Water Bodies In Urban Areas Research Articles

How does urban form explain water cooling effect heterogeneity: A case study in Wuhan, China

Water bodies in urban areas are considered to be natural and effective cooling factors that can help mitigate the urban heat island (UHI) effect. Previous studies highlighted the cooling effect is determined by the size and landscape of the water bodies. However, it is unclear how the urban form surrounding water bodies influences the water cooling effect received by human activity space. Using high resolution data and a multiple linear regression model, the effect of various 2D/3D urban form factors on the average water cooling intensity (AWCI) and water cooling intensity (WCI) at the fine scale were examined in Wuhan City on hot days. We further verified the spatial heterogeneity of the relationship between urban form factors and WCI according to the distance to and size of adjacent water bodies. The AWCI of the entire surrounding area were correlated with building morphology indicators. Urban form indicators effectively explained the variations of WCI at the fine scale, indicating that a mixture of large building volume density (BVD) with small building density (BD), and an aggregated impervious surface area (ISA) with a complex shape were conducive to WCI. Additionally, building morphology had a larger impact on the cooling effect around small water bodies and in the outer buffer area of water bodies. In comparison, the cooling effect of the area surrounding large water bodies was more affected by the landscape of the ISA. We therefore propose a differentiated urban planning strategy to take full use of the limited water cooling effect.

Assessing the Impact of Sachet Water Disposal Practices on Urban Environmental Health in Southern Nigeria

This research investigated the impact of sachet water disposal practices on the environmental health of urban Nigeria. The study used both practice and scientific data collection to gather survey, water, and disease check information. The data was analyzed using SPSS. The results showed that 85% of waste in sachet water was unsanitarily disposed of, with 40% dumped on the streets and 25% dumped in drainage systems. The pollution of water bodies in urban areas was alarming, with plastic levels ranging from 10 mg to 150 mg per liter. High waste areas also showed increased incidence rates of waterborne diseases, such as typhoid (15%), cholera (12%), dysentery (8%), and hepatitis A (5%). The population's knowledge of proper disposal methods was generally low, with 25% fully aware, 20% knowing the right method but not using it, 30% having minimal understanding, and 25% having no knowledge at all. The study found that improper disposal rates had decreased from 70% in 2020 to a projected 50% in 2024. However, further improvement is needed in waste management infrastructure, laws and penalties, public awareness, and encouraging responsible and sustainable waste disposal practices.

Change Detection Using Multispectral Satellite Images for Sustainable Development in Regions of Al-Najaf Al-Ashraf, Iraq

The change detection in urban and surrounding areas, such as vegetation and bare, is a significant achievement for sustainable development, especially nowadays. The research conducted a supervisor classification of two images representing two time periods (1973 and 2023) using the method of land cover and land use (LCLU) using the ArcGIS 10.8.2 program. The classified pixels were converted into digital data to compare using the land cover method and land use change (LCLUG). The results showed a significant expansion in the urban areas of Najaf and Kufa districts, 5.72 km2 to 134.95 km2, with a decrease in the area of green areas, 17.26 km2 to 15.16 km2, and the absence of water areas, in addition to the transformation of most of the barren areas to urban areas 215.64 km2 to 88.51 km2, The study concluded that there was a significant decrease in the area of green areas in the study area and the absence of water bodies in urban areas, and these two indicators - along with the increase in urban areas - harm the environment of the region and the quality of environmental influences on the lives of the people who live in it. Which negatively affects its sustainable development plans.

Analysis of heavy metals and pathogen levels in vegetables cultivated using selected water bodies in urban areas of the Greater Accra Metropolis of Ghana

Open-surfaced water sources have been used to irrigate vegetable farms in cities. Open-surface water often contains unmonitored concentrations of health-threatening contaminants that pose health risks, especially when used to produce vegetables for human consumption. However, information on levels of heavy metals and faecal coliform bacteria in such vegetables in selected sites, especially in Greater Accra Metropolitan Area (GAMA) of Ghana is rare. This study examines the levels of heavy metals and faecal coliform in two vegetables-lettuce and bell pepper - that were cultivated using open-surface wastewater from drains and constructed reservoirs at different locations of the GAMA. Using concurrent mixed methods, questionnaires were administered to 67 vegetable farmers, followed by the collection of vegetable samples from three urban farm sites, Haatso and Dzorwulu and Weija irrigation scheme site (WISS) for laboratory analysis. The concentrations of Lead (Pb), Mercury (Hg) and Cadmium (Cd) were determined using atomic absorption spectroscopy after microwave digestion of the vegetables while total faecal coliform was quantified using MacConkey-Endo broth method. The results from all three sites showed that the concentrations of Cd (=0.001 μg/mg) and Pb (=0.005 μg/mg) in lettuce were within the World Health Organization's (WHO) permissible levels. However, the Hg (≥0.309 μg/mg) and faecal coliform (>5 count/100 ml) in the vegetables from all three sites exceeded the WHO permissible limits. Therefore, consumers of vegetables from such urban farms are exposed to health risks associated with Hg and faecal coliforms. There is the need to intensify education on the health risks of consuming vegetables produced from open-surface water sources from the observed sites. The enforcement of existing phytosanitary standards to enhance food safety and the quality of urban vegetables is also recommended.

Application of bathymetry in water bodies in urban areas of the five Brazilian regions

Application of bathymetry in water bodies in urban areas of the five Brazilian regions

A Comparison of Different Water Indices and Band Downscaling Methods for Water Bodies Mapping from Sentinel-2 Imagery at 10-M Resolution

Satellite-based remote sensing is important for monitoring the spatial distribution of water resources. The water index is currently one of the most widely used water body extraction methods. Based on Sentinel-2 remote sensing image, this study combines area-to-point regression kriging interpolation, bilinear interpolation, and the Gram–Schmidt (GS) pan-sharpening method with the water indices MNDWI, AWEIsh and WI2015 to compare different water body extraction methods. The experimental results showed that all water indices have satisfactory extraction ability, with the kappa coefficient as an accuracy threshold above 0.8. Moreover, the GS downscaling method combined with the WI2015 yielded the best performance. This research demonstrates the efficacy of the WI2015 method to extract water bodies in urban areas and its ability to comprehensively describe river water bodies. The findings indicate that high-resolution band information is particularly important for improving low-resolution band downscaling results and can significantly minimize erroneous water body extraction.

Energetics of Urban Canopies: A Meteorological Perspective

The urban climatology consists not only of the urban canopy temperature but also of wind regime and boundary layer evolution among other secondary variables. The energetic input and response of urbanized areas is rather different to rural or forest areas. In this paper, we outline the physical characteristics of the urban canopy that make its energy balance depart from that of vegetated areas and change local climatology. Among the several canopy characteristics, we focus on the aspect ratio h/d and its effects. The literature and methods of retrieving meteorological quantities in urban areas are reviewed and a number of physical analyzes from conceptual or numerical models are presented. In particular, the existence of a maximum value for the urban heat island intensity is discussed comprehensively. Changes in the local flow and boundary layer evolution due to urbanization are also discussed. The presence of vegetation and water bodies in urban areas are reviewed. The main conclusions are as follows: for increasing h/d, the urban heat island intensity is likely to attain a peak around h/d≈4 and decrease for h/d>4; the temperature at the pedestrian level follows similar behavior; the urban boundary layer grows slowly, which in combination with low wind, can worsen pollution dispersion.

Quantifying the Cooling Effect and Scale of Large Inner-City Lakes Based on Landscape Patterns: A Case Study of Hangzhou and Nanjing

The rapid urbanization worldwide has brought various environmental problems. The urban heat island (UHI) phenomenon is one of the most concerning issues because of its strong relation with daily lives. Water bodies are generally considered a vital resource to relieve the UHI. In this context, it is critical to develop a method for measuring the cooling effect and scale of water bodies in urban areas. In this study, West Lake and Xuanwu Lake, two famous natural inner-city lakes, are selected as the measuring targets. The scatter plot and multiple linear regression model were employed to detect the relationship between the distance to the lake and land surface temperature based on Landsat 8 Operational Land Imager/Thermal Infrared Sensor (OLI/TIRS) and Sentinel-2 data. The results show that West Lake and Xuanwu Lake massively reduced the land surface temperature within a few hundred meters (471 m for West Lake and 336 m for Xuanwu Lake) and have potential cooling effects within thousands of meters (2900 m for West Lake and 3700 m for Xuanwu Lake). The results provide insights for urban planners to manage tradeoffs between the large lake design in urban areas and the cooling effect demands.

Spatio-Temporal Relationship between Land Cover and Land Surface Temperature in Urban Areas: A Case Study in Geneva and Paris

Currently, more than half of the world’s population lives in cities, which leads to major changes in land use and land surface temperature (LST). The associated urban heat island (UHI) effects have multiple impacts on energy consumption and human health. A better understanding of how different land covers affect LST is necessary for mitigating adverse impacts, and supporting urban planning and public health management. This study explores a distance-based, a grid-based and a point-based analysis to investigate the influence of impervious surfaces, green area and waterbodies on LST, from large (distance and grid based analysis with 400 m grids) to smaller (point based analysis with 30 m grids) scale in the two mid-latitude cities of Paris and Geneva. The results at large scale confirm that the highest LST was observed in the city centers. A significantly positive correlation was observed between LST and impervious surface density. An anticorrelation between LST and green area density was observed in Paris. The spatial lag model was used to explore the spatial correlation among LST, NDBI, NDVI and MNDWI on a smaller scale. Inverse correlations between LST and NDVI and MNDWI, respectively, were observed. We conclude that waterbodies display the greatest mitigation on LST and UHI effects both on the large and smaller scale. Green areas play an important role in cooling effects on the smaller scale. An increase of evenly distributed green area and waterbodies in urban areas is suggested to lower LST and mitigate UHI effects.

Use of concrete mats to protect slopes of water bodies in urban areas

Plots of land located in close proximity to the boundaries of the water body within the city limits are used both for recreational purposes and participate in the creation of a favorable comfortable urban environment. Since the banks of water bodies are subject to change as a result of the influence of natural factors and human activity, the construction of a shore protection system is required to protect them. A study of the structural solutions of shoreline anchorages in urban areas showed that the use of concrete mats for these purposes is most appropriate. The analysis included a comparison of the strengths and weaknesses of the existing and considered design solutions of hydraulic structures included in the urban environment improvement complex. Considerable attention is also paid to assessing the qualitative and quantitative volume of contaminants entering the water body during the construction of a shore–protecting hydraulic structure. In order to solve this problem, laboratory studies were performed simulating the process of concreting mats. The studies shows that concrete mats are a “clean coastal protection technology” compared to traditional technical solutions.

Flood vulnerability and coping mechanisms around the Weija Dam near Accra, Ghana

This paper argues that flood vulnerability around the Weija Dam, near Accra, the capital of Ghana, can be explained by the city’s complex peri-urbanization trajectories. The dam, which was constructed 40 years ago, supplies water to many parts of the Greater Accra Metropolitan Area. To offset the impacts of potential dam failure due to seismic activities, as well as accidental and planned water spillages, about 100 m of lands around the dam and 30 m of riparian lands around River Densu were reserved. Despite planning prohibitions, these reservations have largely been encroached by homebuilders and business operators. Analyses of time-series rainfall data and hazard mapping showed that during periods of torrential rainfall, the dam and the river are overwhelmed with storm water hence exposing the Weija Township located downstream to flood hazards. Questionnaire surveys, in-depth interviews with selected homebuilders, and institutional consultations revealed that the spatial and institutional management dynamics, customary land ownership, along with the growing defiance of planning regulations were the key influences of floods in the Weija Township. The affected households have attempted to mitigate the effects of flooding by elevating structures with stones and sandbags, strengthening walls, constructing drains and pumping water out during flooding events, but with little success. However, given the lack of political will to remove the unauthorized structures constructed within the buffers and reservations, the challenge now is to minimize flood vulnerabilities by flood-proofing buildings, improving drains and channelizing portions of the river within the township. These structural measures should be complemented by flood vulnerability maps, early flood warning and evacuation systems, mandatory property insurance policies, and above all, improved institutional coordination and collaboration for flood management. The paper recommends a re-examination of Ghana’s urban land use planning and management of water bodies in urban areas.

Water Bodies as a Catalyst to Growth and Development- The Case of Kodungallur Town, Kerala

The evolution and growth of cities and towns are primarily dependent on three important factors- Its geographic location, physical environment and its socio-economic environment. The presence of water in various forms in its natural setting plays an important role in enhancing the quality of physical environment and the socio-economic environment. During the processes of growth and expansion of cities and towns, the location of water bodies are seen by the planners and policy makers as liability and constrain rather than an asset or a resource. The development projects very often ignore the conservation of water bodies and transform them into other developments. Hence, the preservation, conservation and rejuvenation of water bodies in urban areas are important. The major factor that contributes to the sustainable development of an area is its water bodies. Moreover, presence of water bodies give added social, psychological and environment value. It includes (a) enhancing the aesthetic quality and place quality, thereby contributing to the image of the city or town (b)enhancing the social and recreational value and thus increasing the livability of the residents and land value many fold.In this paper the authors have made an attempt to (a) bring the importance of water bodies in an urban area to sustain its eco system (b) bringthe different ways by which the water bodies have acted as a catalyst to the growth and development of the town and (c) highlight the issues and potentials of the existing water bodies and (d) formulate strategies for sustainable development of town. These aspects are covered, in relation to a case study area Kodungallur town in Kerala State. In brief, the Kodungallur town is a culturally rich historical temple town of central Kerala. The town has its unique geographical advantage, historical and cultural importance and immense potential for growth and development.

Experimental Study on the Influence of Urban Water Body on Thermal Environment at Outdoor Scale Model

Urban Heat Island (UHI) has become a common urban problem that may lead to human health issues and increase in air-conditioning energy demand due to increase of air temperature. In order to reduce the UHI effect and improve the outdoor thermal environment is necessary to assess the effect of various measures. Water bodies’ ability to regulate the microclimate arguably has the potential to mitigate the effect. Water bodies commonly found in urban area are usually described as a permanent or temporary collection of water in form of small stationary water or pond. These water bodies contribute to altering the surrounding thermal environment due to its cooling effect, either by evaporation or transfer of heat between air and the water. In real urban condition, however, the heterogeneity makes it difficult to assess the cooling benefits and to isolate the effects of individual parameter (such as shape, surface area, wind condition or solar radiation) under the complex physic process involved in the urban meteorology. As an alternative method, an outdoor measurement on a physically reduced scale model was conducted in summer. The outdoor-scaled model consists of an array of 1.5m concrete cubes and able to recreate thermal pattern similar to the actual urban condition. A typical of commonly found water bodies in urban areas, pond, was installed in the scale model to have a better understanding on potential benefits of water bodies in urban area. In this paper, the author present initial findings on the characteristic of surrounding microclimate and its influential factors, particularly ambient air temperature near urban water body derived from the proposed approach. The experiment result shows interesting patterns, which generally shows cooling effect during the day and even though is limited it also happen during the night. Moreover, the present of more solar radiation and low wind conditions are found further enhance the cooling effect.

Adsorption of pathogenic microorganisms, NH4+ and heavy metals from wastewater by clinoptilolite using bed laminar flow

AbstractThe contamination of water bodies in urban areas is a serious problem, which may increase when wastewater is discharged without complete remediation. Due to their high adsorption capacity and ion-exchange properties, zeolites, such as clinoptilolite, can be used successfully to detoxify the wastewater before discharging it into the water body. In this study, experimental use of clinoptilolite is presented for water remediation. A static flow (A) and a laminar flow (B) method were applied in order to evaluate the efficiency of clinoptilolite for reducing different contaminants in the outflow wastewater of an old municipal treatment plant in Bologna District (Northern Italy). Mesocosm experiments were performed in order to achieve reduction of the microbial faecal indicators and of the excess nutrients and heavy metals in the effluent. During the experiments, pathogenic microorganisms, ammonium and heavy metals were reduced by as much as between 78 and 95% within 24 h, highlighting the great efficiency of this low-cost material for water remediation.

Assessment of Toxic Metal Contamination of Bottom Sediments in Water Bodies in Urban Areas

A study was carried out on 20 water bodies of the same origin in southern Poland. The study objectives included the assessment of toxic metal contamination in the bottom sediments of the water bodies in comparison with the geochemical background and sediments found in the substrate (i.e., vicinity) of the water bodies (i.e., the formations present in the surroundings of the water body itself), thus demonstrating the scale of anthropogenic enrichment of bottom sediments with toxic metals and assessing the cumulative impact on water bodies. The following amounts of toxic metals were found in the bottom sediments of the water bodies examined: 181.7–35200.0 ppm for zinc, 33.3–1648.8 ppm for lead, 1.8–359 ppm for cadmium, 14.0–271.5 ppm for copper, 45.3–167.5 ppm for chromium, and 12–128.5 ppm for nickel. Ratios of the values measured to the geochemical background were as follows: 0.7–135.9 (Zn), 0.6–53.0 (Pb), 0.7–143.6 (Cd), 0.9–18.1 (Cu), 5.0–18.6 (Cr), 1.1–11.7 (Ni).

Water Quality Criteria for Water Bodies in Urban Areas and Accompanying Changes in Surrounding and <i>In-Situ</i> Vegetation: Considerations from the Landscape Aspect of Planning Water Recreational Areas

Water bodies in urban areas are important as recreational areas. Thus, management plans that maintain high water quality are quite important. At the Hatadate Water Park adjacent to Miyagi University, water quality parameters such as visibility, COD, TOC, and TN were monitored at a small pond and the inflowing stream from August to December in 2011, and photographs were taken of these sites. Variations in COD and TOC were highly related to changes in the physical appearance, especially changes in vegetation. These findings suggest: 1) the importance of management of vegetation for water quality control; and 2) the importance of collecting photographic records of sites for research purposes of interpreting data and even as a data point of water quality. Together with the water quality goals for water bodies in urban areas proposed by Sudo et al. [1], these water quality criteria were assessed, and it was notable that COD often exceeded the set goal. These results suggest that the maintenance of vegetation is more important than controlling incoming TN for primary production in the pond. Seasonal variations in COD and TOC were plotted for surface water of Kamafusa and Okura dams, both are important lakes in Miyagi area and the catchments of both lakes are mainly hilly area, using published water quality reports. Similar annual-cycle changing patterns were shown both for the dams, implying that some kinds of ecological factors in the catchments are affecting the water qualities of the dam, even at those larger scale water bodies. Finally, by shifting the focus from only water to upstream features such as small park, or pocket park, with a parking lot for the water body, the importance of landscape including vegetation and tree cover was highlighted.

Anopheles gambiae distribution and insecticide resistance in the cities of Douala and Yaoundé (Cameroon): influence of urban agriculture and pollution.

BackgroundUrban malaria is becoming a major health priority across Africa. A study was undertaken to assess the importance of urban pollution and agriculture practice on the distribution and susceptibility to insecticide of malaria vectors in the two main cities in Cameroon.MethodsAnopheline larval breeding sites were surveyed and water samples analysed monthly from October 2009 to December 2010. Parameters analysed included turbidity, pH, temperature, conductivity, sulfates, phosphates, nitrates, nitrites, ammonia, aluminium, alkalinity, iron, potassium, manganese, magnesium, magnesium hardness and total hardness. Characteristics of water bodies in urban areas were compared to rural areas and between urban sites. The level of susceptibility of Anopheles gambiae to 4% DDT, 0.75% permethrin, 0.05% deltamethrin, 0.1% bendiocarb and 5% malathion were compared between mosquitoes collected from polluted, non polluted and cultivated areas.ResultsA total of 1,546 breeding sites, 690 in Yaoundé and 856 in Douala, were sampled in the course of the study. Almost all measured parameters had a concentration of 2- to 100-fold higher in urban compare to rural breeding sites. No resistance to malathion was detected, but bendiocarb resistance was present in Yaounde. Very low mortality rates were observed following DDT or permethrin exposure, associated with high kdr frequencies. Mosquitoes collected in cultivated areas, exhibited the highest resistant levels. There was little difference in insecticide resistance or kdr allele frequency in mosquitoes collected from polluted versus non-polluted sites.ConclusionThe data confirm high selection pressure on mosquitoes originating from urban areas and suggest urban agriculture rather than pollution as the major factor driving resistance to insecticide.

Urban drainage systems: An undervalued habitat for aquatic macroinvertebrates

Knowledge about the ecology of urban water systems is very scarce. We assessed the conservation value of urban drainage systems in lowland areas and compared these with similar watercourses in rural areas. A total of 36 water bodies in urban areas were selected to investigate the macroinvertebrate biodiversity in relation to environmental variables. Multivariate analysis of aquatic macroinvertebrate assemblages was used to distinguish urban water types and to link these types to key environmental variables. Several biodiversity indices for urban water systems were compared with those for other drainage systems in The Netherlands. Four types of macroinvertebrate assemblages were distinguished in the urban water systems, differing in environmental conditions and values of ecological indicators. The variation in macroinvertebrate assemblages was significantly explained by nitrate, pH, grain size (sediment composition), transparency, nymphaeid and submerged vegetation. Urban drainage systems can sustain a macroinvertebrate biodiversity comparable to that of drainage systems in rural areas (ditches and canals) and (semi)natural watercourses (lotic waters such as small streams and rivulets) and can even be a habitat for red list species. To optimize biodiversity values, urban water management should aim at lowering nutrient levels, stimulating vegetation (diversity of habitat structure) and increasing transparency, which are key factors for macroinvertebrate diversity. We show the potential conservation benefits of water systems in urban areas, but further studies are needed to investigate the optimal design of cities to include biodiversity as an integrated part of the urban environment, thereby sustaining a higher biodiversity in an increasingly urbanizing world.

Simulation of the operation of detention tanks

The performance of detention tanks with different characteristics (volume, on-line and off-line arrangement) has been evaluated according to the results of a continuous simulation. The conceptual simplified model for sewer system simulation (COSMOSS) model has been used to simulate the operation of the tanks. The differences between the performance of on-line and off-line tanks and the influence of the characteristics of different catchments have been examined. According to the results of the simulations detention tanks demonstrated good performances in total suspended solids retention and this evenience can certainly help to prevent water pollution of receiving water bodies in urban areas, even if the differences between the catchments, especially regard to the first flush effect, influence the performance of the tanks. Anyway considerable good efficiencies can be obtained with tank volumes of about 30–50 m 3/ha imp, in terms of number, maximum concentrations and duration of overflows, generally not guaranteed only with overflow devices.

都市気候に及ぼす河川水の熱的影響に関する実測研究 : 隅田川における熱収支と周辺影響の検討

Water bodies in urban area have been expected to mitigate the urban heat island as well as green space. In this paper, we showed the results of observations about heat budget at river water and moving observations to clarify horizontal extent of its thermal effects. Diurnal variations of sensible heat flux estimated by several methods corresponded closely with each other, though these values didn't exceed 100W/m2 even in the peak about midday. Estimated heat storage term occupied more than 90% of net radiation during daytime. According to the numerical simulation, observed water temperature variation required equivalent heat conductivity for actual stirred water about forty times as much as that of stagnant water. This heat balance is completely different from that of green space characterized large latent heat flux. On the other hand, horizontal sensible heat flux from adjacent built-up area to the river space also estimated by eddy correlation method at riverside terrace. Turbulent heat flux across the river-edge amounted to 250W/m2 in daytime, which greatly surpassed vertical sensible heat flux at water surface. The horizontal limits of river-effect along the street crossing the river were about 300m from river-edge, and there was no clear relation between this limits and wind speed.