LID Facilities Research Articles

The Application and Potential of Multi-Objective Optimization Algorithms in Decision-Making for LID Facilities Layout

The Application and Potential of Multi-Objective Optimization Algorithms in Decision-Making for LID Facilities Layout

Rainwater runoff regulation effect in sponge reconstruction area based on rainstorm flood management model

The study adopts the rainwater regulation strategy based on the rainstorm water management model, and designs a set of rainwater runoff regulation system by monitoring the amount of water, collecting rainfall data, and evaluating the quality of rainwater and natural rainwater, aiming at conserving groundwater, restoring hydrological cycle, reducing urban waterlogging, and optimizing rainwater resources. In the implementation method, the effectiveness of this strategy is evaluated by simulating various scenarios such as without LID facilities, with LID facilities, and secondary rainwater pipe network regulation. The results showed that the Nash efficiency coefficient of the overall model was 0.89, and the changes in chemical oxygen demand, total nitrogen, and total phosphorus water quality indicators were very close to the actual monitoring results. The comparative data before and after the renovation showed that the three water quality indicators were much higher before the renovation. The peak flow rate and outflow time significantly decreased, for example, the peak flow rate decreased from 0.41 m³ /s to 0.39 m³ /s. The outflow time was reduced from 9 min to 6 min. It can be seen that the strategies proposed in the study have effectively improved the quality of urban environment and residents' lives, providing important reference basis for urban rainwater management and water resource protection.

Case study of optimizing Low Impact Development Strategy in School: Allocation by the Drainage Distance

Under the concept of urban stormwater management, integrated efficiency of runoff and pollutant control via low impact development facilities came into focus, whereas a few specific descriptions are provided to quantify the strategy of these facilities, including the selection patterns of the locations and sizes and the connection of LID facilities and the drainage system, which is of important for the evolvement of LID strategy. Based on the weighted multi-object goal, the optimizing LID strategy reduces of runoff, pollutant, peak flow, and flooding time under required precipitation conditions, respectively. This paper concluded LID strategy under local requirements and tougher conditions in the aspect of the size and drainage distance of each facility, a new quantified index of locations of specific types of facilities. Then interpret the adjustment pattern based on the feature of rainfalls by correlation analysis. Correlation results show that the drainage distance of green roofs and the storage tank correlated to stormwater management indicators while the retention facilities did not, and the correlation respectively weakened and stronger when storm intensity increased, helping designers to establish better LID planning for schools.

Research on Multi-objective Optimization Design Method of LID Facility Layout Scheme in Cold Land City

Research on Multi-objective Optimization Design Method of LID Facility Layout Scheme in Cold Land City

Stormwater and flood simulation of sponge city and LID mitigation benefit assessment.

In the context of global climate change and the influence of human activities, the concept of "sponge city" is put forward to realize the purification, collection, and reuse of rainwater. The effective evaluation of LID facilities in sponge cities is of great guiding significance for the promotion and construction of sponge cities. IFMS (Integrated Flood Modeling System) Urban was selected to construct the rainstorm simulation. LID parameters were added to simulate the improvement of urban waterlogging after the construction of sponge city. A reasonable disaster loss assessment method was used to calculate the disaster mitigation benefit brought by the construction of sponge city. Through the comparison of the inundation situation before and after LID facilities' construction, it can be concluded that the mitigation effect of LID facilities on the overall inundation area of the city decreases with the increase of rainfall recurrence period, with the maximum reduction rate reaching 13.63% in the 5-year recurrence period and the minimum reduction rate of 11.06% in the 50-year recurrence period. LID facilities have a better disaster reduction effect for rainfall events with a small recurrence period than for rainfall events with a large recurrence period.

A Neural Network Model to Estimate the Clogging of Ash Mixed Sand Filter

Infiltration filters of LID facilities are frequently confronted with clogging of pores by contaminants. To avoid malfunctioning of LID facilities, filters should be maintained according to the degree of clogging. In this study, clogging was characterized by curves representing the correlation between infiltration rate (<i>Q</i>) and infiltration quantity (<i>IR</i>). To estimate the degree of clogging, a regression neural network model was developed to estimate the label (infiltration quantity) corresponding to the selected features (ash mix ratio, infiltration rate, and variation of infiltration rate). According to the results obtained from the evaluation of accuracy and applicability of the final model trained over the whole training dataset, the following conclusions were drawn: 1) the training of the final model was verified to be correct according to mean absolute errors of 0.00445 and 0.00491 for the training and test datasets, respectively; 2) the final model could be applied to estimate multiple, multivariate clogging curves for arbitrary ash mixing ratios and trained range of time series in terms of infiltration rate; 3) given that the final model could not estimate the clogging curve for future time steps for which the model was not trained, a CNN model or LSTM-RNN model are suggested as an alternative.

LID 적용가능 위치 판단을 위한 중첩지도 분석

Due to climate change and rapid urbanization, most urban areas are paved, and there is insufficient space to infiltrate or store rainwater, and flood damage increases due to heavy rainfall. Research on LID techniques is being conducted to reduce the damage caused by water disasters. A systematic procedure for LID installation, quantitative scale, and facility installation in urban watersheds is required. Therefore, in this study, overlapping maps were analyzed to improve the limitations of water cycle analysis using only land cover maps in urban watersheds. Based on the overlapping map analysis, the procedure for determining the LID facility installation was presented. The peak flood volume and runoff volume were analyzed in Gimhae, Gyeongsangnam-do, using the model (XP-SWMM). As a result of the study, it was confirmed that the exact capacity of the facility can be distributed according to the target amount of water circulation by reflecting the characteristics of the basin or building information.

도시유역 물순환 분석체계 개선연구

Recently, disasters such as floods, localized heavy rains, and typhoons have occurred every year due to climate change. In the past, studies focused on flood control, where damage frequently occurred, but recently, as interest in urban water circulation has increased, awareness of water circulation management has increased. The most important thing to manage the water cycle is to set quantitative water management goals and the exact water cycle application point. Therefore, in this study, to improve the limitations of the water cycle analysis using only the land cover map in the existing urban watershed, an overlapping map analysis was conducted, and an integrated analysis of the building area and building information was conducted for the points where the land cover map was not analyzed. To review the effectiveness of LID facilities, the model was used to analyze Hyoja-dong, Seoul. It was analyzed that peak flood volume was reduced by 28% and 30%, the Return period 5 years, 10 years Rain duration 10min runoff volume was reduced by 18% and 14%, and the flooded area was reduced by 92% and 93%.

Analysis of the Influence of Sponge Bus Bay Stop on Stormwater Runoff

The traditional bus bay stops are prone to ponding, with reduced waiting comfort, low traffic efficiency and easily damaged pavement structure. Given the problem, based on the sponge design of the bay stop in northern China, the rainstorm flood management model under the traditional and sponge modes is constructed, and the runoff condition of the bus stop is analyzed. The results show that the combination design of LID facilities, such as permeable pavement and the recessed green belt has a good control effect on rainwater runoff in the stop section. The larger the range of LID measures adopted in the stop section, the more pronounced the runoff control effect. The combined design of sponge facilities can effectively control rainwater runoff. However, with the increase in rainfall intensity, the control effect of sponge measures on rainwater runoff at the bus stop gradually decreases.

Evaluation of the Feasibility of Foam Glass as Filter Media in Rain Garden

Objectives:In order to recycle and resource waste glass, the feasibility of foam glass as filter media was evaluated, and column experiments using foam glass media were conducted to confirm the applicability as filter media in rain garden. Through this experiment, various design factors to be considered can be derived in application of foam glass media in the rain garden.Methods:Sieve analysis and SEM/EDS analysis were conducted to confirm the physicochemical properties of the foam glass. Column experiments filled with only foam glass and mixtures of sand and foam glass were conducted to simulate rain garden to evaluate the removal efficiency of suspended solids and turbidity using the foam glass media, head difference (<i>Δh</i>) and hydraulic conductivity (<i>K</i>) changes, and calculation of filtered suspended solids loading using both discrete and cumulative mass approach. Finally, comparison of filtration performance with various filter media used in LID facilities was performed to evaluate the feasibility of foam glass media in rain garden.Results and Discussion:Since foam glass media has a lower density than water, homogeneous particle size, and smooth surface with pores of various sizes, foam glass media effectively induces internal capture and external adsorption of suspended solids. Foam glass media has been applied to high suspended solids and turbidity removal efficiency. As the suspended solids inflow load increased, clogging occurred in the pores and the removal efficiency gradually decreased, but the foam glass media with lower density than water was continuously disturbed and rearranged due to the head difference energy, and some clogging were alleviated by rearrangement of pores and channels. The load of suspended solids in precipitated, adsorbed, and retained on the foam glass was calculated using the effluent sample (discrete) collected at regular time intervals and the continuously accumulated sample (cumulative) from the output. The filtered suspended solids load calculated using the cumulative mass approach was higher due to the estimation of the amounts of suspended solids remaining in the filtration column is lower because the samples (discrete) collected at regular time intervals from the output do not reflect the amount of suspended solids that change over time. Thus, the amounts of suspended solids removed through the filtration process can be much more accurately estimated using the cumulative samples. Finally, when comparing the removal efficiency with other filter media, foam glass can be used as excellent filter media with higher removal efficiency and greater lifespan.Conclusion:Foam glass media with smooth surface, pores of various sizes, and lower density than water can rearrange and regenerate pores to alleviate some clogging, resulting in high suspended solids and turbidity removal efficiency for a long period of time. Considering that the amount of suspended solids filtered is determined by various factors such as particle size and distribution, porosity, depth, linear velocity, and inflow load of the suspended solids, the feasibility test using foam glass media through long-term field experiments is warranted. The amounts of suspended solids removed through the filtration process can be much more accurately estimated using the cumulative samples.

Study on Waterlogging Reduction Effect of LID Facilities in Collapsible Loess Area Based on Coupled 1D and 2D Hydrodynamic Model

The accurate evaluation method of LID toward the attenuation of urban flood is still a hot issue. This paper focuses on a coupled 1D and 2D hydrodynamic model, investigating the model parameters set in a collapsible loess area, and the changes in the surface runoff, waterlogged area, and drainage network indicators under different rainfall patterns. The results show that the coupled model can effectively simulate the effect of LID facilities under unaltered and retrofitted conditions. It is found that the infiltration parameters in a collapsible loess area are higher than in other eastern cities by calibration and validation. After implementing the LID facilities, the total runoff, peak flood flow, waterlogged area, runoff coefficient, and drainage pressure under different rainfall patterns have all been reduced. With the increases in the rainfall return period, the waterlogging reduction effect of LID facilities would gradually weaken. The rainfall return period has a great impact on the indicators of surface runoff, waterlogged area, and drainage capacity. The coefficient of rainfall peak has a relatively big impact on indicators of pipelines, such as the proportion of overflow nodes, the proportion of fully loaded pipelines, and the average full-load duration. The rainfall duration has a major impact on the total runoff quantity, runoff coefficient, and average full-load duration.

Rapid Determination Methods for Extent Parameters of Typical LID Facilities in Urban Stormwater Management

Rapid Determination Methods for Extent Parameters of Typical LID Facilities in Urban Stormwater Management

The Multi-Objective Optimization of Low-Impact Development Facilities in Shallow Mountainous Areas Using Genetic Algorithms

From the perspective of whole-area sponge city construction, it is important to scientifically determine the layout plan of LID facilities for controlling urban rainfall and flooding problems, given the topographical features and rainfall runoff characteristics of shallow urban mountainous areas. Current research on the optimization of low-impact development facilities is limited to the central urban area level, with insufficient research on shallow urban mountainous areas, and there is great uncertainty in the layout of LID facilities when multiple objectives are considered. Therefore, this paper applied a genetic algorithm (NSGA-II) to optimize the layout scheme of LID facilities. Multiple objectives of the peak runoff abatement rate, cost, and land area were selected as the optimization objectives, and the optimized results were ranked using the EWM-TOPSIS and VCWM-TOPSIS methods. The 2nd Hebei Provincial Garden Flower Expo (Qinhuangdao) Park was used as the research object for the optimization design. The results showed that, under the premise of water safety, the lowest cost priority was given to the LID facility with a 15.49% share, 99.43% peak runoff reduction rate, and a cost of CNY 1.215 × 107; the lowest area priority was given to the LID facility with a 15.25% share, 99.42% peak runoff reduction rate, and a cost of CNY 1.267 × 107. The EWM-TOPSIS method was also used to obtain the best optimized solution with 16.18% LID facilities, 99.64% peak runoff abatement rate, and a cost of CNY 1.26 × 107, and the worst optimized solution with 12.55% LID facilities, 97.91% peak runoff abatement rate, and a cost of CNY 1.061 × 107. The decision results under different decision-maker preferences were obtained by the VCWM-TOPSIS method. This study showed that the combination of a genetic algorithm and TOPSIS can optimize the layout of LID facilities in shallow mountainous areas more scientifically and efficiently compared to the actual construction plan for building a sponge city.

Study on LID Facilities Comprehensive Effect Evaluation: A case in Campus

The campus is facing the problems of waterlogging and runoff pollution. To mitigate these phenomena, this study constructs a SWMM model using a campus as the study area. The reduction effects of runoff volume and pollutant load under four LID facility combination scenarios were simulated. Eleven evaluation indicators were selected from environmental, economic and social aspects, and the weights of each indicator were calculated by applying the CRITIC method. The relative percentage of different rainfall recurrence periods under the same evaluation indicator was obtained. The composite index method is used to calculate the composite index for each scenario. The combination of rain garden, permeable pavement, bioretention and green roof is determined as the optimal scenario. The Fuzzy pattern recognition method is used to select three representative rainfall events and simulate the reduction effect of runoff volume and pollutant load under four scenarios to further verify the optimal scenario. The results show that the reduction rates of runoff volume and pollutant load under scenario 4 are 2.7%, 4.2% and 4.7% higher than those under scenarios 1, 2 and 3. Based on the above study, the optimal LID facility combination selected in this paper will provide a reference for the construction of sponge facilities similar to this study area.

Application and evaluation of LID facilities in sponge airport, China.

Low Impact Development (LID) is an important approach for the construction of sponge airports. There are few researches on the application of LID facilities in airports. This study mainly analyzes the application of LID facilities in airports, and analyzes the reduction rate of LID facilities on the total runoff, peak present time and peaking volume by constructing EPA Storm Water Management Model (SWMM) in the eastern work area of an airport, which is located in a coastal city in northern China. This study selected three kinds of LID facilities: green roof, bio-detention facility and permeable pavement. Then three LID scenarios were formed according to different layout ratios of facilities (30%-90%), and the effects of different scenarios under different design rainstorms are simulated and analyzed. The results show that the control effect of LID scenario is enhanced with the increase of the proportion of LID facilities. The control effect of LID scenario gradually weakened with the increase of rainfall intensity. For high-frequency rainstorm, the maximum reduction rates of total runoff and peaking volume are 30.89% and 25.58% respectively, and the peak present time delay rate is up to 28.57%. For low-frequency rainstorm, the maximum reduction rates of total runoff and peaking volume are 17.96% and 14.95% respectively, and the peak present time delay rate is up to 6.12%. The flood control effect is more obvious when the LID facilities and pipe network are combined under the condition of low-frequency heavy rain. These conclusions present the effects under different combination ratio of LID facilities. It can provide the technical reference for the design and application of LID facilities for sponge airport construction in the future.

Evaluation model of LID facilities based on the influence of water resource value

Abstract Low-impact development (LID) facilities can not only effectively control rainwater runoff and its pollution, but also enhance the value of urban water resources in water systems. Current studies usually pay more attention to the effect of pollution control indicators, and there are few reports on the evaluation of LID facilities from the perspective of enhancing the value of water resources. Taking the Maluan Bay area of Haicang, Xiamen as an example, an evaluation model of water resource value was established based on the SWMM software and the pollution loss model. From the perspective of economic quantification, the value of water resources brought by three types of LID facilities, such as green roofs, permeable pavement and infiltration gallery, under rainfall conditions in different recurrence intervals was simulated and calculated. In the single rainfall event of 1–10a recurrence interval, the water resource value brought by the green roofs is 679.14–787.49 RMB/hm2, the permeable pavement is 79.07–383.37 RMB/hm2 and the infiltration gallery is 825.45–1,021.79 RMB/hm2. The results show that the value of water resources brought by the three types of LID facilities decreases with the increase of rainfall recurrence interval.

A Research on the Applicable Modes of LID-based Slope Residence Planning

LID provides a new way of thinking to solve urban waterlogging and runoff pollution, and has attracted many scholars to try to integrate the LID concept into the planning and design of residences. After comprehensive analysis of LID’s application into residence planning, it is found that the existing results are not suitable for slope residences, resulting in problems such as difficulty for rainwater to gather into the center of the block, grid-type road patterns not conforming to the characteristics of mountain cities, and some LID facilities layout unsuitable for slope residences.Therefore, combining the characteristics of mountainous areas, this article designs the “hexagonal” road network on behalf of the general road structure of slope residences. Furtehr, we find LID facilities suitable for slope residences and propose the rainwater runoff organization scheme in slope residences corresponding to the LID facilities. Finally, we explore the implementation of LID applicable modes in slope residences via the four continuous levels of architecture, site, road and greenbelt. It is hoped that the current research can supply some ideas to slope residence planning oriented to rain and flood management.

Introduction plan of future integrated water circulation management system using LID facility model verification

Introduction plan of future integrated water circulation management system using LID facility model verification

Research on SWMM Runoff Control Index Decomposition Based on Constraint Optimization Method

The “Sponge City Construction Technical Guide” mentions the method for decomposing and implementing the annual total runoff control rate: volume method and model simulation method. Through research, it is found that the two are based on the control detailed planning level in decomposing the scale parameters of LID facilities. The indicators to each block are allocated through repeated tests through experience and trial calculations, resulting in a lack of scientific rationality in the process and results of the indicator decomposition, and because the Guide is still in the trial stage, there are few researches on the decomposition of runoff control indicators represented by SWMM. Therefore, with the help of MATLAB’s constraint optimization module and SWMM hydro-hydraulic model, this study proposes a complete set of decomposition ideas and methods for the decomposition and implementation of the annual runoff total control rate in the special planning of sponge city, and the index decomposition process through relevant cases Elaborate.

Sponge-city-based urban water system planning: a case study of water quality sensitive new area development in China

Abstract In recent years, sponge city has been booming in China aiming to alleviate urban flooding and improve water quality of natural water bodies. LID/green infrastructure has been gradually introduced to urban planning and urban water system planning. Efficient deployment of LID facilities is critical, which requires modeling and evaluation to develop rational planning. A case study of Guian New Area was presented to show the application of SWMM and the planning methods in sponge-city-based urban water system planning for water quality sensitive new areas development. Based on SWMM, two river network water quality models, the Dongmenqiao River and the Chetian River, were established through a systematic analysis of the case study area. Baseline scenarios were simulated and analyzed, and assimilation capacities of the two river basins were calculated by a trial-and-error method. Finally, two LID scenarios were carefully designed, simulated, and analyzed to support the planning. The simulations showed that in order to meet the strict water quality requirements in Guian New Area, large scales of LID facilities are required to cut down the rainfall-runoff pollution. Moreover, measures such as more frequent cleaning to reduce pollutants accumulation on the ground should also be taken to mitigate the maximum buildups of pollutants.