Representation of the Drainage Network in Urban and Peri-urban Areas Using a 2D Polygonal Mesh Composed of Pseudo-convex Elements

Recent development dynamics of urban centers forced administrations to deal more frequently with problems linked to the inability of traditional sewer systems to manage rainwater in a sustainable and effective manner. Currently, several laws require compliance with the quantitative and qualitative stormwater limits to be discharged into watercourses but, in parallel with a “regulatory” approach, integrated strategies are increasingly being developed. A fundamental role is carried out by Sustainable Drainage Systems (SuDS), whose basic principle is the management of rainwater at the source, through the implementation of prevention, mitigation and treatment strategies. This study, starting from a project proposal made by different Italian firms and funded by PoliS-Lombardia, aims to assess the benefits deriving from the widespread application of SuDS in the Sesto Ulteriano industrial area, through a comparison between a scenario that represents the current configuration of the drainage network, and an ideal scenario where SuDS are taken into consideration. SWMM5 software was used, in order to simulate the behavior of the drainage network in contexts without and with SuDS, after the construction of the synthetic rainfall data sets. Although only event scale simulations have been conducted so far, the encouraging results suggest that these systems really contribute can to mitigating the effects of flooding in urban areas.

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Compensatory alternatives for flooding control in urban areas with tidal influence in Recife - PE

RBRH ◽

10.1590/2318-0331.011716040 ◽

2017 ◽

Vol 22 (0) ◽

Author(s):

Marcos Antonio Barbosa da Silva Junior ◽

◽

Simone Rosa da Silva ◽

Jaime Joaquim da Silva Pereira Cabral ◽

Keyword(s):

Urban Areas ◽

Drainage System ◽

Infiltration Rate ◽

Urban Drainage ◽

Drainage Network ◽

Storm Water Management Model ◽

Recurrence Period ◽

Detention Tank ◽

Swmm Model ◽

Two Alternatives

ABSTRACT This paper presents a study of compensatory alternatives in urban drainage, using SWMM model (Storm Water Management Model), for the critical point of flooding in an urban area and vulnerable to tide fluctuations, located in Recife. For this, we used the registered information of the micro-drainage network and defined the parameters and variables required for modeling, such as: the subareas of contribution to the drainage system, indicating the percentage of soil waterproofing, equivalent width, slope, and infiltration rate; project rain; and tide curve. Two alternatives were simulated after the model has been calibrated. The first, which is an adaptation of the drainage network, presented maximum reductions in the volume of flooding of 37% for the events with recurrence period of two years and of 58% for five years of recurrence. The second, based on the deployment of a detention tank in the existing network, presented satisfactory results for the event of two years and reduced approximately 38% for events of five years. The results showed that there was a reduction in the area of flooding for the conditions simulated. However, the first alternative would not solve the local flooding problems, it would only attenuate and would increase the overload of the drainage pipes downstream of the modified system, while the second alternative could solve the problem of flooding, with the occurrence of an event of two years.

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The mitigation effect of urban green infrastructure (UGI) on urban waterlogging

10.5194/egusphere-egu21-2514 ◽

2021 ◽

Author(s):

Qifei Zhang ◽

Zhifeng Wu ◽

Paolo Tarolli

Keyword(s):

Green Infrastructure ◽

Urban Areas ◽

Spatial Configuration ◽

Water Cycle ◽

Piecewise Linear ◽

Living Environment ◽

Drainage Network ◽

Biophysical Parameters ◽

Positive Role ◽

The Impact

<p>With the acceleration of urbanization, the impervious surfaces of urban areas have increased dramatically, changing the natural water cycle of the city. It is of great significance for the improvement of urban living environment and the risk management of urban waterlogging to fully understand and play the positive role of UGI in alleviating urban waterlogging. This study attempts to identify the critical factors that alleviate urban waterlogging and examine the effectiveness and stability of UGI in mitigating urban waterlogging in multiple locations. We looked at two highly-urbanized Chinese cities (Guangzhou and Shenzhen) in a comparative study. The waterlogging records from 2009 to 2015 were obtained from the local water authority and the UGI was extracted from the 0.5-m resolution remote sensing images. The complex relationship between urban waterlogging and green infrastructure was quantified and compared through partial redundancy analysis and piecewise linear regression after controlling the conditions of topography, precipitation, and drainage network. The results indicated that the spatial distribution of urban waterlogging events presents a strong agglomeration effect, while the clustering pattern varies in different cities. Furthermore, after controlling the impact of elevation, rainfall, and drainage network, the area percentage and biophysical parameters of green infrastructure are the two most important factors to alleviate urban waterlogging. The influence of these two factors on urban waterlogging is consistent in different cities. This result indicates that more attention should be paid to the area size of green infrastructure and its vegetation biophysical parameters to mitigate urban waterlogging magnitude to the greatest extent. However, the area of green infrastructure must be controlled within a certain range in order to play a corresponding role in alleviating urban waterlogging. We also found that the spatial configuration of UGI also matters. Holding UGI&#8217;s composition constant, the degree of urban waterlogging can be reduced by optimizing the spatial configuration of UGI. This finding provides additional insights that the urban waterlogging can be alleviated by balancing the relative composition of UGI as well as by optimizing their spatial configuration, which is particularly important for a highly urbanized area where land resources for UGI are scarce. This study expands our understanding of the complex mechanism of UGI on urban waterlogging mitigation and provides beneficial enlightenment for the design of UGI.</p>

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Management of minor ailments in primary schoolchildren in rural and urban areas

Child Care Health and Development ◽

10.1046/j.1365-2214.1996.787787.x ◽

1996 ◽

Vol 22 (3) ◽

pp. 167-174

Author(s):

J A Cantrill ◽

B Johannesson ◽

M Nicholson ◽

P R Noyce

Keyword(s):

Urban Areas ◽

Rural And Urban Areas ◽

Rural And Urban ◽

Primary Schoolchildren ◽

Minor Ailments

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Cannabis use in Switzerland: The role of attribution of drug use to friends, urbanization and repression 1The study was supported by the Swiss Federal Office of Public Health (Bundesamt für Gesundheit BAG) Grant 316.96.5980.

Swiss Journal of Psychology ◽

10.1024//1421-0185.60.2.99 ◽

2001 ◽

Vol 60 (2) ◽

pp. 99-107 ◽

Cited By ~ 7

Author(s):

Holger Schmid

Keyword(s):

Drug Use ◽

Urban Areas ◽

Hierarchical Linear Model ◽

Cannabis Use ◽

School Aged Children ◽

Structural Variables ◽

Hbsc Study ◽

Nationally Representative ◽

Highly Correlated ◽

Individual Use

Cannabis use does not show homogeneous patterns in a country. In particular, urbanization appears to influence prevalence rates, with higher rates in urban areas. A hierarchical linear model (HLM) was employed to analyze these structural influences on individuals in Switzerland. Data for this analysis were taken from the Switzerland survey of Health Behavior in School-Aged Children (HBSC) Study, the most recent survey to assess drug use in a nationally representative sample of 3473 15-year-olds. A total of 1487 male and 1620 female students indicated their cannabis use and their attributions of drug use to friends. As second level variables we included address density in the 26 Swiss Cantons as an indicator of urbanization and officially recorded offences of cannabis use in the Cantons as an indicator of repressive policy. Attribution of drug use to friends is highly correlated with cannabis use. The correlation is even more pronounced in urban Cantons. However, no association between recorded offences and cannabis use was found. The results suggest that structural variables influence individuals. Living in an urban area effects the attribution of drug use to friends. On the other hand repressive policy does not affect individual use.

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