Application of Green Roof in Relieving Urban Waterlogging: A Review

Green roof plays a critical role in regulating roof runoff by reducing runoff, delaying runoff generation, reducing runoff peak flow and improving runoff water quality effectively. On the basis of introducing significance and role of green roof, this paper reviewed domestic and international researches on the green roof's control over roof runoff, and analyzed the factors that influence the control of green roof over the runoff, so as to provide a theoretical support and method for the construction of green roofs in urban districts.

Study on the Whole Process Simulation and Regulation Mechanism of Urban Green Ecological Rainwater Drainage System

In view of the frequent waterlogging caused by rapid urbanization and the public’s dissatisfaction with the drainage system,the article based on the concept of the green ecological drainage system,constructed the urban green ecological drainage comprehensive simulation research system,and quickly evaluated pipe network operation and surface water of an industrial park under typical rainfall conditions.The results showed that the drainage capacity of the designed green ecological rainwater drainage system reached 100%,and there was no ponding phenomenon,which indicated that the green ecological rainwater drainage system could effectively solve the practical problems of urban drainage.The green ecological rainwater comprehensive simulation research system had good adaptability.The research results provided the scientific theoretical basis and reference significance for planning,designing,constructing,operating,and managing urban rainwater system scientifically and systematically.

Brief analysis on rainwater regulation and storage for pressure alleviation of municipal drainage system

Rainwater plays an important role in the improvement of the drainage performance while leaving the drainage network structure and capacity unchanged.Based on the comparison of rainwater storage performance in projected rainwater drainage systems it shows that the rainwater storage facilities based on the current rainfall intensity computing formulation can improve the drainage system.The results show that the decentralized rainwater drainage network in municipal drainage helps to reduce the designed rainfall intensity capacity in the drainage network.Thus the effect can be equal to increasing the rainfall duration in the rainwater drainage network design.Therefore the rainwater storage facilities in decentralized networks optimize the rainwater drainage network in community rainwater drainage design.It also reduces the capacity of the drainage network and improves the safety of the municipal rainwater drainage system in residential areas.

Application of Rainwater Garden in Dealing with Drought and Flood in Cities

On the basis of analyzing the concurrency of water resource shortage and flood disasters in Chinese cities, this paper proposed the application of natural water drainage mechanism, and introduction of rainwater garden into the urban landscape architecture design. The drainage ways of green streets including rainwater garden were elaborated, and it was proposed that roadside green belts can be used to save rainwater, realize the resource utilization of rainwater, to deal with the concurrency of drought and food in Chinese cities.

Application of Classical Garden Design in Landscaping of West Sichuan Plain

Taking"Lotus Garden Residential Area"in Dayi County,Chengdu City,on the west Sichuan Plain for example,the signifi cance of combining ecological technologies and landscape design was elaborated,and the means of controlling urban fl ood and waterlogging were explored from the perspective of the basic unit of urban construction,the residential area,so as to offer a new sustainable thought for the environment design of future residential areas.

Coarse-to-fine waterlogging probability assessment based on remote sensing image and social media data

Urban waterlogging probability assessment is critical to emergency response and policymaking.Remote Sensing(RS)is a rich and reliable data source for waterlogging monitoring and evaluation through water body extraction derived from the pre-and post-disaster RS images.However,RS images are usually limited to the revisit cycle and cloud cover.To solve this issue,social media data have been considered as another data source which are immune to the weather such as clouds and can reflect the real-time public response for disaster,which leads itself a compensation for RS images.In this paper,we propose a coarse-to-fine waterlogging probability assessment framework based on multisource data including real-time social media data,near real-time RS image and historical geographic information,in which a coarse waterlogging probability map is refined by using the real-time information extracted from social media data to acquire a more accurate waterlogging probability.Firstly,to generate a coarse waterlogging probability map,the historical inundated areas are derived from Digital Elevation Model(DEM)and historical waterlogging points,then the geographic features are extracted from DEM and RS image,which will be input to a Random Forest(RF)classifier to estimate the likelihood of hazards.Secondly,the real-time waterlogging-related information is extracted from social media data,where the Convolutional Neural Network(CNN)model is applied to exploit the semantic information of sentences by capturing the local and position-invariant features using convolution kernel.Finally,fine waterlogging probability map scan be generated based on morphological method,in which real-time waterlogging-related social media data are taken as isolated highlight point and used to refine the coarse waterlogging probability map by a gray dilation pattern considering the distance-decay effect.The 2016 Wuhan waterlogging and 2018 Chengdu water-logging are taken as case studies to demonstrate the effectiveness of the proposed framework.It can be concluded from the results that by integrating RS image and social media data,more accurate waterlogging probability maps can be generated,which can be further applied for inundated areas identification and disaster monitoring.