SWMM Model Research Articles

Assessing stormwater control measures using modelling and a multi-criteria approach

This paper presents a methodology for assessing the selection of stormwater control measures (SCM) within an urban drainage system that combines hydrological-hydraulic modelling and multi-criteria analysis (MCA). The methodology's utility is illustrated on urban catchment in the city of Girona, Spain. The SWMM model was applied and calibrated to simulate SCM scenarios. Seven scenarios were evaluated consisting of one grey infrastructure measure using underground storage tank and three nature-based SCM i.e. infiltration basins, infiltration trenches, green roofs, and combinations thereof. These scenarios were evaluated with MCA including combined sewer overflow (CSO) reduction, CAPEX, OPEX, amenity, biodiversity, and feasibility regarding ownership. The results show that the scenario that included only infiltration basins was most favourable, followed by the scenario which combined infiltration basins and trenches. The underground storage tank was the least favourable with the lowest grade, due to high CAPEX and OPEX, and due to single functionality.

Impact of Urban Stormwater Runoff on Cyanobacteria Dynamics in A Tropical Urban Lake

Worldwide, eutrophication and cyanobacteria blooms in lakes and reservoirs are a great concern for water resources management. Coupling a catchment hydrological model and a lake model has been a strategy to assess the impact of land use, agricultural practices and climate change on water quality. However, research has mainly focused on large lakes, while urban reservoirs and their catchments, especially in tropical regions, are still poorly studied despite the wide range of ecosystem services they provide. An integrated modelling approach coupling the hydrological model Storm Water Management Model SWMM and the lake ecological model DYRESM-CAEDYM is proposed for Lake Pampulha (Brazil). Scenarios of increased imperviousness of the catchment and of reduction in the load of nutrients and total suspended solids (TSS) in dry weather inflow were simulated. Runoff water quality simulations presented a fair performance for TSS and ammonium (NH4+) while the dynamics of total phosphorus (TP) and nitrate (NO3−) were poorly captured. Phytoplankton dynamics in the lake were simulated with good accuracy (Normalized Mean Absolute Error, NMAE = 0.24 and r = 0.89 in calibration period; NMAE = 0.55 and r = 0.54 in validation period). The general trends of growth, decline and the magnitude of phytoplankton biomass were well represented most of the time. Scenario simulations suggest that TP reduction will decrease cyanobacteria biomass and delay its peaks as a consequence of orthophosphate (PO43−) concentration reduction in the lake surface layers. However, even decreasing TP load into Lake Pampulha by half would not be sufficient to achieve the water quality objective of a maximum concentration of 60 µg chla L−1. Increased imperviousness in the catchment will raise runoff volume, TSS, TP and NO3− loads into Lake Pampulha and promote greater cyanobacteria biomass, mainly in the beginning of the wet season, because of additional nutrient input from catchment runoff. Recovering Lake Pampulha water quality will require the improvement of the sanitation system. The lake water quality improvement will also require more sustainable and nature-based solutions for urban drainage in order to reduce non-point pollution through infiltration and retention of stormwater and to enhance natural processes, such as chemical sorption, biodegradation and phytoremediation. The integrated modelling approach here proposed can be applied for other urban reservoirs taking advantage of existing knowledge on Lake Pampulha.

A Semi-distributed Model for Predicting Faecal Coliform in Urban Stormwater by Integrating SWMM and MOPUS.

The microbial contamination of urban stormwater has an important impact on human health and stormwater reuse. This study develops an exploratory semi-distributed model, MOPUS_S, which can simulate faecal coliform levels in separate sewer systems in urban catchments. The MOPUS_S was built by coupling the SWMM model and the microbial MOPUS model. The parameters associated with the deposition and wash-off of microorganisms were more influential than those related to microorganism survival processes. Compared to other existing bacterial models, MOPUS_S showed comparable performance in predicting faecal coliform concentrations. The performance varied largely between rainfall events, with Nash-Sutcliffe efficiency (NSE) values ranging from −5.03 to 0.39 and R2 ranging from −0.02 to 0.83, respectively. The model simulation results for low and medium concentrations were better than those for the peak concentrations. Poor simulation results of peak concentrations obviously affect the overall model performance. In general, MOPUS_S could be capable of predicting the faecal coliform load in urban catchments and be a useful tool for urban stormwater management planning.

The transferability of SWMM model parameters between green roofs with similar build-up

While extensive green roofs are popular measures for reducing and delaying stormwater runoff, design tools are needed to better predict roof performance based on material properties, geometry and climate. This paper investigates the EPA’s Storm Water Management Model’s (SWMM) green roof module for this purpose based on observed runoff from several roofs with different build-ups, geometry, and climates. First, the general model performance was investigated and secondly transferability of model parameters for similar roofs but different geometries and climates was tested. Individual models reproduced runoff hydrographs well (NSE 0.56–0.96), while the long-term modelling showed relatively large volume errors most likely due to insufficient representation of evapotranspiration in the model. Model parameters obtained at one site were only partly transferable to similar roof build-up at other sites. Transferability was better from models calibrated with wetter climates and higher intensity events to drier climates, than the opposite way. Multi-site calibration resulted in model parameters performing well for most sites, giving model parameters that could be used for the design of similar roof build-ups in comparable climates. However, large variability in obtained model parameters, large volume errors and the fact that the calibrated model parameters did not directly correspond to measured material properties, place concerns on the generality of the SWMM green roof module as a design tool.

Swmmr - an R package to interface SWMM

ABSTRACTThe stormwater management model SWMM of the US EPA is widely used to analyse, design or optimise urban drainage systems. To perform advanced analysis and visualisations of model data this technical note introduces the R package swmmr. It contains functions to read and write SWMM files, initiate simulations from the R console and to convert SWMM model files to and from GIS data. Additionally, model data can be transformed to produce high quality visualisations. In accordance with SWMM’s open source policy the package can be obtained through github.com or the Comprehensive R Archive Network (CRAN).

Research on Sponge Campus Application Based on Low Impact Development Measures--A Case Study of Wuhan Polytechnic University

In recent years, China has vigorously promoted the construction of sponge cities and achieved good results. The university campus is a relatively independent existence in the city. Due to historical planning and construction reasons, it is easy to accumulate water when the city has a large amount of precipitation. Taking Wuhan Polytechnic University as an example, this paper analyzes the causes of waterlogging on campus from the aspects of urban precipitation, campus planning, rainwater harvesting and utilization, and proposes a series of low-impact development (LID) measures, such as increasing the permeability of paving area, building vegetative ditch, setting up infiltration green belt, and renovating the artificial lake in the school. The author adopted the SWMM model of urban stormwater management developed by the U.S.EPA as a carrier to construct a low-impact rainwater system model, The SWMM model which funded by the US Environmental Protection Agency was used to construct a low-impact development rainwater system model to evaluate the effect of low-impact development measures on ground runoff control.

Accounting for the Spatio-Temporal Variability of Pollutant Processes in Stormwater TSS Modeling Based on Stochastic Approaches

Stormwater quality modeling remains one of the most challenging issues in urban hydrology today. The processes involved in contaminant generation and transport are very complex, with many associated uncertainties, including uncertainty arising from process variability. In this study, the spatio-temporal variability of build-up/wash-off processes in a heterogeneous urban catchment within the Parisian region is assessed based on three stochastic modeling approaches integrated into the physically based distributed hydrological model, the Urban Runoff Branching Structure (URBS) model. Results demonstrate that accounting for process variability at the scale of a hydrological element is important for analyzing the contamination recorded at the catchment outlet. The intra-event dynamics of total suspended solids (TSS) were most accurately selected for the stochastic exponential SWMM model, as this model succeeded not only in simulating the general trend of TSS concentrations fluctuations but also in replicating multiple peaks observed in pollutographs. The advantage of this approach is that it captures the stochastic nature of the processes with minimal prior knowledge and without extensive calibration, though further enhancement is necessary for it to become a useful tool to support decision making.

Optimization of China Sponge City Design: The Case of Lincang Technology Innovation Park

China launched the sponge city (SPC) initiative in 2013 to reduce municipal stormwater runoff. The design criteria are mainly the annual comprehensive runoff coefficient (ACRC) regulated in a design guideline. Numerous SPC alternatives with varied low-impact development (LID) measures can be designed to meet the ACRC. Obviously, the optimization of SPC design is significant. This study provides an approach to SPC design optimization that applies an optimized module of SUSTAIN to simulate SPC performance over a 10-year period. The targeted volume reduction was derived from the SWMM model and corresponded to the ACRC criteria. Based on the reduction, the minimal cost and cost-effectiveness analyses were conducted. The proposed approach was applied to the Lincang Technology Innovation Park (LCTIP) as a test case. Three scenarios were analyzed: The original design implemented on the site, the landscape improved design, and the most economical design. The results indicated that the optimized alternative may save up to 12.3% of the cost while meeting that ACRC value. The approach improves upon SPC design, particularly with regards to flood control. The present research will help decision makers to develop and select the most appropriate SPC design that is most cost-effective.

The nexus of inhabitants and impervious surfaces at city scale — wastewater and stormwater travel time distributions and an approach to calibrate diurnal variations

ABSTRACTWe present an approach to calibrate dry weather flow patterns of people in eight subnetworks of Dresden, Germany. The monitored data was pre-processed, and SWMM model runs were performed. Congruence of modelled results and observed data was evaluated with the Nash-Sutcliffe Efficiency (NSE). New diurnal variation patterns of dry weather flow were quantified based on the presented calibration approach. Most of the modelled hydrographs exceeded an NSE of 0.9 just after the second SWMM model run, which is a sign of model adequacy. Travel time distributions (TTDs) of upstream wastewater from connected people and stormwater from impervious surfaces of the monitored locations were determined, and a dynamic index ƒiA-PE(k) was proposed, determined and its adequacy was assessed. In general, TTDs confirmed a lower population density and a less meshed urban drainage network in the outer parts of Dresden. The functional information within ƒiA-PE(k) considers development characteristics among the subnetworks and within a subnetwork of interest. The presented index is useful to evaluate prospective strategies of developments and the implementation of green and blue infrastructures in residential areas.

Coupling of 1D models (SWAT and SWMM) with 2D model (iRIC) for mapping inundation in Brahmani and Baitarani river delta

River flooding has been causing extensive losses to life and property, which is a serious concern worldwide. To minimize these losses, suitable planning and management practices are required for the floodplain mapping. Flash floods occur almost every year in the deltaic region of Brahmani and Baitarani river basins in India, during the monsoon season. Generally, 1D modelling is considered as a regular practice. But nowadays, model formulations include 1D for the representation of river channels and 2D for representing river floodplains. In the absence of uniform observations, a hybrid model (1D–2D coupled model) has been developed for this deltaic region to identify the extent of inundation and its depth during the flooding, since 1D models alone do not provide detailed information of flooding. Thus, a well-known 2D river hydrodynamic model iRIC was externally coupled with 1D (SWAT and SWMM) models to simulate and visualize flood scenarios and to identify the flood-prone areas. The hydrological model SWAT was calibrated and validated for Brahmani river deltaic basin, with the observed discharge data available. However for Baitarani river basin, observed flow data were missing and only gauge data were available at few monitoring stations. Hence, for Baitarani river basin, the SWMM model was developed and calibrated with the help of Monte Carlo method. Finally, the SWAT- and SWMM-based tributary stream flow outputs were fed together into the iRIC hydrodynamic model as input for flood inundation mapping. The discharge and water gauge data were used for the calibration and validation. The results obtained from the coupled model were found to be in good agreement with the observed data (RMSE value is 0.77 and 0.79 during calibration and validation, respectively), which enabled identification of the flood-prone areas. The developed model may be used as a tool for effective planning and management of natural disasters such as flash floods.

Research on the effect of rainfall flood regulation and control of wetland park based on SWMM model—a case study of wetland park in Yuanjia village, Qishan county, Shaanxi province

Taking the wetland park of Yuan Village in Qishan County of Shaanxi Province as the research object, this paper makes a reasonable generalization of the study area, and establishes two models of low impact development (LID) and traditional development in the park. Meantime, rainwater in the surrounding built up area is introduced to into the park for digestion. SWMM model is used to simulate the variation of the total runoff, peak flow and peak time of two development models in Wetland Park under one-hour rainfall at different recurrence periods.The runoff control effect in each single LID facility in the one-hour rainfall once during five years in the built-up area is simulated. The simulation results show that the SWMM model can not only quantify the runoff reduction effect of different LID facilities, but also provide theoretical basis and data support for the urban rainfall flood problem. LID facilities have effects on runoff reduction and peak delay. However, the combined LID facility has obvious advantages for the peak time delay and peak flow control. A single LID facility is more efficient in a single runoff volume control. The order of runoff reduction by various LID facilities is as follows: Rain garden>combined LID facility> vegetative swale> bio-retention cell > permeable pavement. The order of peak time delay effect by the LID facilities is as follows: combined LID facility> Rain garden> vegetative swale> bio-retention cell > permeable pavement. The order of peak flow reduction efficiency by various LID facilities is: combined LID facility> Rain garden> bio-retention cell > vegetative swale> permeable pavement.

A harmony-based calibration tool for urban drainage systems

The US Environmental Protection Agency's storm water management model SWMM 5·1 is widely used to simulate urban drainage processes both for qualitative and quantitative analysis. In the present work, SWMM 5·1 was applied to the Fossolo urban sub-catchment in Bologna, Italy, and the geographic information system ArcGIS was adopted to reproduce the spatial distribution of rainfall. An innovative and original optimisation procedure was developed, coupling the jazz-music-based harmony search evolutionary algorithm with SWMM 5·1 for the estimation of runoff parameters. Seven historical storm events were taken into account for model calibration and validation. A careful sensitivity analysis highlighted the effectiveness of the calibrated parameters for simulations. The results obtained showed the proposed approach to be a useful tool for the calibration of hydrological parameters in large urban drainage systems, defining a satisfactory correlation between modelled and measured data.

Modelling technique of interaction between pressure and gravity sewage systems

The article presents the issue of cooperation between gravity and pressure elements realized in a common simulation model. The analysis was based on examples characterized by different levels of complexity. It was found that the SWMM model is possible to apply for the analysis of complete gravity-pressure systems, even in the event of a few pumping stations pumping to a common pressure pipeline. The possibility of applying models prepared in such a manner for the assessment of the correctness of pump selection in terms of the time sewage is stored and frequency of the pump starting up.

Flood control in an urban drainage system using a linear controller

Abstract Effective management of floods in densely populated urban areas poses a great challenge. Computer modeling plays an important role in appropriate management of urban drainage systems. In this study an effort has been made to develop an efficient urban drainage model in which hydraulic results obtained from the developed SWMM model have been linked with a Proportional Integral Derivative (PID) controller for controlling floods. The resulting model can optimize flood levels substantially in urban water bodies and hence can be used as an effective tool to mitigate urban flooding.

Modeling Urban Runoff from Rain-on-Snow Events with the U.S. EPA SWMM Model for Current and Future Climate Scenarios

AbstractA methodological study of modeling runoff from rain-on-snow events was conducted using the northern Swedish city of Kiruna as a test case, with respect to physiographic, drainage system, an...

Development of urban runoff model FFC-QUAL for first-flush water-quality analysis in urban drainage basins

An urban runoff model that is able to compute the runoff, the pollutant loadings, and the concentrations of water-quality constituents in urban drainages during the first flush was developed. This model, which is referred to as FFC-QUAL, was modified from the existing ILLUDAS model and added for use during the water-quality analysis process for dry and rainy periods. For the dry period, the specifications of the coefficients for the discharge and water quality were used. During rainfall, we used the Clark and time–area methods for the runoff analyses of pervious and impervious areas to consider the effects of the subbasin shape; moreover, four pollutant accumulation methods and the washoff equation for computing the water quality each time were used. According to the verification results, FFC-QUAL provides generally similar output as the measured data for the peak flow, total runoff volume, total loadings, peak concentration, and time of peak concentration for three rainfall events in the Gunja subbasin. In comparison with the ILLUDAS, SWMM, and MOUSE models, there is little difference between these models and the model developed in this study. The proposed model should be useful in urban watersheds because of its simplicity and its capacity to model common pollutants (e.g., biological oxygen demand, chemical oxygen demand, Escherichia coli, suspended solids, and total nitrogen and phosphorous) in runoff. The proposed model can also be used in design studies to determine how changes in infrastructure will affect the runoff and pollution loads.

Avaliação do papel dos telhados verdes no desenho e desenvolvimento urbano de baixo impacto ambiental e no controle de enchentes na Cidade do Rio de Janeiro

Este trabalho discute o papel dos telhados verdes no desenho e desenvolvimento urbano de baixo impacto ambiental. São aprofundadas as questões relacionadas ao manejo das águas pluviais urbanas e é avaliado o desempenho dos telhados verdes como dispositivos nos sistemas de micro e macrodrenagem. A metodologia envolveu a aplicação de modelos computacionais hidrológicos-hidráulicos através de estudo de caso em bacia hidrográfica localizada em área de paisagem peri-urbana na cidade do Rio de Janeiro. O modelo computacional adotado, SWMM da US-EPA, permite que se insira de maneira hipotética estes dispositivos em edificações pré-existentes. Através do estudo de cenários sem e com inserção de telhados verdes, pode-se avaliar virtualmente o papel destes dispositivos na redução dos volumes escoados superficialmente e da vazão instantânea máxima, assim como das condições de extravasamento da calha fluvial sob chuva intensa real observada no local em abril de 2010. Os resultados permitiram verificar que apesar de não reverter o extravasamento da calha fluvial, os telhados verdes tiveram impacto na redução dos volumes escoados superficialmente, que agravam as enchentes urbanas, e da vazão máxima instantânea em até 10% aproximadamente. A partir destes resultados e da avaliação das outras sinergias dos telhados verdes com o desenho e desenvolvimento urbano de baixo impacto ambiental recomenda-se o incentivo de políticas públicas que possam viabilizar sua adoção nas cidades Brasileiras com vistas à melhoria da qualidade de vida da população que habita os aglomerados urbanos.

Scenario-based projections of future urban inundation within a coupled hydrodynamic model framework: A case study in Dongguan City, China

One major threat to cities at present is the increased inundation hazards owing to changes in climate and accelerated human activity. Future evolution of urban inundation is still an unsolved issue, given large uncertainties in future environmental conditions within urbanized areas. Developing model techniques and urban inundation projections are essential for inundation management. In this paper, we proposed a 2D hydrodynamic inundation model by coupling SWMM and LISFLOOD-FP models, and revealed how future urban inundation would evolve for different storms, sea level rise and subsidence scenarios based on the developed model. The Shiqiao Creek District (SCD) in Dongguan City was used as the case study. The model ability was validated against the June 13th, 2008 inundation event, which occurred in SCD, and proved capable of simulating dynamic urban inundation. Scenario analyses revealed a high degree of consistency in the inundation patterns among different storms, with larger magnitudes corresponding to greater return periods. Inundations across SCD generally vary as a function of storm intensity, but for lowlands or regions without drainage facilities inundations tend to aggravate over time. In riverfronts, inundations would exacerbate with sea level rise or subsidence; however, the inland inundations are seemingly insensitive to both factors. For the combined scenario of 100-yr storm, 0.5m subsidence and 0.7m sea level rise, the riverside inundations would occur much in advance, whilst catastrophic inundations sweep across SCD. Furthermore, the optimal low-impact development found for this case study includes 0.2km2 of permeable pavements, 0.1km2 of rain barrels and 0.7km2 of green roofs.

Calibration and Evaluation of the Hydrologic- Hydraulic Model SWMM to Simulate Runoff (Case Study: Gorgan)

Calibration and Evaluation of the Hydrologic- Hydraulic Model SWMM to Simulate Runoff (Case Study: Gorgan)

Coupling natural and human processes to simulate changes in the water environment in the Dianchi Lake basin, China

This study proposes a comprehensive simulation model that couples natural and human processes that have traditionally been simulated and analyzed independently. This model was established to support a risk assessment associated with natural disasters and social emergencies. In this paper, a driving mechanism was refined to reflect changes in the water environment and to understand the natural process of non-point source pollution formation in the Dianchi Lake basin. The land use and land cover model, incorporating the changes from the human activities and the natural process, was constructed to understand how humans affect the land use and land cover in the Dianchi Lake basin. Moreover, this paper studies the effects of land use and land cover changes on the non-point pollution and the urban non-point pollution with the SWAT and SWMM models. The land use and land cover changes, especially the growth and spread of the urban area, are changing the structure of the ecosystem and are degenerating the functions of the ecosystem. Ultimately, this study comprehensively simulated natural and human processes to analyze the effects of the human activities on water environment.