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Aiming at the problem of signal timing at road intersections, this paper uses the artificial bee colony algorithm to optimize the road model of single point multi phase intersection. In this paper, the cost function is the weighted sum of the average delay time, the average number and the capacity. Using the artificial bee colony algorithm to optimize the signal timing of a typical crossroad, and using MATLAB experimental platform to simulate, it shows that the artificial bee algorithm can enhance the road traffic efficiency.

Social economy in Huaihe River Basin had undergone enormous changes during 19902010. The grain yield had increased by 58%, from 64.14 million tons to 101.21 million tons, and the urbanization rate had increased by 22%, from 13% to 35%. Assessing the negative impacts of these high intensive human activities caused by rapid social development on terrestrial ecosystem would serve as a scientific basis for quantitative management of regional ecology. This paper estimated the spatial and temporal distribution of net anthropogenic nitrogen input (NANI) in Huaihe River Basin during 1990-2010. The results showed that there was an increasing trend in NANI in the period of 1990-2001, and after that this trend was slower. The NANI increased from approximately 17232 kg N · km-2 · a-1 in 1990 to a peak of 28771 kg N · km-2 . a-1 in 2003, and then declined to 26415 kg N · km-2 · a-1 in 2010. Chemical fertilizer and atmospheric deposition were the largest two sources of NANI, followed by food & feed import and biological nitrogen. Contributions from both chemical fertilizer and atmospheric deposition had been increasing continuously, respectively from 64% and 16% in 1990 to 77% and 19%. Our findings implied that the shift from fertilizer-supported agriculture and fossil fuel-supported industry to sci-tech lead economic development is urgently needed. [ABSTRACT FROM AUTHOR]

Phosphorus is an important limiting factor of water eutrophication. A clear understanding of its budget and regulated method is fundamental for reservoir ecological health. In order to promote systematic research further and improve phosphorus regulation system, the budget balance of reservoir phosphorus and its influencing factors were concluded, as well as conventional regulation and control measures. In general, the main phosphorus sources of reservoirs include upstream input, overland runoff, industrial and domestic wastewater, aquaculture, atmospheric deposition and sediment release. Upstream input is the largest phosphorus source among them. The principal output path of phosphorus is the flood discharge, the emission load of which is mainly influenced by drainage patterns. In addition, biological harvest also can export a fraction of phosphorus. There are some factors affecting the reservoir phosphorus balance, including reservoirs' function, hydrological conditions, physical and chemical properties of water, etc. Therefore, the phosphorus bud gets of different reservoirs vary greatly, according to different seasons and regions. In order to reduce the phosphorus loading in reservoirs, some methods are carried out, including constructed wetlands, prefix reservoir, sediment dredging, biomanipulation, etc. Different methods need to be chosen and combined according to different reservoirs' characteristics and water quality management goals. Thus, in the future research, it is reasonable to highlight reservoir ecological characteristics and proceed to a complete and systematic analysis of the inherent complexity of phosphorus budget and its impact factors for the reservoirs' management. Besides, the interaction between phosphorus budget and other nutrients in reservoirs also needs to be conducted. It is fundamental to reduce the reservoirs' phosphorus loading to establish a scientific and improved management system based on those researches. [ABSTRACT FROM AUTHOR]

Nitrogen (N) inputs caused by human activities potentially influences the aquatic environment. However, researches on N pollution in China are mainly discussed from the microscopic point of view, i. e. field experiment. Watershed-scale diagnosis of N pollution has just started, leading to ambiguous identification of ecological problems, pollution issues and pollution potential at watershed scale. In this paper, relationships between net anthropogenic N inputs (NANI) and riverine N flux (RNF) and factors influencing these relationships at watershed scale had been investigated. This would help diagnose ecological and environmental problems at watershed scale, understand the roles of natural climate and human activities in affecting N fluxes, and ultimately provide both theoretical and practical insights into environmental management decisions. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) has been widely used in the eco-environment field, but with shortcomings in revealing the laws of natural science, such as insufficient generalization ability and poor interpretability. In order to overcome these shortages and tap into complementary advantages, coupling AI and eco-environmental models containing physical mechanism has been a new research method with fast development in recent years. We introduced the classifications of AI used in eco-environmental field, outlined its applications, and mainly illustrated the progresses, status and inadequacies for the coupling research. Based on all the summaries, we proposed a new coupling method of physical mechanism and AI for reconstructing mechanism processes, followed by analyses of theoretical significance of partial parameters, feasibility of better generalization and interpretability, as well as prospection of imitating physical mechanism. At the end of the review, we discussed the trend of the coupling method of AI and eco-environment models.

Understanding the spatial connection between urban basic elements and pollutants in road-deposited sediment (RDS) is beneficial to the quantitative explanation of source areas and the precise management of urban nonpoint source pollution. The objective of this study was to explore the spatial connection between urban basic elements and nutrient contents in RDS, using Hanyang district of Wuhan city as a case study area. Total nitrogen (TN), total phosphorus (TP), exchangeable phosphorus (Ex-P), aluminum-bound phosphorus (Al-P), iron-bound phosphorus (Fe-P), occluded phosphorus (Oc-P), apatite phosphorus (Ca-P), detrital apatite phosphorus (De-P), and organophosphorus (Or-P) were chosen as representative pollutants, using the kernel density of the road network and seven groups of points of interest to represent the spatial distribution of urban basic elements. Through correlation analysis, the relationship between urban basic elements and nutrient contents in RDS was examined. The results showed that nutrient contents in RDS from Hanyang varied significantly with location. Specifically, Al-P, Oc-P, and Or-P had greater spatial variability in contrast with that of Ex-P and Fe-P, and the spatial variabilities of Ca-P and De-P both varied considerably with the particle size of the RDS. All types of urban basic elements and nutrient contents in RDS were correlated to different extents. Ex-P, Al-P, Oc-P, and Or-P were negatively correlated with the kernel density of most urban basic elements, whereas TN, TP, Fe-P, Ca-P, and De-P showed a positive correlation with the kernel density of most urban basic elements. TN, Al-P, Fe-P, Ca-P, and Or-P appeared to have much stronger correlation with the kernel density of urban basic elements compared to other selected pollutants, whereas the extent of correlation between them was influenced by the particle size of the RDS. In general, the correlation between nutrient contents in RDS and the kernel density of urban basic elements was more significant when the particle size of the RDS was under 450 μm and more robust when the particle size of the RDS was under 150 μm.

Scientific identification of runoff output characteristics of different land use patterns is the premise of controlling non-point source pollution in watersheds. The hydrology and output process of non-point source pollutants of forest, planting, and construction land with different rainfall characteristics were observed using a micro-watershed in a low mountain and hilly region of Southern China. The results showed that land use affected the hydrological characteristics and water quality processes of runoff. The characteristics of runoff generation time and cumulative rainfall under typical rainfall conditions were as follows:construction land(9 min, 2.0 mm), planting land(35 min, 11.4 mm), and forest land(108 min, 24 mm). There were significant differences in the three land use types in the pollution output process characteristics, such as pollutant concentration of total suspended matter(TSS), total nitrogen(TN) and phosphorus(TP), their components, N/P ratio change, and output intensity. Under typical rainfall, different land use types had similar pollution output stages, the mass concentrations of TSS, TN, and TP in the initial runoff were high, and then gradually stabilized. In addition, the first 30 min of the flow generation process contributed to the TSS, TN, and TP loads within the 23%-43% range. At the annual scale, there were significant differences between the contribution rate of each land use type to TN and TP load and ratio per unit area; the highest contribution to total pollution load was planting land(57% and 45%), while the highest in pollution load per unit area was construction land(9.50-12.50). The results also showed that the distribution of key non-point source areas had different spatial and temporal dynamics, which was comprehensively determined by the land use types in catchment units, the characteristics of annual rainfall, among other factors. With the increase in rainfall, the main contribution non-point source pollution in the micro-watershed changed from construction land to planting land. Targeted ecological interception strategies should be implemented based on the distribution characteristics of key source areas and characteristics of underlying surface runoff production process.

At present, there are few reports about how impervious surface microstructure characteristics affect the runoff output process of street dust. Based on field observations of 12 rainfall events, this study quantified the microstructure characteristics of impervious surfaces by structural depth (roughness) and analyzed the correlation between roughness and accumulation characteristics of street dust on sunny days as well as scouring characteristics in rainy days. The results show that the roughness of the underlying surface notably affects dust accumulation on sunny days and scouring in rainy days. The correlation between roughness and street dust accumulation ( r =0.664, P <0.01) was enhanced on sunny days, and the correlation between roughness and street dust erosion ( r =0.527, P <0.01) was enhanced by rainfall. The correlation of street dust accumulation and roughness of each particle size segment increased as particle size increased (0.529 ≤ r <0.757), and the correlation between street dust scouring amount and roughness decreased as particle size increased (0.603 > R > 0.209). By establishing the linear regression model of roughness and rainfall, the cumulative pollution load of TSS in rainfall runoff can be well predicted. The effects of roughness and rainfall on the cumulative load of grain sizes<20 μm and >250 μm are significant. These results elucidate the role of roughness and rainfall analysis in predicting surface runoff pollution load characteristics, which can provide new information for predicting and evaluating urban non-point source pollution.

The transport and retention of phosphorus is a key process in nutrient cycling in river ecosystems and one of the main indicators used to evaluate river health. To explore the effect of check dams on the transport and retention of phosphorus, water samples were collected from four representative monitoring sections of a check-dammed reach of the Qingshui River in Zhangjiakou City. Various forms of phosphorus and runoff process were monitored, and local real-time rainfall data were also collected. The results showed that:① The average concentration ratios of total phosphorus (TP), total dissolved phosphorus (TDP), total particulate phosphorus (TPP), and total suspended solids (TSS) downstream to upstream of the dam were 50%, 79%, 47%, and 58%, respectively, indicating that the check dam has a retention effect on phosphorus and sediment. ② During non-rainfall periods, TP, TDP, and TPP were retained in the check dam reach, while these forms of phosphorus were both retained and transported in the check dam reach during period of rainfall; the ratio of TP, TDP, and TPP retaining rainfall events to total rainfall events was 63.6%, 9%, and 81.8%, respectively, indicating that the transport-retention process was affected by the time interval, duration, and intensity of rainfall events. ③ When a single rainfall event or continuous event exceeded 56 mm, the retention effect of the check dam notably decreased.

Determining the influence of pervious/impervious underlying surface pattern (composition, position, proportion, etc.) on the generation capacity of surface runoff and pollution in the urban parcel-based catchment could aid in alleviating the urban waterlogging and control non-point source pollution significantly. Landscape metrics were used to analyze the relationship between the characteristics of pervious/impervious underlying surface pattern and total runoff ( Q ) and the cumulative load of dissolved pollutants ( L d ) and particulate pollutants ( L p ). The results showed that: ① For the metrics of fragmentation, the patch density (PD) was positively correlated with Q and L d . and largest patch index (LPI) was negatively correlated with them. Especially, the PD exhibited a significantly positive correlation with L d ( r =0.59, P <0.05, calculated in COD). However, the LPI exhibited a significantly negative correlation with L d ( r =-0.60, P <0.05, calculated in COD). ② For the metrics of complexity, landscape shape index (LSI) was positively correlated with Q and L p , and mean shape index (MSI) was negatively correlated with them. Especially, the LSI exhibited a significantly positive correlation with L p ( r =0.61, P <0.05, calculated in TP) significantly. However, the MSI exhibited a significantly negative correlation with L p ( r =-0.62, P <0.01, calculated in TP) significantly. ③ For the metrics of vergence, the split index (SPLIT) was positively correlated with Q and L d , and the cohesion index (COHESION) was negatively correlated with them. The COHESION exhibited a significantly negative correlation with L d ( r =-0.59, P <0.05, calculated in COD), whereas the SPLIT exhibited a significantly positive correlation with L d ( r =0.6, P <0.05, calculated in COD). ④ In the planning on the distribution and pattern of pervious surface under small-scale catchment, it is suggested that the scattered small-regular patches should be transformed to large-irregular patches or patch group. The relationship of the fragmentation, complexity, and vergence of pervious/impervious surface, with the runoff generation, and pollution output in parcel-based catchment was analyzed, which provided a new method for rainfall runoff and pollution control by considering rational allocation of LID facilities in terms of its pattern characteristics (area, distance, shape, etc.).

Most sponge city constructions in China are carried out in urban parcel-based catchments, and the quality and quantity of surface runoff can be controlled by several low impact development (LID) facilities. However, there are few reports on the generation and control of urban diffuse pollution. In this study, two areas with different hardening rates were compared to analyze the load conditions during the accumulation-wash-off-transport process of particulate pollutants. The results showed that the road surface in the catchment was the main underlying surface that the particulate pollutants contributed to. The road dust accumulation in the medium hardening rate (61.1%) and high hardening rate (73.6%) plots accounted for 88.4% (2.22-12.51 g ·m -2 ) and 90.1% (4.99-33.43 g ·m -2 ) of the catchment area unit, respectively. The contribution to the suspended solids (SS) load of runoff was 91.7% (0.97-7.34 g ·m -2 ) and 90.5% (0.92-18.77 g ·m -2 ), respectively. The SS load of road runoff accounted for approximately 95.2% and 83.1%, respectively. The pollution load (SS) after treatment by the LID facilities was approximately 24.0% and 40.2% of the surface runoff, respectively. The particle size distribution of road dust during the accumulation and wash-off processes was>150 μm, while that in surface and output runoff was <50 μm. With the increase in the impervious area, the distribution of finer particles (<105 μm) in the process of accumulation and wash-off increased (24.4%, 106.4%), while the distribution of particles <50 μm in road runoff decreased (12.4%). The particle size distribution of the accumulated, washed dust, and the rain runoff on the roof were roughly similar to those on the road. However, compared to the particle size distribution of road dust, in the accumulation and wash-off processes, the coarser particles (>1000 μm) of the medium hardening rate plot and the particles of size 250-450 μm and <45 μm of the high hardening rate plot increased significantly (>1000 μm: 58.1%, 108.5%; 250-450 μm: 72.9%, 41.8%; <45 μm: 59.2%, 64.8%). The results revealed the entire distribution process (accumulation-wash-off-transport) of particulate pollutants and the effect of LID facilities on the total SS pollution load of the catchment, which can provide an important reference for the scientific assessment of the project performance of LID installation in urban parcel-based catchments.

A comprehensive and scientific understanding of non-point source pollutant transport pathways and source apportionment in combined sewer systems is essential for managing and improving the urban water environment. This study analyzed build-up and wash-off processes of pollutants on road surfaces and in sewers within a catchment of combined sewer systems in a typical old district in Zhuhai. Besides, source apportionment of the entire urban non-point source pollution was investigated by using the mass conservation method. The outcomes revealed that the build-up load of road deposited sediments in the study area was (28.81±10.69) g·m -2 . The average wash-off load of road deposited sediments during five different rainfall events was (19.27±10.90) g·m -2 and the wash-off percentage was (52.69±13.3)%. The event mean concentrations of suspended solids (SS) in road runoff were 52-109 mg·L -1 , and the event mean concentrations of SS in sewer runoff were 68-158 mg·L -1 . Source apportionment analysis showed that road runoff, domestic wastewater, and sewer sediments contributed 39%-72%, <20%, and 13%-56% to SS, respectively. The thickness of sewer sediments increased by 1-14 cm during light and moderate rains, and the thickness decreased by 7-17 cm during heavy rains. It was found that rainfall characteristics affected the contribution percentages of pollution sources. The contribution of pollution from road runoff, domestic sewage, and sewer sediments in combined sewer systems were 2%-52%, 9%-65%, and 8%-81%, respectively. The derived outcomes should be useful for developing recommendations to control non-point source pollution in combined sewer systems and improve urban receiving water quality in China.

Different combinations of low impact development (LID) technologies can be applied for control of urban non-point source pollution. There are currently few evaluations of urban non-point source pollution and pollution load reduction based on a combination of porous asphalt and bio-retention. Taking Shenzhen International Low Carbon City as an example, road-deposited sediments were collected prior to and after rainfall events. Runoff was monitored under six typical rainfall events, from porous asphalt and the inlet/outlet of bio-retention. Through analysis of changes in the process of "build-up-wash-off-transport" of pollutant loads, the average build-up of road-deposited sediments in the study area was found to be (15.80±3.79) g·m -2 ; the mass percentage of road-deposited sediments (size>250 μm) was approximately 65.14%. The average wash-off percentage of six different intensity rainfall events was 17.15%, and road-deposited sediments (size<105 μm) were carried by 62.71%-74.94%. The average pollution loads of surface runoff pollutants SS, TN, and TP were 2.02, 0.025, and 0.0013 g·m -2 , respectively. The removal rates of SS, TN, and TP through porous asphalt under infiltration and filtration were 70.26%, 46.29%, and 19.27%, respectively. The secondary purification removal rates of runoff water in bio-retention were 85.25%, 20.22%, and 70.27%, respectively. Pollutant loads into Dingshan River totaled 0.08, 0.011, and 0.0003 g·m -2 , representing 4.05%, 43.47%, and 24.39% of runoff. The combination thus had a significant effect on runoff purification. Through quantitative research on the formation of non-point source pollution, this paper provides a scientific basis for estimating pollution loads of urban non-point source pollution and evaluating the performance of LID projects. It makes suggestions for the popularization and application of LID and sponge city design in China.

Social economy in Huaihe River Basin had undergone enormous changes during 1990-2010. The grain yield had increased by 58%, from 64.14 million tons to 101.21 million tons, and the urbanization rate had increased by 22%, from 13% to 35%. Assessing the negative impacts of these high intensive human activities caused by rapid social development on terrestrial ecosystem would serve as a scientific basis for quantitative management of regional ecology. This paper estimated the spatial and temporal distribution of net anthropogenic nitrogen input (NANI) in Huaihe River Basin during 1990-2010. The results showed that there was an increasing trend in NANI in the period of 1990-2001, and after that this trend was slower. The NANI increased from approximately 17232 kg N · km(-2) · a(-1) in 1990 to a peak of 28771 kg N · km(-2) · a(-1) in 2003, and then declined to 26415 kg N · km(-2) · a(-1) in 2010. Chemical fertilizer and atmospheric deposition were the largest two sources of NANI, followed by food & feed import and biological nitrogen. Contributions from both chemical fertilizer and atmospheric deposition had been increasing continuously, respectively from 64% and 16% in 1990 to 77% and 19%. Our findings implied that the shift from fertilizer-supported agriculture and fossil fuel-supported industry to sci-tech lead economic development is urgently needed.

Nitrogen (N) inputs caused by human activities potentially influences the aquatic environment. However, researches on N pollution in China are mainly discussed from the microscopic point of view, i. e. field experiment. Watershed-scale diagnosis of N pollution has just started, leading to ambiguous identification of ecological problems, pollution issues and pollution potential at watershed scale. In this paper, relationships between net anthropogenic N inputs (NANI) and riverine N flux (RNF) and factors influencing these relationships at watershed scale had been investigated. This would help diagnose ecological and environmental problems at watershed scale, understand the roles of natural climate and human activities in affecting N fluxes, and ultimately provide both theoretical and practical insights into environmental management decisions.

Road-deposited sediment (RDS) is an important carrier of the diffused pollution. This study analyzed the influences of the urban-suburban-rural gradient (central urban, urban village, central suburban county, rural town, and rural village areas) on the content and chemical fractions of heavy metals. The concentrations of five heavy metals (Cr, Cu, Ni, Pb, and Zn) in RDS in the central urban area were the highest, and the lowest concentrations appeared in the rural village area. The mass of RDS per unit area were opposite to the metals concentrations in distribution. The proportion of weak acid extractable Ni, Pb, and Zn in RDS was higher than that of Cr and Cu. The contribution of heavy metals in smaller grain size (32.4% - 62.4%) was greater than that in coarser grain size (22.9% - 49.6%). It will be helpful to reduce the RDS pollution for runoff and apply appropriate strategies for controlling runoff pollution from RDS according to RDS and its contribution to heavy metal pollution along the urban-rural gradient.

The heavy metal pollution in runoff caused by street dust washoff has been an increasingly prominent problem in the context of rapid urbanization in China. Based on measurement of heavy metal contents in street dusts with different particle sizes and an experiment of street dust washoff using simulated rainfall, we analyzed the role of particle size of street dust in heavy metal pollution, and the variation in geometrical forms of heavy metals during street dust washoff. Our results showed that the heavy metal concentration decreased from "static" street dust to "dynamic" runoff particulate in the same diameter particles. Heavy metals in street dust were dissolved and extracted during washoff. The average loss proportion of the five metals (Cr, Cu, Ni, Pb, Zn) were 24.3%, 56.8%, 34.3%, 22.8%, 27.3%, respectively. The loss proportion increased with the decrease of the particle size of street dust. Proportion of extracted form dust was higher in street than that in washoff samples, which suggested some dissolved loss in water. In washoff samples, dissolved metals of waterphase did not have significant changes; however, heavy metals with particle state in waterphase reduced rapidly during runoff. Meanwhile, heavy metals of solid-phase particle reduced during runoff. Street dust with small particle size had higher loss rate during runoff. The variation rate of street dust loss among different particle sizes varied from 4.6% to 62.1%. Street dust with smaller particle size had higher migration ability in runoff, which was more risky to urban water pollution.