SWMM-Based Assessment of Urban Mountain Stormwater Management Effects under Different LID Scenarios

The types of urban mountains are diverse, and the surrounding environment is complex. The conditions of runoff generation and convergence in different regions of the same mountain vary. Using the Lijia Mountain in China’s Nanjing City as a case study, this study investigates the effects of such mountain-region-based LID (Low Impact Development) systems. Based on the hydrological analysis of this mountain region, SWMM (Storm Water Management Model) software is used to model and compare the runoff control effects of two LID systems schemes, namely segmental detention and retention and terminal detention and retention. The study’s findings demonstrate that the terminal detention and retention scheme can effectively delay the time of peak flooding and partly reduce peak discharge. In contrast, the segmental detention and retention scheme has a limited delay effect on flood peaks but significantly reduces the peak discharge. This research breaks through the limitations of the previous construction of a single LID scheme for mountainous regions in built-up urban areas. It serves as a theoretical model and technical reference for selecting LID scenarios in response to different mountain conditions.

Hydrological Effects of Prefabricated Permeable Pavements on Parking Lots

Permeable pavements can infiltrate and reduce stormwater runoff in parking lots, but issues around long construction periods and proper maintenance still required proper research and further understanding. The application of precast concrete can help to solve this. In this study, precast concrete components were applied to the design of permeable pavements to form prefabricated permeable pavements. The laboratory study is one of the first to examine the hydrological effect of prefabricated pervious pavements in parking lots. Four kinds of permeable pavements were designed and manufactured. These had different materials (natural sand-gravel, medium sand) which comprised the leveling layer or different assembly forms of precast concrete at the base. Three scenarios of rainfall intensity (0.5, 1, and 2 mm/min) and three rainfall intervals (one, three, and seven days) were simulated using rainfall simulators. The initial runoff time, runoff coefficient, and runoff control rate of each permeable pavement were investigated during the process of simulating. Results showed that the initial runoff time was no earlier than 42 min, the maximum runoff coefficient was 0.52, and the minimum runoff control rate was 47.7% within the rainfall intensity of 2 mm/min. The initial runoff time of each permeable pavement was no earlier than 36 min when the rainfall interval was one day, whereas, the maximum runoff coefficient was 0.64, and the average runoff control rate was 41.5%. The leveling layer material had a greater impact on the hydrological effect of permeable pavements, while the assembly form of precast concrete had no significant effect. Compared with natural sand-gravel, when the leveling layer was medium sand, the runoff generation was advanced by 4.5–7.8 min under different rainfall intensities, and 7–10 min under different rainfall intervals. The maximum runoff coefficient increased with about 14.6% when the rainfall interval was one day. Among four kinds of permeable pavements, the type I permeable pavement had the best runoff regulation performance. The results revealed that all prefabricated permeable pavements used in this study had good runoff control performance, and this design idea proved to be an alternative for the future design of permeable pavements.

Simulation of Urban Storm Water Runoff Control Based on Big Data

The acceleration of urbanization has brought about rapid economic development, but at the same time, it has also brought some damage to the ecological environment. The proportion of hardened area of the ground is higher and higher, and the rainwater runoff pollution caused by rainfall is more and more serious. In order to follow the sustainable development strategy, and for the more stable and high-speed economic development, the control of rainwater runoff pollution is urgent. The purpose of this paper is to simulate the urban storm water runoff control and find the most suitable scheme for storm water runoff pollution control. Because the simulation of SWMM is more accurate than other models, it can directly reflect the situation of rainwater runoff pollution, so the model selected for rainwater runoff in this paper is SWMM, and then build the model, through the collection and collation of the basic data of the study area, the generalization of the sub catchment area and drainage network is completed. Through the analysis of the characteristics of the study area, the rainwater garden and permeable pavement are determined as the scheme to control the rainwater runoff in the study area. Finally, the SWMM model is used to simulate the control effect of rainwater garden and pervious pavement on rainwater runoff pollution control. The experimental results show that the storm water garden can effectively control the impact of SS scouring effect on the environment, significantly reduce the discharge of SS, and significantly reduce the peak concentration of SS, and its ability to control SS increases with the thickness of the surface plant layer. The control ability of rain permeable brick pavement to SS increases with the increase of surface porosity, that is, the control effect of SS is the best when the porosity is 20%.

Carrying capacity and environmental capacity of water resources analysis in Maluku Province of Indonesia

Carrying capacity and environmental capacity of water resources is the ability of the water to support human life, other living creatures, and the balance between the two as well as the ability of the environment to absorb substances, energy and other components that enter or are incorporated into it. The purpose of this research is to analyze the level of carrying capacity and environmental capacity of water resources in several regencies in Maluku Province, Indonesia. The results showed that some water resources were already in a low environmenttal capacity due to limited availability, especially deep groundwater in Wamar Island, Aru Archipelago Regency and the environmental capacity of water resources had exceeded the quality standards set in Indonesia, especially fresh water in Southeast Maluku Regency and Ambon City. Meanwhile, the environmental capacity of fresh water that has exceeded the quality standard is due to the presence of e-colly bacteria. This condition shows the importance of water conservation through regulating human behavior that is not environmentally friendly, building rainwater control and runoff control infrastructure as well as law enforcement efforts related to watershed maintenance and the behavior of communities around water resources.

Modelling the effect of rainfall patterns on the runoff control performance of permeable pavements

With the implementation of low impact development (LID) in urban areas, it is necessary to quantify the actual effectiveness of LID facilities. In this study, a coupled hydrology-hydrodynamic numerical model was utilized to investigate the runoff control effectiveness of permeable pavements in the city centre of Shijiazhuang, China. Two groups of designed rainfall events with the same duration but different rainfall amounts and peak rainfall intensity locations were presented, and the effectiveness of permeable pavement was demonstrated by the reduction in the total runoff volume, water depth, and inundated area. The results indicate that the rainfall amount is the main factor affecting the runoff control of permeable pavements, and their effectiveness decreases with increasing rainfall amounts and peak intensity coefficients. Moreover, permeable pavements are more effective in reducing the residential waterlogging area, and the proportion of the inundated area above a depth of 0.2 m is considerably diminished. This study reveals the response of the runoff control of permeable pavements to different rainfall patterns, which is essential for supporting the design and practical operation of permeable pavements.

Analyses Of The Hydrologic Performance Of Bioretention Facilities

Due to urbanization, and replacing natural pervious lands by impermeable surfaces, the patterns of rainfall-runoff are altered and thus, negatively influence natural water systems regarding both water quantity and water quality. Bioretention as an efficient LID practice has received significant interest in the recent years. Bioretention practice due to its advantages can be considered as one of the most promising LID practices that maintains the fundamental hydrologic functions in a natural environment and can be integrated into neighborhood landscaping. The primary objective of the current study is analyzing the effects of inflow and outflow characteristics on right-of-way (roadside) bioretention facilities. Inlet and outlet flow hydrographs under several design storm conditions were examined. After the formulation of a SWMM model (node and link plus LID), numerical experiments including sensitive analysis will be designed to simulate and investigate the runoff control performance of a right-of-way bioretention facility. The effective length of the bioretention was found by FLOW3D software (finite element). The performance of the bioretention cell with the effective lengths (12 &16m) reinvestigated and results compared to original bioretention cell

Analyses Of The Hydrologic Performance Of Bioretention Facilities

Due to urbanization, and replacing natural pervious lands by impermeable surfaces, the patterns of rainfall-runoff are altered and thus, negatively influence natural water systems regarding both water quantity and water quality. Bioretention as an efficient LID practice has received significant interest in the recent years. Bioretention practice due to its advantages can be considered as one of the most promising LID practices that maintains the fundamental hydrologic functions in a natural environment and can be integrated into neighborhood landscaping. The primary objective of the current study is analyzing the effects of inflow and outflow characteristics on right-of-way (roadside) bioretention facilities. Inlet and outlet flow hydrographs under several design storm conditions were examined. After the formulation of a SWMM model (node and link plus LID), numerical experiments including sensitive analysis will be designed to simulate and investigate the runoff control performance of a right-of-way bioretention facility. The effective length of the bioretention was found by FLOW3D software (finite element). The performance of the bioretention cell with the effective lengths (12 &16m) reinvestigated and results compared to original bioretention cell

Priority Areas for Developing Green Infrastructure in Semi-arid Cities: A Case Study of Tehran

Urban green infrastructure (GI) approach supports building resilience, mitigating greenhouse gases emissions and adapting to the impacts of climate change. However, the development and maintenance of GI in semi-arid cities can be hindered by limitations such as available water resources. In this article, we study priority areas for GI development schemes at the neighbourhood scale through a seasonal vulnerability framework with the case study of two urban districts in the semi-arid city of Tehran, Iran. Heat mitigation and stormwater runoff control are considered as the main objectives of GI development. The results show that priority areas have high levels of land surface temperature, impervious surfaces and population density, with a low proportion of vegetation land cover. The necessary GI services vary in different local climate zones (LCZ) during the year. Although heat mitigation is required in both compact and open LCZs, the runoff control service of GI is also needed for neighbourhoods with compact midrise settings. To promote sustainability at the neighbourhood scale, the findings of the study can be used for initiating nature-based solutions and GI development projects.