Stormwater Management Planning Research Articles

Intersecting social welfare with resilience to streamline urban flood management

Urban policymakers have long searched for stormwater management plans that incentivize stakeholders to adopt Green Infrastructure (GI) while effectively reducing the vulnerability of drainage systems. In this regard, our research introduces a novel framework to develop GI strategies that provide both hydrological resiliency and social acceptance. To achieve this, first, using a coupled Stormwater Management Model (SWMM) and Non-dominated Sorting Genetic Algorithm-II (NSGA-II), optimal alternatives for GI planning were generated. In the optimization process, we used a novel Simple Urban Flood Resilience Index (SUFRI) to consider the internal performance of the system in identifying resilient plans. Derived management strategies warrant runoff volume reduction and resilience improvement up to 31.3% and 55.1%, respectively. In the next step, Utilitarian-based Social Welfare (USW) was employed to clarify the socio-economic behavior of management strategies. Results indicate that while financial incentives significantly motivate developers to implement GI, they cannot guarantee high social welfare, and achieving a sustainable solution requires evaluating both SUFRI and USW layers under different subsidy levels. Visualizing the SUFRI layer revealed a critical failure in the resiliency trend of solutions that cannot be detected by evaluating simpler metrics, such as runoff volume reduction. This highlights the importance of the SUFRI method in conducting deeper evaluations and preventing financial waste. Finally, we navigated the intersection of USW and SUFRI measures to reach an ideal management plan with optimal supporting level. Our findings showed that the selected solution with the highest social acceptability can improve the resiliency of the system by 29 %. This study is a novel combination of the hydrological and social aspects of stormwater management, enabling decision-makers to take significant steps towards sustainable urban development.

Integrative Review of Riparian Buffers Benefits in Urbanized Watersheds

Riparian buffers or riparian corridors are areas of vegetation in the floodplains and areas surrounding a stream. By the early 2000s, numerous national reports and studies of riparian buffer benefits established that vegetation near streams is helpful in protecting the stream from increasing urban runoff, minimizing bank erosion, reducing flooding, and improving overall water quality. However, influential studies concluded that buffer benefits dwindle as urbanization increases, eventually becoming ineffective. This study evaluates more recent research that suggests riparian buffers are more effective at countering urbanization impacts than previously understood, and considers the extent to which we can quantify these benefits and identify the factors that maximize their effectiveness (i.e. greater efficiency based on buffer distance from the stream, extent of stream setbacks, and percentage of impervious cover in the area). Much of the research has been conducted in the Kansas City area in the Blue River Watershed, which begins in Kansas and flows into Missouri River east of downtown Kansas City, Missouri. About 800,000 residents live in the watershed, which includes some of the region’s fastest growing areas. It is critical to protect this major resource, and other regional rivers and streams, for residents of the Kansas City Metropolitan area and the ecosystems that depend on them. It is also critical to provide the latest and best information to the community-of-practice currently updating regional stormwater management planning and design guidance.

Design of a Stormwater Management System in Lady Irene Campus

This project aimed to design an efficient drainage system for Ndejje University's Lady Irene Campus, addressing issues of erosion and flooding exacerbated by recent construction projects. The goal was to create a hydraulic conveyance system that balances environmental protection with structural integrity and affordability. The project involved field reconnaissance, data collection, and analysis of the campus's landscape, soil types, and development trends to inform the design. Methodologically, the project used GPS surveying to create topographical maps and obtained rainfall data to size drainage facilities using the rational method. The peak runoff was calculated considering land use characteristics, while Manning’s formula was applied to design drainage channels and culverts. The design aimed to ensure high hydraulic capacity and prevent erosion with specific slope and material choices. An Environmental Impact Assessment was conducted, addressing noise, dust, water quality, waste management, and ecological impacts. Mitigation measures were recommended to minimize adverse effects during the construction and operation phases. Despite challenges such as limited access to surveying equipment and data, the project concluded with a comprehensive stormwater management plan. Recommendations include rehabilitating the university’s weather station and establishing a project database to support future planning and research. The project underscores the importance of integrating sustainable practices in urban development to safeguard environmental and infrastructural integrity.

DYNAMIQUE DES RISQUES D’ÉROSION RAVINANTE DES TERRES MARGINALES DE LA COMMUNE RURALE D’IDIOFA (KWILU/R.D. CONGO)

The erosion of marginal lands in the Idiofa Rural Commune is a major problem for urban authorities and the local population. This Commune has no integrated stormwater management plan, which has a detrimental impact on its site and its overall socio-economic and cultural development. The main objective of this study is to: (i) Identify the various gullies and their morphometric characteristics, (ii) Map the marginal areas in Idiofa, (iii) Identify the causes of the accelerated gully erosion observed in Idiofa, (iv) Assess the resulting socio-environmental consequences, (v) Understand, discuss and assess the risks, and (vi) Propose strategies to respond to these risks. The method used consisted of two stages: (i) a survey carried out among a sample of 200 people to obtain a population view of the degradation of its environment, (ii) field observations on the inventory of gullies and their dimensions, to complement and validate the data from radar interpretation. EpiData 3.0, Microsoft Excel 2016 and SPSS 22 were used to process the data collected. Thematic maps of the studied phenomenon were designed using ArcMap 10.8, QGIS Desktop 3.36 and Google Earth Pro. According to the results obtained, all the 133 identified ravines left a void volume of approximately 2,530,246 m3. This represents a loss of land of more than 2,000,000 tonnes, with considerable collateral damage.

The storm runoff management strategy based on agricultural ditch nutrient loss characteristics in Erhai Lake, China

Initial flush management is an effective measure to control non-point source pollution (NPSP) in storm runoff. However, determining the parameter of the initial flush in different areas may pose challenges in storm runoff management strategies. To address this issue, Erhai Lake in China, Yunnan-Guizhou Plateau, was selected as an example for the study. Erhai Lake is a typical mesotrophic lake with the profound influence of NPSP. The NPSP control strategy in this area will provide a valuable reference for other lakes. In 2021, 289 storm events and 190 ditchwater samples were detected around Erhai Lake. The average flow in the ditches ranged from 0.004 to 0.147 m3/s, the instant total nitrogen (TN) concentration ranged from 0.28 to 91.43 mg/L, and the instant total phosphorus (TP) concentration ranged from 0.26 to 7.35 mg/L in the storm events. It was found that the concentration of pollutants was lower than expected in the initial flush period. Instead, the event mean concentrations of TN and TP were 9.3 and 2.1 times higher than in the wet seasons, showing high nutrient concentration levels throughout the entire rainfall period. To manage storm runoff effectively, a flow-processes-division method was proposed to analyze the inflow condition and pollutant removal rate in different runoff periods. The peak flow interception strategy was recommended as the optimal stormwater management plan, as it showed the highest inflow conditions and 50% pollutant removal rate.Considering the need to reduce the constant flush of stormwater runoff, it is essential to establish a healthy water cycle system to alleviate NPSP and raise the Erhai water level. The storm runoff management method can serve as a practical tool for lake areas that do not exhibit initial flush characteristics.

The development of a road network flood risk detection model using optimised ensemble learning

Floods are natural phenomena that invade different parts of the globe annually, leaving severe adverse effects on the natural landscape, particularly in areas where humans practice large-scale urban development activities. Inadequate corporate strategic stormwater management or maintenance plans make the issue even worse. Therefore, efforts have been consolidated to confront flood hazards by incorporating precautious and proactive strategies toward better forecasting and preventing flood disasters or even mitigating the damage if it occurs. Further, there is inadequacy in incorporating computational intelligence techniques to detect flood susceptibility in road networks. This paper proposes a data-driven flood risk areas detection model incorporating various ensemble and generic machine learning techniques as well as autoML tools. A systematic and iterative approach is followed to examine different solutions to tackle the data balancing problem, including oversampling and undersampling techniques. Also, hyperparameter optimisation is undertaken using both grid search and genetic algorithms, and the models’ performance using each designated strategy is reported and assessed. The empirical results from the experiments indicate that the optimised ensembled Extremely Randomized Trees classifier proves an ability to perform well on the given dataset with an averaged ROC AUC value of 90% and outperforms several state-of-the-art generic, ensembled, and autoML classifiers in all evaluation measures. The proposed framework could be possibly generalised to other road networks in similar topographical and geological regional areas.

Institutionalizing barriers to access? An equity scan of green stormwater infrastructure (GSI) incentive programs in the United States

ABSTRACT Green stormwater infrastructure (GSI) is part of a suite of sustainability initiatives that are vital to tackling climate change. However, siloed governance structures that traditionally implement stormwater infrastructure are not well-suited to address the cross-cutting goals of such initiatives (i.e. incorporating social equity along with technological aspects). Equity planning centers social equity in policy development and can help ameliorate this siloing. Here, we apply equity planning concepts to examine GSI incentive programs developed in the United States to address current funding gaps. We explore GSI incentive programs included in federally-mandated Stormwater Management Plans (SWMPs). Programs found through a scan of readily available SWMPs ranged from $20 rebates to $500,000 grants, providing a range of opportunities. However, closer analysis of application materials suggests potential institutionalization of inequality through restricted access. Barriers to accessing these programs can limit participation by marginalized or under-resourced communities and instead redirect scarce resources to communities who already have strong capacity. Thus, we argue that centering equity in the development of sustainability incentives and conducting meaningful equity analysis should be applied to GSI programs to reform practice and avoid institutionalizing inequity.

A Web-Based Application for Exploring Potential Changes in Design Peak Flow of US Urban Areas Driven by Land Cover Change

Floods have become increasingly prominent in recent decades causing devastating effects on lives and livelihoods worldwide. Efficient tools to assess the drivers of floods, such as increasing urbanization, could help to minimize flood hazards. Urbanization increases the design peak flow (maximum potential surface water flow from a precipitation event with an average probability of occurring once in a specific recurrence interval), which is a key information needed for designing stormwater management infrastructures such as culverts and storm sewers. A web-based application was developed to explore the potential changes (1985 to 2020) in design peak flow of urban areas across the conterminous United States driven by land cover change. The results indicate a potential increase in design peak flow in urban areas up to 126.6% in 2020 compared to 1985. Of the total 3,535 study urban areas, about 80% (2,840) urban areas increased design peak flow, and about 19% (654) decreased design peak flow. A general pattern of increasing design peak flow was observed during 1985 to 2010, and decreasing pattern was observed during 2010 to 2020, primarily driven by respective increasing (decreasing) and decreasing (increasing) developed areas (croplands). The application provides crucial information by visualizing both spatial and temporal data that could be useful for decision-makers in developing and improving urban stormwater management plans and policies for efficient resource allocations and reducing flood risks.

Sustainable Stormwater Management at Urban Expansion Areas of Potential Significant Flood Risk

The Preliminary Flood Risk Assessment (PFRA) for the Greek territory, according to European Directive 2007/60/EC, was completed in 2012 and was revised in 2019. Areas of Potential Significant Flood Risk (APSFR) were defined (and revised) for each River Basin District (RBD). Meanwhile, in 2018, the Flood Risk Management Plans (FRMPs) were approved - by Greek Authorities - for each RBD. In the FRMPs specific measures are proposed for the funding of Stormwater Management (SM) projects that will be designed according to the principles of Sustainable Development (SD), i.e., Best Management Practices (BMPs), Green Infrastructure (GI), Low Impact Development (LID), Urban Natural Water Retention Measures (NWRM) and Sustainable Drainage Systems (SuDS). Within this framework, a preliminary study is drawn up in order to specify some innovative proposals for Sustainable Stormwater Management (SSM) in three areas located into the APSFR of RBD ‘EL11’ (Eastern Macedonia), located in Northern Greece. Two of these areas, Perigiali and Nea Peramos are coastal, while the third one, Doxato, is a continental, plain area. Urban expansion plans are approved for all three cases. The study proposes the implementation of an Innovative Stormwater Management Plan (ISMP) for each area.

Developing a Practical Tool for Integrating Green Infrastructure into Cost-Effective Stormwater Management Plans

AbstractGreen infrastructure (GI) practices are an effective means for improving the sustainability of stormwater management. Optimized combinations of GI practices with other management practices,...

Phase II MS4 challenges: moving toward effective stormwater management for small municipalities

Federal regulations for municipal separate storm sewer systems (MS4s) in the United States have been in place since 1990 as part of the Nation Pollutant Discharge Elimination System (NPDES), aiming to reduce sediment and pollutant loads originating from urban areas. However, small-municipality (Phase II) MS4s frequently grapple with several challenges, resulting in a lack of stakeholder buy-in and actionable stormwater management plans. We identify five common challenges concerning MS4 requirements based on literature review, professional experience, and feedback solicited from stakeholders, municipal managers, and fellow professionals and offer real-world examples of efficient, effective MS4 frameworks and/or solutions. The five challenges are summarized as beliefs that: (1) agricultural land use is the largest pollutant contributor and the root cause of pollution problems; (2) stormwater management only benefits downstream communities; (3) large, expensive projects are required to comply with regulations; (4) maintenance, monitoring, and inspection of best management practices (BMPs) is overwhelmingly complex and expensive; and (5) a lack of direct funding makes complying with regulations an impossible task. These challenges are universal in nature for Phase II MS4 permittees and can create real barriers for effective stormwater management. However, we found many examples of methods or techniques to effectively address these five specific challenges, making them well-suited and important for discussion. BMPs can create tangible improvements for surrounding communities (e.g., reduced streambank erosion and flooding), and improved understanding of the structure and options within the MS4 program will help small municipalities make informed choices about management plans.

A review of the progress in Chinese Sponge City programme: challenges and opportunities for urban stormwater management

AbstractUrbanization has been the main driving force for China's economic growth in recent years; however, the highly concentrated urbanized lifestyle has brought many environmental problems to residents, the most urgent of which is urban stormwater management. Some countries have proposed plans for urban stormwater management, such as Low Impact Development (LID), Water Sensitive Urban Design (WSUD), and Sustainable Urban Drainage Systems (SUDS). As a country with relatively underdeveloped urban stormwater management, China's government proposed an ambitious urban stormwater management plan in 2014, called the Sponge City Programme, which means that a city is designed to act like a sponge, with good ‘resilience’ in adapting to environmental changes and coping with natural disasters. As of 2021, this programme has led to SCP projects in 30 pilot districts all over China, the Sponge City Programme construction impacts both urban development and residents' lives. However, there are risks and challenges associated with these projects. Using government research documents as a framework, this paper carefully reviews the progress of the Sponge City Programme in recent years and shows the main challenges faced by the Sponge City Programme in terms of connotation, investment, and technology. On this basis, the paper puts forward practical suggestions for the development of the Sponge City Programme and details potential opportunities of new technology, ideology, planning, and flexible investment.

Measuring the Direct and Indirect Effect of Scientific Information on Valuing Storm Water Management Programs With a Hybrid Choice Model

AbstractWe use scientific information to develop a realistic hypothetical scenario for storm water management and water quality improvements in a stated preference valuation survey. We then provide different treatment levels of the scientific information to survey respondents. Using a hybrid choice model, we find that scientific information has no direct influence on referendum votes in favor of a storm water management program. However, different levels of scientific information have an indirect effect by influencing respondent concern about storm water runoff and by changing perceived understanding of the storm water management plan. We show that both of these effects, neither of which are apparent in standard logit models, have implications for valuing a storm water management plan. Our results suggest that researchers should be aware of how their choice on the information provided may have a subtle influence on responses in stated preference survey.

Development of a flowchart method for source detection of illicit discharges into stormwater drainage systems in Cape Town

Stormwater drainage systems discharging non-storm water add substantial pollution to urban watercourses, with negative impacts to water quality and aquatic ecosystems. Thus, the elimination of these discharges can be a highly effective non-structural best management practice (BMP) to improve water quality. This study aimed to guide local municipalities whose task it is to control polluted non-storm water entries into the stormwater drainage system. The study evaluated procedures, methodologies and techniques of illegal discharge detection and elimination (IDDE) programme components, as practised internationally, and applied these in a local condition to verify their feasibility and challenges. The paper provides guidance to identify and prioritise investigations for controlling illegal discharges into stormwater drainage systems. Challenges encountered in the study included lack of legal authority to undertake inspection, surveillance and monitoring at private and corporate properties, and to undertake requisite enforcement measures to remove sources of illegal discharges. It is recommended that local governments include in their stormwater management plan a control measure for an IDDE programme. More work is needed to better quantify the pollutant prevention and removal strategies and associated costs.

A Modified Digital Elevation Modeling for Stormwater Management Planning in Segmentalized Micro-catchment Areas

Background and objective: Urban topology can be characterized as impervious, which changes the hydrologic features of an area, increasing surface water flow during local heavy rain events. The pluvial flooding is also influenced by the vertical structures of the urban area. This study suggested a modified digital elevation model (DEM) to identify changes in urban hydrological conditions and segmentalized urban micro catchment areas using a geographical information system (GIS).Methods: This study suggests using a modified DEM creation process based on Rolling Ball Method concepts along with a GIS program. This method proposes adding realized urban vertical data to normal DEM data and simulating hydrological analyses based on RBM concepts. The most important aspect is the combination of the DEM with polygon data, which includes urban vertical data in three datasets: the contour polyline, the locations of buildings and roads, and the elevation point data from the DEM. DEM without vertical data (DCA) were compared with the DEM including vertical data (VCA) to analyze catchment areas in Shin-wol district, Seoul, Korea.Results: The DCA had 136 catchments, and the area of each catchment ranged from 3,406 m2 to 423,449 m2. The VCA had 2,963 catchments, with the area of each ranging from 50 m2 to 16,209 m2. The most important finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified. Flooding data from September 21, 2010 and July 27, 2011 in the Shin-wol district were applied as ground reference data. The finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified.Conclusion: The analysis of the area vulnerable to surface water flooding (SWF) was more accurately determined using the VCA than using the DCA.Key words: Radical urbanization, Surface water flooding, Urban vertical structure

Environmental and economic implications of stormwater management alternatives in rural development

AbstractFloodplain restoration as a means of stormwater management (SWM) can benefit communities and the environment but is uncommonly chosen due to limited familiarity in rural and urban planning. This study uses life cycle assessment and life cycle costing (LCC) to compare four SWM alternatives for a typical rural setting undergoing development. We evaluate a case study in Lancaster County, PA in the Chesapeake Bay Watershed which, through community stakeholder planning, undertook a novel SWM plan by restoring its historic floodplain. We evaluate the life cycle impact assessment (LCIA) metrics, global warming (GW), eutrophication and acidification and cost for each alternative over a 100‐year period of analysis including construction, maintenance, and end‐of‐life decommissioning. Assuming a 5% discount rate, and that soils do not require off‐site hauling due to contamination, the cost and LCIA metrics for floodplain restoration are not significantly higher than the more conventional surface basin alternative. Although LCC is highly sensitive to the transport of soil off‐site, more than doubling the costs for the underground stormwater infiltration basin (USIB) and increasing eightfold the cost for the floodplain restoration, contaminated soil removal is rarely needed on rural land. For USIB, LCIA metrics are sensitive to the choice of recycling versus incinerating plastic components, with recycling resulting in lower GW; and for the permeable pavement alternative, additional maintenance to extend its lifetime shows favorable cost and reduced GW. We conclude that in rural settings where soil is not contaminated, floodplain restoration offers environmental and social benefits for SWM that outweigh its costs.

Applying the index of watershed integrity to the Matanuska–Susitna basin

ABSTRACT The Matanuska–Susitna Borough is the fastest growing region in the State of Alaska and is impacted by a number of human activities. We conducted a multiscale assessment of the stressors facing the borough by developing and mapping the Index of Watershed Integrity (IWI) and Index of Catchment Integrity (the latter considers stressors in areas surrounding individual stream segments exclusive of upstream areas). The assessment coincided with the borough’s stormwater management planning. We adapted the list of anthropogenic stressors used in the original conterminous United States IWI application to reflect the borough’s geography, human activity, and data availability. This analysis also represents an early application of the NHDPlus High Resolution geospatial framework and the first use of the framework in an IWI study. We also explored how remediation of one important stressor, culverts, could impact watershed integrity at the catchment and watershed scales. Overall, we found that the integrity scores for the Matanuska–Susitna basin were high compared to the conterminous United States. Low integrity scores did occur in the rapidly developing Wasilla–Palmer core area. We also found that culvert remediation had a larger proportional impact in catchments with fewer stressors.

Evaluation of Stormwater Treatment Vault with Coanda-Effect Screen for Removal of Solids and Phosphorus in Urban Runoff

AbstractCatch basins commonly are used by cities as part of a stormwater management plan to remove sediment and associated contaminants from stormwater, keeping them in compliance with regulations....

Development of Calculation Procedures to Determine Surface Inundation in Stormwater Management Plans

Development of Calculation Procedures to Determine Surface Inundation in Stormwater Management Plans

A runoff trading system to meet watershed-level stormwater reduction goals with parcel-level green infrastructure installation

Green infrastructure (GI) has been recommended widely to reduce runoff from the built environment. However, reliance on public land for GI implementation could cause a heavy financial burden on local governments. Although economic incentives and market-based mechanisms may encourage public participation in managing stormwater by installing GI on private parcels, a runoff trading market has not been fully developed in practice. To establish a market, in part, requires a watershed-based planning framework and fully informed parcel owners in regard to tradable credits, costs, and benefits. We propose a scenario-based Stormwater Management Planning Support System for Trading Runoff Abatement Credits (SMPSS-TRAC) to facilitate the calculation and allocation of stormwater runoff abatement credits in order to assist the decision-making of GI investment. We apply SMPSS-TRAC to a watershed located in Hamilton County, Ohio, USA and develop five scenarios representing increasing use of GI. We test the scenarios under a 5-year rainfall intensity and set a cap of runoff for each scenario at a level that is equal to the runoff from an undeveloped status (1.03-inch runoff depth for the watershed). With the proposed SMPSS-TRAC, the watershed authority could encourage all parcel owners to install suitable GI or purchase credits from the market. When detention basins are needed to meet a stated goal, the watershed authority would build them on vacant lots and share costs with all parcels within the same sub-catchment. The last scenario with four types of GI installed, shows that the watershed reaches market equilibrium and generates 15,358 m3 credit surplus. SMPSS-TRAC has the potential for including multiple stakeholders' preferences and concerns in searching for preferable scenarios.