a scientifically sound way to quantitatively evaluate the response of lake water quality to proposed management measures and engineering works. We used a water quality modeling based scenario analysis approach to quantitatively evaluate the eutrophication responses of Lake Dianchi to an under-construction water diversion project. The primary analytic framework was built on a three-dimensional hydrodynamic, nutrient fate and transport, as well as algae dynamics model, which has previously been calibrated and validated using historical data. We designed 16 scenarios to analyze the water quality effects of three driving forces, including watershed nutrient loading, variations in diverted inflow water, and lake water level. A two-step statistical analysis consisting of an orthogonal test analysis and linear regression was then conducted to distinguish the contributions of various driving forces to lake water quality. The analysis results show that (a) the different ways of managing the diversion projects would result in different water quality response in Lake Dianchi, though the differences do not appear to be significant; (b) the maximum reduction in annual average and peak Chl-a concentration from the various ways of diversion project operation are respectively 11% and 5%; (c) a combined 66% watershed load reduction and water diversion can eliminate the lake hypoxia volume percentage from the existing 6.82% to 3.00%; and (d) the water diversion will decrease the occurrence of algal blooms, and the effect of algae reduction can be enhanced if diverted water are seasonally allocated such that wet season has more flows., (© 2013.)