Characterization of surface runoff in urban areas

2002 ◽  
Vol 45 (9) ◽  
pp. 249-254 ◽  
Author(s):  
J.S. Choe ◽  
K.W. Bang ◽  
J.H. Lee

Water quality measurements of surface runoff have been carried out in selected residential and industrial zones in urban areas, in which yearly mean precipitation is 1,225 mm. The concentrations of constituents in the surface runoff were measured at sampling sites categorized by land use type in the residential zone, and by industry type in the industrial zone. The water quality constituents of BOD5, COD, SS, NO3-N, TKN, PO4-P, TP, n-Hexane extracts, Cr, Cu, Pb and Fe were analyzed. The event mean concentrations (EMCs) of COD, SS, TKN and TP in the residential zone were 313 mg/L, 279 mg/L, 8.45 mg/L, 1.98 mg/L, and those in the industrial zone were 80 mg/L, 106 mg/L, 5.07 mg/L, and 1.93 mg/L, respectively. Cumulative load curves were created to analyze the first-flushing effect of each pollutant related to the pollutant, the rainfall event, and the land use type. No general relationship between the cumulative load and runoff has been established. The degree of first-flushing effect by constituents was in the following order; TKN>COD>SS>HEM>TP>PO4-P. The correlations between SS and other constituents were analyzed to evaluate the efficiency of the physical treatment process to control the surface runoff in urban areas. Based on the correlation of constituents with SS, high treatment efficiency of SS, heavy metals, organic matter, and TP was expected. The unit pollutant loading rates of COD, SS, TKN, TP, Cr and Pb in the residential zone were 2,392, 2,130, 64.6, 15.1, 0.31, and 1.83 kg/ha/yr, and those in the industrial zone were 612, 812, 38.7, 14.8, 0.51 and 0.82 kg/ha/yr, respectively.

2013 ◽  
Vol 8 (1) ◽  
pp. 084596 ◽  
Author(s):  
Zhongchang Sun ◽  
Xinwu Li ◽  
Wenxue Fu ◽  
Yingkui Li ◽  
Dongsheng Tang

2020 ◽  
Author(s):  
Long Ho ◽  
Ruben Jerves-Cobo ◽  
Matti Barthel ◽  
Johan Six ◽  
Samuel Bode ◽  
...  

Abstract. Rivers act as a natural source of greenhouse gases (GHGs) that can be released from the metabolisms of aquatic organisms. Anthropogenic activities can largely alter the chemical composition and microbial communities of rivers, consequently affecting their GHG emissions. To investigate these impacts, we assessed the emissions of CO2, CH4, and N2O from Cuenca urban river system (Ecuador). High variation of the emissions was found among river tributaries that mainly depended on water quality and neighboring landscapes. By using Prati and Oregon Indexes, a clear pattern was observed between water quality and GHG emissions in which the more polluted the sites were, the higher were their emissions. When river water quality deteriorated from acceptable to very heavily polluted, their global warming potential (GWP) increased by ten times. Compared to the average estimated emissions from global streams, rivers with polluted water released almost double the estimated GWP while the proportion increased to ten times for very heavily polluted rivers. Conversely, the GWP of good-water-quality rivers was half of the estimated GWP. Furthermore, surrounding land-use types, i.e. urban, roads, and agriculture, significantly affected the river emissions. The GWP of the sites close to urban areas was four time higher than the GWP of the nature sites while this proportion for the sites close to roads or agricultural areas was triple and double, respectively. Lastly, by applying random forests, we identified dissolved oxygen, ammonium, and flow characteristics as the main important factors to the emissions. Conversely, low impact of organic matter and nitrate concentration suggested a higher role of nitrification than denitrification in producing N2O. These results highlighted the impacts of land-use types on the river emissions via water contamination by sewage discharges and surface runoff. Hence, to estimate of the emissions from global streams, both their quantity and water quality should be included.


Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 729
Author(s):  
Siru Wang ◽  
Pinzeng Rao ◽  
Dawen Yang ◽  
Lihua Tang

Water pollution poses threats to urban environments and subsequently impacts the ecological health and sustainable development of urban areas. Identifying the spatiotemporal variation in non-point sources (NPS) pollution is a prerequisite for improving water quality. This paper aimed to assess the NPS pollution load and then recognized the spatiotemporal characteristics of the pollution sources in a typical urbanized area. A combination model based on land use type was used to simulate the NPS pollution load. The results showed the following: (1) ponds and farmlands had higher pollution production intensities than other land use types, but the intensity and magnitude of pollution emissions were generally greater in urban areas; (2) monthly and annual total nitrogen (TN) and total phosphorus (TP) emissions had the same pattern as rainfall, and TN and TP emissions accounted for 56.2% and 58.0%, respectively, of the total in summer; (3) TN pollution was more serious than TP pollution in the study area, especially in farmlands; (4) urban runoff (UR) and livestock and poultry breeding (LPB) were the main sources of NPS, TN and TP emissions in the study area. If these NPS pollutants cannot be removed from this area, a large amount of freshwater is needed to dilute the current rivers to meet the requirement of the fourth category of China national environmental quality standards for surface water. This problem is serious in the control of polluted rivers in many cities throughout China.


2015 ◽  
Vol 19 (10) ◽  
pp. 4215-4228 ◽  
Author(s):  
P. Tokarczyk ◽  
J. P. Leitao ◽  
J. Rieckermann ◽  
K. Schindler ◽  
F. Blumensaat

Abstract. Modelling rainfall–runoff in urban areas is increasingly applied to support flood risk assessment, particularly against the background of a changing climate and an increasing urbanization. These models typically rely on high-quality data for rainfall and surface characteristics of the catchment area as model input. While recent research in urban drainage has been focusing on providing spatially detailed rainfall data, the technological advances in remote sensing that ease the acquisition of detailed land-use information are less prominently discussed within the community. The relevance of such methods increases as in many parts of the globe, accurate land-use information is generally lacking, because detailed image data are often unavailable. Modern unmanned aerial vehicles (UAVs) allow one to acquire high-resolution images on a local level at comparably lower cost, performing on-demand repetitive measurements and obtaining a degree of detail tailored for the purpose of the study. In this study, we investigate for the first time the possibility of deriving high-resolution imperviousness maps for urban areas from UAV imagery and of using this information as input for urban drainage models. To do so, an automatic processing pipeline with a modern classification method is proposed and evaluated in a state-of-the-art urban drainage modelling exercise. In a real-life case study (Lucerne, Switzerland), we compare imperviousness maps generated using a fixed-wing consumer micro-UAV and standard large-format aerial images acquired by the Swiss national mapping agency (swisstopo). After assessing their overall accuracy, we perform an end-to-end comparison, in which they are used as an input for an urban drainage model. Then, we evaluate the influence which different image data sources and their processing methods have on hydrological and hydraulic model performance. We analyse the surface runoff of the 307 individual subcatchments regarding relevant attributes, such as peak runoff and runoff volume. Finally, we evaluate the model's channel flow prediction performance through a cross-comparison with reference flow measured at the catchment outlet. We show that imperviousness maps generated from UAV images processed with modern classification methods achieve an accuracy comparable to standard, off-the-shelf aerial imagery. In the examined case study, we find that the different imperviousness maps only have a limited influence on predicted surface runoff and pipe flows, when traditional workflows are used. We expect that they will have a substantial influence when more detailed modelling approaches are employed to characterize land use and to predict surface runoff. We conclude that UAV imagery represents a valuable alternative data source for urban drainage model applications due to the possibility of flexibly acquiring up-to-date aerial images at a quality compared with off-the-shelf image products and a competitive price at the same time. We believe that in the future, urban drainage models representing a higher degree of spatial detail will fully benefit from the strengths of UAV imagery.


2020 ◽  
Vol 12 (2) ◽  
pp. 84-107
Author(s):  
Bismark Mensah ◽  
Isaac Obeng Darkwa ◽  
Esther Yamoaba Bonful ◽  
Moses Bangfunourteru Tuu ◽  
Mohammed Sanda ◽  
...  

Ghana is rapidly urbanizing. This urbanization has resulted in villages growing into towns and towns into urbanized areas. Theories and models have been employed to explain the internal structure of urban areas, especially, with respect to land use variations. These models started with the classical urban land use models in America. Urban scholars in Africa have struggled to fit the development of the African cities into these classical models. They have therefore called for African scholars to develop models for urban land use in Africa. This paper sought to identify the common patterns of land use activities which shape the internal structure of Ghana’s secondary cities. The study employed Geographic Information System (GIS) as a major tool of analysis in explaining the patterns in urban areas. This is augmented with in-depth ground observations of the study areas. The findings of the study showed the absence of homogeneity in most of the sectors and undefined industrial zones as contradictions to the classical models. The study further revealed that residential zones were not fully occupied by either lower income, middle income, or higher income residence. The income groups may only dominate in a given sector. Based on the findings, a common pattern is proposed to represent the land uses within the selected secondary cities in Ghana.


Author(s):  
Elisa Flávia Luiz Cardoso Bailão ◽  
Leovigildo Aparecido Costa Santos ◽  
Sara Dos Santos Almeida ◽  
Patrícia Lima D’Abadia ◽  
Ronny José de Morais ◽  
...  

Low-order streams located near urban areas usually receive domestic, industrial, and agricultural wastewaters that negatively affect river water quality. Additionally, water pollution is associated with land-use variations around the river, which is characterized by unplanned urbanization, intense agricultural activities, and deforestation. This work correlated land-use patterns with physicochemical quality and genotoxic potential of water at four points (P1 to P4) along the Extrema River, located in an industrial and agricultural area of Central Brazil. Physicochemical analyses indicated that the water collected from the Extrema River is inappropriate for human consumption. Using the Allium cepa model, no evidence of cytotoxicity was observed at any point; in contrast, the genotoxic potential of these water samples was observed. The correlation of these results with land use showed that the water collected at P3 was the most contaminated; this is probably due to the inflow of wastewater from municipal, industrial, and agriculture activities. Different results were observed for P2 and P4, where land-use analysis attributed the water quality to forest burns. We concluded that differential use of the land changed the characteristics of the associated river water, and A. cepa parameters were more related to land-use characteristics than to physicochemical parameters. This study highlighted the importance of associating land use with the cyto genotoxic potential of water.


2013 ◽  
Vol 16 (1) ◽  
pp. 114-129 ◽  
Author(s):  
Haijun Wang ◽  
Wenting Zhang ◽  
Song Hong ◽  
Yanhua Zhuang ◽  
Hongyan Lin ◽  
...  

Non-point source (NPS) pollution has become the major reason for water quality deterioration. Due to the differences in the generation and transportation mechanisms between urban areas and rural areas, different models are needed in rural and urban places. Since land use has been rapidly changing, it is difficult to define the study area as city or country absolutely and the complex NPS pollution in these urban–rural mixed places are difficult to evaluate using an urban or rural model. To address this issue, a fuzzy system-based approach of modeling complex NPS pollutant is proposed concerning the fuzziness of each land use and the ratio of belonging to an urban or rural place. The characteristic of land use, impact of city center and traffic condition were used to describe spatial membership of belonging to an urban or rural place. According to the spatial membership of belonging to an urban or rural place, the NPS distributions calculated by the urban model and rural model respectively were combined. To validate the method, Donghu Lake, which is undergoing rapid urbanization, was selected as the case study area. The results showed that the urban NPS pollutant load was significantly higher than that of the rural area. The land usage influenced the pollution more than other factors such as slope or precipitation. It also suggested that the impact of the urbanization process on water quality is noteworthy.


1999 ◽  
Vol 39 (12) ◽  
pp. 93-98
Author(s):  
Osami Kawara ◽  
Manabu Uehara ◽  
Kanako Ibaragi

The important non-point sources in Japan are urban areas, rice paddy fields and forest. The forest area in river basins occupies about 70 per cent. Furthermore, Japanese forest is usually on steep mountains. Therefore, pollutant loads from the forest cannot be ignored in Japan. In this study, we discuss the seasonal variations of water quality of runoff from forest, and of component runoffs, inter-surface runoff and groundwater runoff, based on observations and on the results separated by a numerical filter. The seasonal variations of water quality and four types of relations between water quality and flow rates of component runoffs were noted.


2007 ◽  
Vol 38 (2) ◽  
pp. 125-138 ◽  
Author(s):  
Evelyn Uuemaa ◽  
Jüri Roosaare ◽  
Ülo Mander

We investigated the relationship between land use parameters and FRAGSTATS-based landscape metrics (Edge Density, Patch Density, Mean Shape Index, Mean Euclidean Nearest Neighbour Index, Contagion, Patch Richness Density and Shannon's Diversity Index) and nutrient/organic-matter-based water quality indicators (BOD7 and CODKMnO4 values, total-N and total-P concentrations in water) in 24 catchments with various land use patterns in Estonia, using the CORINE Land Cover Map (1:100 000). Multiple regression analysis showed that, for BOD7, total-N and total-P, the most important predictor was the proportion of urban areas, but landscape metrics also had a significant relationship with water quality. Mean Shape Index and Contagion were the most important predictors for CODKMnO4. The knowledge that land use and landscape configuration impact water quality can be used in establishing and implementing water management plans in Europe.


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