Storm Sewer Network Research Articles

Possibility of using the STORAGE rainfall generator model in the flood analyses in urban areas

In this investigation, we evaluated the applicability of the Stochastic Rainfall Generator (STORAGE) as a data source for deriving design hydrographs in urban catchments. This assessment involved a comparison with design rainfall calculated using Intensity-Duration-Frequency (IDF) curves derived from observed time-series data. The resulting design rainfall values from both methods were incorporated into a hydrodynamic model of the storm sewer network. To simulate peak discharge and flood areas, the Storm Water Management Model (SWMM) program was employed in conjunction with SCALGO. Our findings indicate that design rainfall values obtained from the STORAGE model exceeded those derived from the observed time-series, with a more pronounced difference for shorter rainfall durations. Simulations further revealed that peak runoff disparities between the two approaches were most evident at a 0.10 probability of exceedance compared to a 0.01 probability. Hydrodynamic simulations demonstrated that the flooding volume induced by design rainfall based on the STORAGE model surpassed that resulting from observed rainfall. Across all events, both the flooding volume and area from STORAGE were consistently greater than those derived from IDF curves. The integration of the SWMM model with the SCALGO application introduced a novel functionality for dynamic visualization of flooding, offering valuable insights for effective flood management in urban areas.

Inundation risk of sewerage system according to the concepts of hazard and vulnerability-case of Algiers city

Algiers city frequently experiences significant flooding during rainy weather due to the overflow of its storm sewer network (SSN). Through modeling, simulation, and field studies, vulnerable points of the network have been identified. These points are classified based on a combined assessment of hazard and vulnerability. Hazard is estimated using the Analytical Hierarchical Process (AHP) method, which considers the return period, overflowing height, slope, elevation, and waterproofing. On the other hand, vulnerability is determined by population density. Risk is determined by multiplying hazard and vulnerability. Additionally, a classification based on the FMECA method's criticality index has been performed to complement the approach. The concordance between the two methods is evaluated using Lin's concordance correlation coefficient (CCC), showing strong agreement. The sensitivity analysis conducted on the models highlights their reliability and robustness, making the obtained results trustworthy and useful for network managers. This analysis aids in effective flood management by allocating resources and interventions to the most vulnerable areas of Algiers city.

Development of an Analysis Model for Storm Sewer Networks Based on Grid Units

The Storm Water Management Model (SWWM), used for the analysis of storm sewer networks in urban areas, enables precise analysis of watershed runoff, hydraulic analysis and backwater effect in conduits, and so forth. However, it requires the specialized knowledge in parameter extraction, sewer network configuration, and analytical operation, it is somewhat difficult to access at the general engineering companies. Therefore, this study developed a grid-based simplified analysis model that is more convenient in terms of schematic design and feasibility review of storm sewer networks. This model can be used to analyze surface runoff, storm sewer network, and stormwater storage connection configuration at the grid unit, and it uses simplified formulas for basic runoff analysis and storm sewer network flow and storage analysis. In addition, this model can review the rough effects of stormwater storage and various infiltration facilities that can be linked to existing storm sewer network through size calculation of grid units. The developed model was applied to the storm sewer network in the coastal area of Gwangalli, Busan, and our results were compared with the results of the Environmental Protection Agency's (EPA) SWMM. Similar results were obtained in terms of surface runoff and runoff within the storm sewer network, but there were some differences in the amount of storage and overflow. However, results were similar in the occurrence nodes and trends of overflow, and accordingly, it is expected to be useful for the purpose of this model and for simple feasibility studies of various design proposals and rough analysis results.

Assessment of Some Water Quality Parameters in the Storm Sewer Network at Ramadi City, Iraq

This study aims to assess the quality of storm sewer water in Ramadi city before its discharge into the Euphrates River and Al-Warrar Canal. Several samples were taken from the storm sewer in two different periods October and April months. Samples were tested in laboratories which included (PH), electrical conductivity (EC), alkalinity (Alk), total hardness (T.H), calcium (Ca), biological oxygen requirements (BOD5), chemical oxygen requirements (COD), nitrate (NO3). sulfate (SO4) dissolved solids (TDS), suspended solids (TSS), and some heavy metals such as copper (Cu) and zinc (Zn). In this study, the authors suggested a new approach for calibrating WQI values using the multiple linear regression (MLR) model and coefficients analysis The results showed that the (MLR) model is acceptable, the multiple linear regression analysis (MLP) was applicable to calibrate WQI values, and new WQI equation with four variables was developed (SO4, BOD5, TSS and TDS), The results showed that the MLR model has a coefficient of R2 equal to (0.859), which indicates that 85.9% of the variance of the data was explained as well as obtaining significance values greater than 0.05 for each of the absolute WQI value. According to analysis, SO4 is the parameter that has the greatest effect on WQI.

Risk and damage-based optimal design of storm sewer networks using rational and fully dynamic methods, a case study (Tehran region 2).

In this study, the risk analysis is used to determine the return period in which the design cost plus the damage risk cost is minimum. The damage includes the roads and traffic, the lawn areas, and the residential and commercial buildings. The traffic damage is based on two factors, time of delay and social negative impacts. The nonlinear reservoir model is used to convert the rainfall into runoff and the dynamic wave model is utilized to perform the network hydraulic simulation in stormwater management model (SWMM) software. This model is defined as an appropriate model. This model was applied in the risk analysis of a region in Tehran to obtain the optimal return period design. The results indicated that the optimal return period is 10 years. The rational method was also applied to the same region and same return period, but the total design cost of the rational method was greater by 5%. The damage due to the traffic include financial damages due to delays and loss of fuel resources in addition to the dissatisfaction of people due to the psychological burden.

Multilayer modelling as a support tool for flood diagnosis and drainage system design

The use of dual-drainage models has increased in recent decades, mostly because of advances in mathematical methods and geographic information system tools. This type of modelling provides precise diagnoses and can be applied to evaluate stormwater infrastructure and diverse drainage alternatives. Minor and major drainage relations in the Dona Eugênia watershed, Brazil, were analysed in this study. Three alternatives simulated the quasi-two-dimensional hydrodynamic model Modcel. The first alternative considered only the terrain surface layer, representing the current situation. In the second alternative, a layer containing a designed storm sewer was introduced. Considering the previous alternatives as a way to diagnose the main minor and major deficiencies, a third alternative was formulated considering previous projects to solve floods in the watershed, incorporating them in the second alternative with functional minor drainage. The results identified the locations of minor drainage gaps, thus helping to direct efforts to the most critical regions, optimise operations and minimise maintenance costs. The results could also be used to evaluate the effects of storm sewer network discharges in major drainage systems, leading to better design of the drainage infrastructure. The major drainage itself can be optimised, once its responsibility in flooding is identified.

Optimal Design of Storm Sewer Network Based on Risk Analysis by Combining Genetic Algorithm and SWMM Model

The design of an urban storm sewer network is a costly task. Therefore, the design should be done so that the total cost becomes minimal. This requires modeling the problem in an optimization form. Floods are stochastic. Designing such a system is associated with risk. Thus, a project is optimal when both design costs and potential future risks are incorporated. This means that the selection of rainfall-runoff return period has to be based on risk analysis. SWMM software was used to handle hydraulic network simulation and the Network optimization was performed using a genetic algorithm in which the decision variables were the diameter and slope of the pipes. To calculate the cost of runoff damage, relationships for land uses, infrastructure and traffic, were provided. The accuracy of the simulation- optimization model seeking the optimal design of the storm sewer network was approved by a benchmark network evaluation. The developed model was implemented in a region of Tehran city to determine the optimal design return period with a risk analysis approach. The results showed that the 10-year return period with is the optimal return period with an annual damage risk cost of 508.68 billion rials, an annual design cost of 943.78 billion rials and a total cost of 1452.45 billion rials. Therefore, the developed method in which the genetic algorithm and SWMM model are combined in addition to the risk-based design approach is an effective tool for the optimal design of storm sewer networks.

Stormflow against streamflow – Can LID-provided storage capacity ensure performance efficiency and maintenance of pre-development flow regime?

The goal of Low Impact Development (LID) is to restore and maintain the pre-development flow regime. The static storage capacity, which is often used as a parameter in LID designs, provides the maximum capacity of an LID type and is easily quantifiable already at the design phase. However, the static storage approach does not consider the inter-event recovery of storage capacity by infiltration and evapotranspiration. This study investigated dynamic storage capacities of three stormwater management designs with increasing proportions of LID units on a 1.2 ha urban residential block in Southern Finland, to compare their cost-efficiency, as well as their potential in restoring the pre-development flow regime. The cost-efficiency of LID designs was assessed based on their ability to contribute to water losses, and on the additional construction costs required when comparing them to conventional solutions (e.g. asphalt replaced with permeable pavement). The design with a small storage capacity and a large capture ratio, i.e., the ratio of contributing area to LID area, was the least efficient albeit its small construction cost. The design with an appropriate balance between the capture ratio and the LID provided storage capacity was the most efficient option. In assessing the potential of stormwater designs in restoring the pre-development flow regime, the sum of infiltration and flow in storm sewer networks was more representative of the catchment total runoff than flow alone. Finally, an extensive simulation of a large set of differently placed LID units proved useful in a priori identification of the most influential units in the treatment train.

Simulation of Storm Sewer Network Using a Storm Water Man-agement Model (SWMM), Ramadi City as a Case Study

Simulation of Storm Sewer Network Using a Storm Water Man-agement Model (SWMM), Ramadi City as a Case Study

A Study on the Improvement of Reliability Estimation Method for Sewer Network considering Resilience

In city centers, the damage caused by inundation is aggravated by rising populations and urbanization, which extend impermeable areas. Research is needed to identify the inundation risks caused by climate change and quantitatively assess the consequences. In this study, we proposed an improved reliability study which considers resilience in the original evaluation method for the reliability of a storm sewer network. Rainfall-runoff analysises were performed on a part of Bangbae 2 drainage basin in Seoul by applying Storm Water Management Model 5 Ver. Based on the results of the application of excessive rainfall events, the original reliability evaluation method was compared with the improved reliability evaluation method. Consequently, the effect of the improvement of the cluster about 30% was confirmed when selection the central value rather than the existing representative value. The improved reliability evaluation method proposed in this study can be used as a design objective function and as an index for evaluating the inundation risk in adjacent drainage basins.

Modeling Storm Sewer Networks and Urban Flooding in Roanoke, Virginia, with SWMM and GSSHA

AbstractModeling urban flooding is challenging because of complex spatial variations and interactions between precipitation, land cover, and drainage networks. This paper presents a case study of t...

Leachable phosphorus from senesced green ash and Norway maple leaves in urban watersheds

In urban watersheds, street tree leaf litter is a critical biogenic source of phosphorus (P) in stormwater runoff. Stormwater extracts P from leaf litter and transports it, through the storm sewer network, to a receiving waterbody potentially causing downstream eutrophication. The goal of this study is to understand P leaching dynamics of two prevalent tree species (Norway maple (Acer platanoides) and green ash (Fraxinus pennsylvanica)) in three urban residential watersheds in Madison, Wisconsin, USA. Leaf litter was collected from the three basins during Fall 2017 and 2018. Laboratory experiments showed an initial rapid total dissolved phosphorus (TDP) release that gradually plateaued over a 48-hour period. The total TDP released from Norway maple (2.10 mg g−1) was greater than from green ash (1.60 mg g−1). Within the same species, increased fragmentation of leaves led to more rapid initial TDP release, but not greater total TDP release. Increased aging of senescent leaves decreased total TDP release. Incubation temperature and volume of water in contact with leaves may not be critical factors affecting TDP leaching dynamics. Predictive equations were derived to characterize time-variable TDP release of both Norway maple and green ash leaves. Potential TDP release from leaf litter estimated using these equations was compared with field-measured end-of-pipe TDP loads in one of the study watersheds. Our results indicate that preventing leaf litter from accumulating in streets is an important stormwater quality control measure.

Selection of best stormwater management alternative based on storm control measures (SCM) efficiency indices

Abstract Overcoming conventional stormwater management problems and finding appropriate control methods for safely discharging excess runoff from impervious areas is an essential part of any sustainable urban planning. This study aims to analyze the performance of different storm control measures (SCMs) applied to Vellore Institute of Technology (VIT) campus situated in Vellore, Tamil Nadu, which is a highly urbanized catchment. Different SCMs were designed for the VIT campus based on low impact development (LID) options available in stormwater management model (SWMM) software. The most suitable SCM was selected based on its ability to match pre-urbanized hydrographs as close as possible. The SCM location was identified by a localized survey, in such a way that there is least disturbance to the existing storm sewer network. The percentage reduction of peak flow under each proposed SCM were obtained as follows: bio-retention (19.8%), rain garden (18.69%), green roof (49.17%), infiltration trench (20.02%), permeable pavement (22.6%), rain barrel (12.95%), rooftop-disconnection (10.79%) and vegetative swales (17.23%). The results indicated that Option 9 (combination of permeable pavement and bioretention) and Option 10 (permeable pavement and infiltration trench) were better at reducing peak runoff and increasing infiltration. The peak runoff reduction for Options 9 and 10 were observed to be 32.05 and 39.81%, whereas the percentage increase in infiltration was observed to be 25.7 and 29.45% respectively.

Storm sewer pipe renewal planning considering deterioration, climate change, and urbanization: a dynamic Bayesian network and GIS framework

ABSTRACT Risk-based renewal planning is essential for the reliable and continuous functioning of infrastructure systems. In this paper, we propose a risk assessment framework for storm sewer networks considering both hydraulic capacity and asset deterioration. The method is designed for a city-scale analysis and can provide an insightful result even when there is incomplete information. The objective is to assign a relative risk score to each pipe to inform replacement priorities. Moreover, we adopt a dynamic framework to proactively assess risk in different time horizons to investigate the impact of climate change and urbanization. A Dynamic Bayesian Network (DBN) model is used to capture dependencies among indicators, quantify uncertainty, and update belief when new information becomes available. Geographic information system (GIS) applications are used to collect and process model input data as well as visualize analysis results. Finally, the method is demonstrated on a storm sewer network in the city of Vernon, Canada.

Hydraulic calculations of storm sewer networks

Surface run-off (SR) produced on the territory of cities and other settlement as a result of atmospheric precipitation is an intensive source of the technogenic pollution of environment, including the waterbodies. In accordance with the existing legislation of the Russian Federation, SR requires organized disposal and treatment according to the standards of regulatory documents. In this article we analyze the European document BS EN 752:2017 with regard to determining the flow-rates of surface (storm-water) run-off, and the calculations are made by the authors, which demonstrate that the application of foreign software products is impossible in Russia, due to the differences between the existing Russian regulatory and methodological documents and the European standards. Nevertheless, for the development of electronic models of hydraulic calculations for a storm-water drainage network, the mathematical relationship, which most adequately characterizes the type of surface run-off hydrograph most frequent for the territory of the Russian Federation as a result of atmospheric precipitation, was found. The relevant algorithm of the hydraulic calculation of storm-water drainage networks was also developed.

ANALYSIS OF RAINFALL IN THE KAZAKHSTAN

Before building the storm sewer networks the analysis of precipitation is very important. The issues of assessing the reliability of the information on the annual amounts of precipitation in the meteorological monitoring system of the KazHydroMet State Hydrometeorological Service of Kazakhstan are considered. An assessment is made of the homogeneity of the spatial correlation function, as the basis of the cartographic modeling of the statistical parameters of annual precipitation amounts. A special study aimed at studying the processes of cyclical fluctuations in the temporal variability of annual and summer precipitation amounts for stations representing all regions of the country. The data of daily precipitation of Kazakhstan in the period 1936-2017 were processed. When processing data, an open-source computer program R was used. The results will be useful for designers and researchers. A statistically significant increase in the maximum daily precipitation of 2–4 mm per 10 years was recorded at the Arkalyk, Aksay, Atyrau, Ushtobe, Bektauat and Karabalyk meteorological stations. At some stations in the Akmola and Pavlodar regions, as well as in the south and southeast of the republic, a statistically significant reduction of 2-6 days per 10 years was observed for the maximum duration of the period without precipitation.

A Temporal Distribution Method of Probable Rainfall for Planning a Storm Sewer Network in an Urban Area

Recently, rainfall runoff models have been introduced for planning a storm sewer network in an urban areas because they can calculate the flood hydrograph as well as peak flow. This would solve the flood problem for the entire watershed. While a rainfall hyetograph is an essential input to a rainfall-runoff model, there is no proper guideline for an urban area on how to obtain a rainfall hyetograph from a temporal distribution of probable rainfall. The purpose of this study is to suggest an appropriate method for temporal distribution of probable rainfall for a storm sewer network. Thus, Huff’s quartile method, which is widely used in practice, and the alternating block method (ABM), which is known to be reasonable for planning medium- or small-scale drainage facilities, were compared. The two estimation results were used for the comparison: the probable rainfall amounts by duration; the peak flows from arbitrary watersheds. The results showed that the ABM was more appropriate than the Huff method from three perspectives: reproducibility of actual rainfall phenomena, accuracy of peak flow estimates for small drainage areas in urban regions, and consideration of continuity for the storm sewer network. These results may contribute to enhance planning methods for a storm sewer network in urban areas. Keywords: Temporal Distribution, Rainfall, Storm Sewer Network, ABM, Huff

A Study on the Characteristics of Urban Storm Sewer Networks from a Network Perspective

Most of the rainfall over impervious surfaces of urban areas flows along the surface of the ground, flows into the storm sewer network, and is discharged from the catchment. Therefore, the proper design of storm sewer networks and understanding of the characteristics of storm sewer networks should be considered first in reducing urban flooding. In this study, we selected watersheds with a general sewer network in urban areas. It was assumed that the sewer network was a storm sewer network with the characteristics of a complex network, such as a natural stream. The concepts applied in natural stream systems were applied to the target watersheds. The laws of stream numbers and stream lengths were calculated using Horton's law, which is applied to the stream pattern of natural streams. It was deemed necessary to study the application of a different theory in addition to the existing theory that was applied in this study in the future. If the criteria for the characteristics of rainwater pipes are also presented in the design of rainwater pipes in urban areas, then more effective water duct design and urban flood reduction will be possible. Keywords: Storm Swere Networks, Horton’s Law, Law of Stream Numbers, Law of Stream Lengths

Impact of the Storm Sewer Network Complexity on Flood Simulations According to the Stroke Scaling Method

For urban watersheds, the storm sewer network provides indispensable data for flood modeling but often needs to be simplified to balance the conflict between the large amount of data and current computing power. The sensitivity of a flood simulation to the data precision of a storm sewer network needs to be explored to develop reasonable generalization strategies. In this study, the impact of using the stroke scaling method to generalize a storm sewer network on a flood simulation was analyzed in terms of the total inflow of the outfalls and flood results. The results of the three study basins showed that different complexities of a sewer network did not have a significant effect on the outfall’s total inflow for an area with a single drainage system but did for an area with multiple drainage systems. In addition, serious flooding was mainly distributed at the backbone pipes, which can be identified with the simplified sewer network. Several effective generalization strategies were developed for sewer networks that consider the distribution characteristics of the drainage system and application requirements. This study is theoretically important for better understanding the data sensitivity of flood modeling and simulation and practically important for improving the modeling efficiency and the accuracy of urban flood simulation.

Stormwater Management in Urban Areas of South Korea

In early start of monitoring, a pathway for high runoff volumes and peak flows during rainfall period towards downstream of a waterbody was provided from storm sewer network, but later on it was realized to deal with stormwater quantity and quality to develop new approaches and management techniques. In early 90’s NPS pollution issue was highlighted in korea, but only limited studies were conceded out up to the year 2000, however reasonably huge numbers of studies were directed for environmental science. After the recognition of NPS, Ministry of Environment in 1998 has introduced NPS as a major contributor in total maximum daily load management system (TPLMS) and waterbodies impairment, which is one of the guidelines of widespread water improvement strategies for main rivers. It contains a number of agendas that intention is to improve, maintain or restore the water quality in national water systems. It can be potted that stormwater management has evolved during the decades as of understanding with its impacts and it has been evolved from focusing on flood control to now incorporating control for volume, erosion and water quality, which is theoretically based on a watershed concept.