Urban Stormwater Management Systems Research Articles

Enhanced resilience in urban stormwater management through model predictive control and optimal layout schemes under extreme rainfall events

Optimizing the layout of urban stormwater management systems is an effective method for mitigating the risk of urban flooding under extreme storms. However, traditional approaches that consider only economic costs or annual runoff control rates cannot dynamically respond to the uncertainties of extreme weather, making it difficult to completely avoid large accumulations of water and flooding in a short period. This study proposes an integrated method combining system layout optimization and Model Predictive Control(MPC)to enhance the system's resilience and effectiveness in flood control. An optimization framework was initially built to identify optimal system layouts, balancing annual average life cycle cost (AALCC) and resilience index. The MPC was then applied to the optimal layout selected using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method, aiming to alleviate inundation cost-effectively. The adaptability of MPC to varying sets of control horizons and its efficacy in managing the hydrograph and flood dynamics of urban drainage system were examined. Conducted in Yubei, Chongqing, this study revealed patterns in optimal layout fronts among various extreme design rainfalls, showing that peak position rate and return period significantly influence system resilience. The contribution of MPC to the optimal system layout was particularly notable, resulting in improved instantaneous and overall flood mitigation. The application of MPC increased the resilience index by an average of 0.0485 and offered cost savings of 0.0514 million yuan in AALCC. Besides, our findings highlighted the importance of selecting an optimal set of control horizons for MPC, which could reduce maximum flood depth from 0.43m to 0.19m and decrease conduit peak flow by up to 14% at a flood-prone downstream location.

Estimating Combined Effects of Climate Change and Land Cover Change on Water Regulation Services of Urban Wetlands in Valdivia, Chile

AbstractThe relationship between cities and wetland cover varies across the globe, with some cities converting wetlands to low‐ and high‐density urban cover and others preserving, conserving, or restoring wetlands, or constructing new ones. However, the scientific literature lacks studies relating changes in systemic flood risk in an urban stormwater management systems to changes in wetland cover. Furthermore, whether and how such relationships are affected by changing storm intensity under climate change is unknown. We present a case study on the effects of changes in urban wetland extent and storm intensity on flooding in an urban drainage system in Valdivia, Chile, under several co‐produced future scenarios and historical trends of development. We used data derived from stakeholder workshops and historical landcover to determine four plausible scenarios of urban development, plus one business‐as‐usual scenario, in Valdivia through the year 2080. Additionally, we used historical precipitation data and downscaled climate data to estimate event rainfall from extreme storms in the year 2080. We found that system flood volume and time the system was flooded increased with increasing wetland loss and rainfall volume. Mean rate and hour of peak discharge were unaffected by wetland loss. Infiltration's relative role in reducing flooding diminished as wetland loss increased. Cities may still experience dangerous and/or unacceptable flooding even with extensive wetland coverage and will likely need to pair conservation with additional improvements in their stormwater management systems and contributing watersheds.

A deep dive into green infrastructure failures using fault tree analysis

Green Infrastructure has transformed traditional urban stormwater management systems by fostering a wide range of service functions. Despite their popularity, green infrastructure's performance can deteriorate over their lifecycle, leading to operational failures. The operation of green infrastructure has predominantly relied on reactive maintenance strategies. To anticipate malfunctions and enhance the performance of green infrastructure in the long run, failure data needs to be recorded so that deterioration processes and component vulnerabilities can be recognized, modelled and included in predictive maintenance schemes. This study investigates possible failures in representative GIs and provides insights into the most important events that should be prioritized in the data collection process. A method for qualitative Fault Tree Analysis using minimal cut sets are introduced, aiming to identify potential failures with the minimum number of events. To identify events of interest fault trees were constructed for bioswales, rain gardens and green roofs, for three groups of service function failures, namely runoff quantity control, runoff quality control and additional service functions. The resulting fault trees consisted of 45 intermediate and 54 basic events. The minimal cut set analysis identified recurring basic events that could affect operation among all three green infrastructure instances. These events are ‘trash accumulation’, ‘clogging due to sediment accumulation’, and ‘overly dense vegetation’. Among all the possible cut sets, events such as ‘plants not thriving’, ‘invasive plants taking over’, and ‘deterioration caused by external influences’ could potentially disrupt most of the service functions green infrastructure provides. Furthermore, the analysis of interactions between component failures shows vegetation and filter media layer failures have the highest influence over other components. The constructed fault trees and identified basic events could be potentially employed for additional research on data collection processes and calculating the failure rates of green infrastructure and as a result, contribute to a shift toward their proactive operation and maintenance.

Modeling benefits and tradeoffs of green infrastructure: Evaluating and extending parsimonious models for neighborhood stormwater planning

Green infrastructure is often proposed to complement conventional urban stormwater management systems that are stressed by extreme storms and expanding impervious surfaces. Established hydrological and hydraulic models inform stormwater engineering but are time- and data-intensive or aspatial, rendering them inadequate for rapid exploration of solutions. Simple spreadsheet models support quick site plan assessments but cannot adequately represent spatial interactions beyond a site. The present study builds on the Landscape Green Infrastructure Design (L-GrID) Model, a process-based spatial model that enables rapid development and exploration of green infrastructure scenarios to mitigate neighborhood flooding. We first explored how well L-GrID could replicate flooding reports in a neighborhood in Chicago, Illinois, USA, to evaluate its potential for green infrastructure planning. Although not meant for prediction, L-GrID was able to replicate the flooding reported and helped identify strategies for flood control. Once evaluated for this neighborhood, we extended the model to include water quality through the representation of dispersion and settling mechanisms for two pollutant surrogates—total nitrogen and total suspended solids. With the extended model, Landscape Green Infrastructure Design Model-Water Quality (L-GrID-WQ), we examined benefits, costs, and tradeoffs for different green infrastructure strategies. Bioswales were slightly more effective than other green infrastructure types in reducing flooding extent and downstream runoff and pollution, through increased infiltration and settling capacity. Permeable pavers followed in effectiveness and are suggested where spatial constraints may limit the installation of bioswales. Although green infrastructure supports both flooding and pollution control, small tradeoffs between these functions emerged across spatial layouts: strategies based on only curb-cuts better controlled pollution, while layouts that followed the path of water flow better controlled flooding. By illuminating such tradeoffs, L-GrID-WQ can support green infrastructure planning that prioritizes unique concerns in different areas of a landscape.

Using stomatal conductance capacity during water stress as a tool for tree species selection for urban stormwater control systems

Improving our understanding of how different tree species function in urban stormwater management systems is important, as tree pits may provide a temporary reservoir for stormwater and as trees have the potential to actively reduce stormwater runoff by transpiration. While urban tree planting pits are increasingly used for short-term water storage during stormwater runoff events, this storage can have negative effects on both tree vitality and water removal capacity, since stress from waterlogging result in stomatal closure. However, sensitivity to water stress varies by species. It is therefore important to determine which tree species can maintain long-term vitality and continued transpiration even under water stress, and thus are suitable for such locations. Here, we studied how nine different tree species, varying in expected tolerance to water stress, were affected by short-term and seasonal waterlogging, in a greenhouse experiment. The seedlings (Magnolia x loebneri, Tilia tomentosa, and Sorbus torminalis – low water logging tolerance; Cercidiphyllum japonicum, Rhamnus cathartica, and Fraxinus ornus – medium water logging tolerance; Quercus palustris, Acer saccharinum, and Fraxinus pennsylvanica – high water logging tolerance) were exposed to two days, five days and seasonal waterlogging. The treatments reflected best practice (optimal), suboptimal and total lack of tree pit drainage, using Swedish standards. Stomatal conductance and leaf water potential were determined regularly over a period of 71 days, and morphological adjustments were registered. Four of the species were affected already after two days of waterlogging, with reduced stomatal conductance either during the waterlogging or immediately after, and only the most waterlogging tolerant species were unaffected by the five-day treatment. However, all plants survived waterlogging for almost 30 days before the estimated permanent wilting was reached in some plants. We suggest that tree species selection for stormwater management systems should consider the species’ capacity to maintain high stomatal conductance during waterlogging, as there were clear differences between species. The effectiveness of the selected species could have an important impact on the stormwater management capacity of cities, as well as on other aspects of ecosystem service delivery from urban trees.

Derivation of short-term design rainfall intensity from daily rainfall data for urban drainage design using empirical equations in robe town, Ethiopia

Flooding is a significant impact that regularly affects the majority of cities/towns in developing countries due to inadequate drainage systems that were designed without considering hydrological-hydraulic efficiency caused by design rainfall intensity. Design rainfall intensity is essential to urban stormwater management systems; however, obtaining long-term, short-term design rainfall in developing countries such as Ethiopia is challenging. As a result, this study is conducted to derive short-term design rainfall intensity from daily rainfall data for Robe town using three empirical equations for urban drainage design: Indian Meteorological Method (IMD), Modified Indian Meteorological Method (MIMD), and Ethiopian Road Authority Method (ERAM). The results show that the estimated design rainfall by IMD is greater than other methods; the relationship between IMD, MIMD, ERAM, and existing ranges from 0.57 to 1.001, 1.015 to 1.218, and 0.890 to 1.027, respectively. According to the findings of this study, the design rainfall intensity of all empirical equations is not the same in all return periods and durations. Furthermore, the peak stormwater that caused flooding will vary due to variations in rainfall intensity. Thus, this study strongly suggested that the experts consider each empirical equation and select the accurate design rainfall to design adequate stormwater drainage systems for Robe Town. To manage unexpected urban inundation caused by urban development, short-duration design rainfall and other sub-catchment characteristics will need to be considered.

Impacts of climate change on IDF curves for urban stormwater management systems design: the case of Dodola Town, Ethiopia.

Climate change impacts are one of the global challenges that change the intensity and frequency of rainfall. The Dodola town has previously experienced rainfall-induced flooding effects, and future floods may be more frequent and severe due to possible variations in rainfall intensity due to climate change. In this study, the rainfall intensity-duration-frequency (IDF) curves are updated for the design of urban stormwater drainage infrastructures under climate change to reduce flooding risks. To assess the variations in the rainfall intensity, the future IDF curves for the periods (2020-2100) and two GCMs (CanESM2 and HadGEM2-ES) were derived and compared to the current IDF curves. It was found that rainfall intensities for future climate conditions will differ from the current period for all durations and return periods. The comparison results show that the relative change between future rainfall intensities and historic rainfall ranges from 1.5 to 30.6%, 2.48 to 42.6%, and 3.7 to 23.24% for 2020-2040, 2041-2070, and 2071-2100, respectively. The IDF relationships revealed that as a result of climate change, urban flooding will increase in the future. This study will help to better understand the impacts of climate change on rainfall IDF relationships, as well as have implications for the design of current and future stormwater management systems in Dodola, Ethiopia.

Aedes Aegypti-Insights on the Impact of Water Services.

Epidemics in general and dengue in particular surcharge the health services and the economy. However, the fighting actions are circumscribed to the health sector despite the known positive economic impacts that the investments in water supply and sanitation services (WSS) may cause on society and public health. Besides the fact that urban WSS infrastructure is closely linked to disease prevention, in Brazil, the user's perception and demand are very few and many institutional aspects, like the integration between local WSS, health, environment, and development of city councils, need to be improved and better aligned. In this way, disease control and vector density reduction remain challenges to be overcome. This article addresses the need for greater institutionalization of urban WSS relating them to health aspects from official data. It concludes that the negative impacts of lacking universal access to WSS on dengue and other mosquito diseases are dispersed in all cities, regions, and populations regardless of their degree of development. Furthermore, contrary to what is normally emphasized, the analysis carried out shows that the lack of urban stormwater management systems may be an important component of WSS in preventing the proliferation of dengue disease.

Urban stormwater management for sustainable and resilient measures and practices: a review.

Stormwater drainage in urban areas has become a challenge due to the rapid and random growth of urban areas, removal of vegetation, reduction in the effectiveness of drainage infrastructure, and climate change. Sustainable Urban Drainage Systems (SUDS), Low Impact Development (LID), Best Management Practices (BMP), Water Sensitive Urban Design (WSUD) and the Sponge City Programme (SCP) are various aspects for urban stormwater management in a few parts of the world. Urban hydrology plays a vital role in the urban stormwater management system. However, optimal results can only be possible when the combined effect of climate change, land use patterns, reuse, treatment, ecology, and societal aspects are considered. There is a need to provide sustainable and resilient urban drainage systems to manage stormwater more efficiently. The present review has thoroughly discussed various features related to urban stormwater management, highlighted key drivers, identified knowledge gaps in each of the measures and/or practices, recommended future research needs of urban stormwater management to become sustainable and resilient. Integrated modelling approaches considering various key drivers including reuse and real time governance enables stormwater management to be sustainable and resilient in urban environments.

The Impacts of Climate Change and Porous Pavements on Combined Sewer Overflows: A Case Study of the City of Buffalo, New York, USA

Combined sewer overflows (CSOs) release pollutants collected in urban runoff into local waterways, impacting both aquatic life and human health. The impact of climate change on precipitation may result in an increase in the frequency and magnitude of heavy precipitation events, with a corresponding increase in CSO discharges. The installation of Green Infrastructure (GI) such as Porous Pavements (PP) is a resilient approach to mitigate CSO events. However, an understanding of the impact of climate change on CSO events and the effectiveness of GI practices is crucial for designing sustainable urban stormwater management systems. Using the Storm Water Management Model (SWMM), the performance of PP as a CSO abatement strategy was studied for the city of Buffalo, New York, USA. This paper used the Intensity-Duration-Frequency (IDF) curves for current (1970–1999) and future (2070–2099) design rainfall scenarios, with four rainfall durations (1, 6, 12, and 24 hours) and four return periods (2, 10, 50, and 100 years). The simulation results show that (1) current 100-year events generate CSO volumes similar to predicted 50-year events; (2) CSO volumes could increase by 11–73% in 2070–2099 compared to 1970–1999 when no GI intervention is performed; and (3) the installation of PP can reduce 2–31% of future CSO volume. This case study demonstrates the regional CSO challenges posed by climate change and supports the use of GI as a mitigation strategy.

A Study on Implementation of Low Impact Development as an Urban Stormwater Management Technique in Srinagar City: Current Trends, Issues and Challenges

Abstract: The Severity as well as the frequency of short-duration, but damaging, urban area floods have increased in recent years across the world. Alteration to the urban micro-climate due to global climate change impacts may also exacerbate the situation in the near future. The events of floods have increased in Srinagar city as well over the past decades. Sustainable urban stormwater management using low impact development (LID) techniques, along with conventional urban stormwater management systems, can be implemented to mitigate climate-change-induced flood impacts in Srinagar. In this study, the supposed effectiveness of LIDs in the mitigation of urban flood in Srinagar city is analysed keeping in view their limitations at the same time. A critical research on the success of these techniques in urban flood mitigation planning in Srinagar city is also recommended. On summarising different LID approaches in the world, the results revealed that LIDs can be an efficient method for mitigating urban flood impacts. Most of the LID devices developed so far, however, are found to be effective only for small flood peaks. The major challenges include identification of the best LID practices for the region of interest, efficiency improvements in technical areas, and site-specific optimization of LID parameters. Research and improvements in these areas will allow better mitigation of climate-change-induced urban floods in a cost-effective manner and will also assist in the achievement of sustainable development goals for Srinagar city and will help us to tackle the increasing problems of water logging and floods in the summer capital of Jammu and Kashmir. Keywords: Climate change, Urban floods, stormwater management, Low Impact Development, Srinagar city, Drainage in Srinagar, Pluvial flooding.

An integrated optimization and rule-based approach for predictive real time control of urban stormwater management systems

A smart decision making framework for stormwater management systems is designed through predictive real-time control (RTC) of the outlet gate of a stormwater basin. The proposed framework offers a cost-effective non-structural solution for dynamically controlling stormwater basins through manipulating the outlet gate and providing optimized outflow set-points. An integrated RTC optimization and rule-based approach is designed to mitigate the impact of the discharged runoff on the receiving watercourse, both in terms of quantity and quality. In this approach, the optimization part provides the optimized outflow set-points for the basin to minimize peak flows during the wet periods, while the rule-based part controls the quality of the discharged water, through sedimentation, by increasing the detention time. Various rainfall data series are used as inputs for a case study stormwater basin to verify the performance of the proposed methodology. The efficiency of the stormwater basin in reducing peak flows and improving the quality of outflow was estimated by comparing, respectively, the peak flows and detention times of the integrated RTC strategy with those of a static approach. The results showed an improved quantity and quality control performance for the studied stormwater basin, in comparison to the static control approach, both in current climate conditions with a peak flow reduction from 73 to 95% and detention times varying from 16 to 30 h, and in future climate conditions with an averagely reduction of 76% in peak flows and an average detention time of 19 h.

An SDG-based framework for assessing urban stormwater management systems

Abstract Nature-Based Solutions for stormwater management on top of handling water should, ideally, deliver a multitude of other services to society; they are often seen as a lever for transforming cities in a more livable, green, resilient and sustainable direction, and these measures should be acknowledged as part of the services delivered. In this study we assess the services that Nature-Based Solutions for stormwater management deliver with reference to targets and indicators from the United Nations Sustainable Development Goals; we also develop local, project level indicators that inform and are informed by the more broad Sustainable Development Goals indicators. We demonstrate through Danish cases ranging from lot to city scale that the proposed framework can help inform decision-makers about the sustainability of Nature-Based Solutions for stormwater management. Despite difficulties in matching local indicators to SDG indicators, this first attempt at an assessment framework provides insight on which services of a project help to work towards the Sustainable Development Goals and, if used in the planning phase, could facilitate the design of projects that work focused and informed towards achieving the Sustainable Development Goals.

Understanding socio-economic benefits of stormwater management system through urban lakes in Western Sydney, Australia

Increasingly, stormwater management systems such as urban lakes and wetlands are being implemented in developing urban areas. They are designed to serve multiple purposes. Urban stormwater management systems have environmental, economic, and social impacts. The main aim of this study was to explore the community values and social and economic benefits of urban lakes in the Western Sydney region of New South Wales, Australia. The study involved two case study sites and community surveys using the tailored design method. For this study, a combination of three methods of data collection was used; online, onsite and letterbox drop off surveys. The survey explored several aspects such as community wellbeing, environment and property value benefits. Responses from the community show that there is an overall positive perception of the lake and associated parkland. When asked, over 70% of the respondents stated that there is a positive impact of the lake on the property prices. Additionally, 50% of residents found that there was moderate to significant impact of the lake on both mental and physical wellbeing of people. Approximately 20% of respondents stated that they would not exercise if the local lake system did not exist. Also, 60% of the respondents stated that the lake improved their quality of life. Furthermore, a hedonic property price analysis was done to quantify the impact of the lake on the surrounding properties. A positive correlation was found between the lake and property prices of surrounding homes. The findings from this study provide evidence to policymakers and municipal councils to encourage investments to improve performance of existing lakes as well as develop new ones in the urban areas.

Advance of the Method estimating the Benefit of Storm Water Usage in Urban Area

The storm water causes the flood in urban area, and it could be treated as a special water resource in storm water management which could be divided into three development phases. The urban storm water management systems are analysed in this paper. The methods estimating the benefit of storm water management including benefit identification, index system and estimate method are introduced.

The Co-Evolution of Institutional Logics and Boundary Spanning in Sustainability Transitions: the Case of Urban Stormwater Management in Melbourne, Australia

Institutions and actors both play a critical role in sustainability transitions, yet they have never been investigated together. This study combines both dimensions, systematically applying an institutional logics and boundary spanning lens to examine the interplay between structure and agency over the course of a particular system innovation: the case of urban stormwater management in Melbourne, Australia. Looking through this dual lens reveals the socio-institutional patterns and mechanisms that determine inertia and practice change in the urban stormwater management system. We found that structure and agency co-evolve; when their relationship changes, the dynamics between boundary spanning and institutional logics change too – as do the corresponding niche and regime developments. Our findings suggest that even radical innovations can be successfully institutionalized when using certain forms of boundary spanning at specific phases of a system innovation.

Urban stormwater thermal gene expression models for protection of sensitive receiving streams

AbstractThermal impact of typical high‐density residential, industrial, and commercial land uses is a major concern for the health of aquatic life in urban watersheds, especially in smaller, cold, and cool‐water streams. This is the first study of its kind that provides simple easy‐to‐use equations, developed using gene expression programming (GEP) that can guide the assessment and the design of urban stormwater management systems to protect thermally sensitive receiving streams. We developed 3 GEP models using data collected during 3 years (2009–2011) from 4 urban catchments; the first GEP model predicts event mean temperature at the inlet of the pond; the second model predicts the stormwater temperature at the outlet of the pond; and the third model predicts the temperature of the stormwater after flowing through a cooling trench and before discharging to the receiving stream. The new models have high correlation coefficients of 0.90–0.94 and low prediction uncertainty of less than 4% of the median value of the predicted runoff temperatures. Sensitivity analysis shows that climatic factors have the highest influence on the thermal enrichment followed by the catchment characteristics and the key design variables of the stormwater pond and the cooling trench. The general method presented here is easily transferable to other regions of the world (but not necessarily the exact equations developed here); also through sensitivity and parametric analysis, we gained insight on the key factors and their relative importance in modelling thermal enrichment of urban stromwater runoff.

Suitability of reclaimed asphalt pavement and recycled crushed brick as filter media in bioretention applications

Bioretention systems are increasingly being used in urban stormwater management systems, whereas quarry materials are used as filter media; however the use of quarry materials in this application reduces valuable natural resources. Such a novel approach of using recycled waste materials would significantly conserve valuable natural resources. A series of laboratory tests included particle size distribution, organic content, pH, specific gravity, flakiness index and hydraulic conductivity. Among the pollutants, total suspended solid (TSS), total phosphorus (TP) and total nitrogen (TN) were selected. A model for bioretention system was simulated to investigate the effectiveness of reclaimed asphalt material (RAP) and crushed brick (CB) materials in trapping selected pollutants. In terms of physical and chemical properties, RAP and CB were found to meet the stringent requirements of various environmental protection authorities. This research further indicates that recycled waste materials can be reused viably as alternative materials in bioretention systems.

Development of Simulation-Optimization Model (MUSIC-GA) for Urban Stormwater Management

Urban development leads to replacement of impervious surfaces with pervious surfaces, vegetation and production of various environmental pollutants. In addition, this phenomenon has increased the devastating effects of urban stormwater and has exacerbated the water quality of many freshwater resources (surface and underground) throughout the world. To alleviate this condition, new models of urban stormwater systems, including Water Sensitive Urban Design (WSUD) as well as its software package, MUSIC, have been developed. Regarding the water sensitive urban design, some urban stormwater treatment devices have been proposed and implemented to alleviate the effects of land use changes and improve the quality of downstream water. Although this new models provide cost-effective urban stormwater management methods, it is very challenging to determine an optimal mixture of various treatment devices and minimize the cost of urban stormwater control systems in this regard. Traditionally, the optimum and cost-effective urban stormwater treatment systems have been developed using simulation models such as MUSIC on the basis of trial and error. It should be noted that the latter models require considerable time to get close to an optimal solution. In this study, a simulation-optimization model of urban stormwater management system has been developed using a combination of MUSIC simulation model and Genetic Algorithm thereof. The simulation-optimization model (MUSIC-GA) greatly reduces the computation time and facilitates direct access to absolute optimal solution. The results of a case study on the application of the developed model in Australia have also shown that there have been some desirable convergences between the results of the simulation-optimization model and absolute optimal solution over various implementations of the model.

Engineering and Environmental Assessment of Recycled Construction and Demolition Materials Used with Geotextile for Permeable Pavements

This paper describes laboratory testing to investigate the suitability of recycled construction and demolition (C&D) materials as alternative subbase materials for permeable pavements. Permeable pavements are increasingly being used as urban stormwater management systems. Three commonly found recycled C&D waste materials, crushed brick (CB), recycled concrete aggregate (RCA), and reclaimed asphalt pavement (RAP), were investigated to assess their suitability as permeable pavement subbase materials. Geotextile was also used in this research to trap pollutants. The laboratory tests included basic physical characterization such as particle size distribution, specific gravity, water absorption, Los Angeles abrasion, California Bearing Ratio (CBR), and modified Proctor compaction tests. In addition, hydraulic conductivity tests were undertaken in a laboratory test setup with different influent suspension percentages and moisture contents. Temporal variations of effluent suspension percentages were investigated to assess clogging effects. It was found that the geotextile layer did not have any effect in terms of permeability of the C&D materials. The chemical assessment included organic content, pH value, trace element, and leachate concentration for a range of contaminant constituents and compared with maximum allowable limits in soil and natural water as well as with the environmental protection authorities' requirements. In terms of geotechnical and chemical assessment for permeable pavement applications, RCA was found to be a suitable alternative construction material for permeable pavements, while CB was borderline and RAP did not meet some of the specified requirements.