Detention Tanks Research Articles

A Surrogate-Based Optimization Design and Uncertainty Analysis for Urban Flood Mitigation

This study proposes a surrogate-based optimization framework (SBO) to help analyze the tradeoff between flood damages and investment while considering uncertainty originating from surrogates. The surrogate models were constructed based on the relationship between drainage specifications and simulated flood information and used to replace the numerical model in optimization, thereby reducing the computational burden. The bootstrapping approach was employed to quantify the uncertainty originating from surrogate models, which were incorporated into the NSGA-II optimization algorithm to seek the interval of optimal solutions. Through a case study, the results showed that the uncertainties caused by surrogate models have a significant influence on the reliability of the optimal solutions, but require lower computational efforts. Moreover, the local design conditions (i.e., various designed rainfalls) had an impact on the design and performance of the detention tanks. The proposed framework will facilitate cost-effective planning of flood mitigation systems with an awareness of associated uncertainty in order to resolve tradeoffs, particularly for large-scale problems.

Sustainable Design of Urban Stormwater Drainage Systems by Implementing Detention Tank and LID Measures for Flooding Risk Control and Water Quality Management

With the increasing emphasis and application of the flooding control and mitigation measures of detention tank (DT) and low impact development (LID) in urban stormwater drainage systems (USDSs), the complex drainage flow process and corresponding water quality issues have also aroused great of interests and attentions from researchers and practitioners. This paper contributes to study the urban flooding control and water quality management with the implementation of DTs and LIDs in the USDS. A many-objective optimization (MOO) based design framework and analysis method is developed for achieving four objectives of USDS design. A realistic USDS is adopted for the case study, in which the DTs and LIDs are implemented by this extended MOO-based design method to achieve the optimal result of flooding risk control and water quality improvement. The obtained results are further analyzed for the characteristics of flooding risk control and water quality component evolution in the USDS. The results and analysis demonstrate the effectiveness and applicability of the designed DTs and LIDs to mitigate the flooding risk and improve water quality in USDS.

Simulação de implantação de um reservatório de detenção em uma rotatória em Palmas-TO, Brasil

A cidade de Palmas, capital do estado do Tocantins, foi a última cidade brasileira planejada do século XX, e foi pensada para crescer de forma organizada e racional, aproveitando de modo eficiente os serviços de infraestrutura urbana. Contudo, o crescimento da capital ocorreu de forma descontrolada. A urbanização desordenada da cidade deu origem a uma série de problemas de infraestrutura urbana. Palmas tem sofrido com as enchentes e, numa escala menor, com alagamentos, por conta do aumento do escoamento superficial e a cobertura de redes de drenagem deficientes. Dentre as medidas compensatórias apresentadas no Plano Municipal de Saneamento Básico do município está a implantação de reservatórios de detenção. O objetivo deste trabalho é analisar, por meio do Método de Puls, a eficiência na redução da vazão de pico à jusante decorrente da implantação de um reservatório de detenção na área de uma rotatória no Plano Diretor Sul de Palmas. O reservatório foi dimensionado na rotatória da avenida Norte-Sul-10 (NS-10) com a avenida Leste-Oeste-21 (LO-21) e a eficiência da implantação foi medida por meio do Método de Puls. O reservatório apresentou eficiência de 42,2% para o amortecimento da vazão de pico.

ARTIFICIAL RECHARGE FOR SUSTAINABLE GROUNDWATER MANAGEMENT PLAN IN YOGYAKARTA

<strong>Aim: </strong>This study investigates the development of a sustainable groundwater management strategy in Yogyakarta province through groundwater recharge technologies. This study also compares technologies used in the province and the one already implemented in Perth due to its similar nature in site geology and hydrogeology. <strong>Methodology and Results: </strong>Primary and secondary data were collected and analyzed. Water depth and hydraulic conductivity data were analyzed using permeameter and GIS program. GIS image analysis of water depth and hydraulic conductivity suggested that the placement of potential aquifer recharge sites would be best suited in the north-east part of the province, slightly outside the study area, to provide water for all. Two recharge schemes of an infiltration basin and an injection well with storm water detention tank were proposed. The injection well was decided upon, despite its higher cost, due to the impermeability of soils in Yogyakarta and possible water seepage to the environment. Similar to Perth’s Hartfield park scheme, an injection well would directly bypass these soil layers to recharge the aquifers with rainwater and storm water. Hartfield Park injects 4400 kL of water/year. <strong>Conclusion, significance and impact study: </strong>The findings of this study indicate aquifer recharge is a possible solution to overcome Yogyakarta’s high abstraction. Further studies recommend that injection well trials are further developed in terms of location, depth and sizing.

ARTIFICIAL RECHARGE FOR SUSTAINABLE GROUNDWATER MANAGEMENT PLAN IN YOGYAKARTA

Aim: This study investigates the development of a sustainable groundwater management strategy in Yogyakarta province through groundwater recharge technologies. This study also compares technologies used in the province and the one already implemented in Perth due to its similar nature in site geology and hydrogeology. Methodology and Results: Primary and secondary data were collected and analyzed. Water depth and hydraulic conductivity data were analyzed using permeameter and GIS program. GIS image analysis of water depth and hydraulic conductivity suggested that the placement of potential aquifer recharge sites would be best suited in the north-east part of the province, slightly outside the study area, to provide water for all. Two recharge schemes of an infiltration basin and an injection well with storm water detention tank were proposed. The injection well was decided upon, despite its higher cost, due to the impermeability of soils in Yogyakarta and possible water seepage to the environment. Similar to Perth’s Hartfield park scheme, an injection well would directly bypass these soil layers to recharge the aquifers with rainwater and storm water. Hartfield Park injects 4400 kL of water/year. Conclusion, significance and impact study: The findings of this study indicate aquifer recharge is a possible solution to overcome Yogyakarta’s high abstraction. Further studies recommend that injection well trials are further developed in terms of location, depth and sizing.

Impact of holding time on toxicity change of urban road dust during runoff process

During runoff process, the urban road dust (URD) passes through the road-side gutters and detention tanks, where it gets hold for a certain period of time, hours to weeks, before making its way into the water bodies. A part of the water-exchangeable toxicants are leached by the water, and some strongly bound toxicants remain attached to the URD. Toxicity of urban runoff is dependent on holding time, water volume, and the type and composition of the wet road dust (WeRD) and leachate. However, there are no studies that have elucidated the manner in which toxicities of the WeRD and leachate vary during prolonged holding in the runoff processes. The main objectives of this research were to, i) identify the distribution of toxicants in the WeRD and leachate, and ii) evaluate the change in toxicity during prolonged holding. The URD samples that were collected from residential road, arterial road and highways in Tokyo, Japan, were mixed with moderately hard water in varying ratios (1:2 to 1:16) and were held for a certain time (1h to 5days) before centrifuging into the WeRD and leachate. Toxicity test was conducted with ostracod Heterocypris incongruens direct contact test. Toxicity of both the WeRD and leachate from residential area was not significantly greater than the 20% lethal limit. Toxicity of the WeRD from other stations initially decreased, further reached a minimum corresponding to the critical holding time, and it subsequently increased again. Toxicity of the arterial leachate gradually increased, whereas that of the highway leachate gradually decreased during 5days holding. Unionized ammonia and zinc were confirmed as one of the possible toxicants. This study proposes and verifies a model for the toxicity change of the WeRD during prolonged holding.

Isotope hydrology and geophysical techniques for reviving a part of the drought prone areas of Vidarbha, Maharashtra, India

A multidisciplinary approach including environmental isotope (δ2H, δ18O and 3H), hydrochemistry and electrical resistivity tools were used to revive a part of the drought prone areas of Vidarbha region, Maharashtra, India. In this study, groundwater recharge processes, monsoon characteristics, climate variables during evaporation in the region were evaluated using environmental isotope techniques. Additionally, electrical resistivity surveys were also conducted to understand the aquifer geometry and weak zones (fractures, lineament) for the sustainable groundwater development. Significant seasonal variation observed in stable isotopic composition, deuterium excess and tritium in precipitation helped to delineate the sources of vapour generating the rains during both the southwest and northeast monsoons. A negative correlation between stable isotopic content and amount of precipitation is observed. Two sources of groundwater recharge, namely, natural recharge from precipitation and contribution from artificial recharge structures (detention tanks) were deduced. Hydrochemical data also corroborates the above findings. Environmental isotope data show that the groundwater is predominantly recharged from the southwest monsoon, and the contribution from the northeast monsoon is insignificant. Tritium data indicate that the groundwater is modern and its residence time is of the order of a few years. Modelling of evaporative isotopic enrichment helped in estimating the climatic variables such as temperature and humidity during evaporation. Also, the recharge from the detention tanks was quantified based on isotope balance model. Aquifer geometry and groundwater potential zones were delineated in a part of the study area using electrical resistivity method. An integrated approach of multidisciplinary techniques is found to be effective in assessing the recharge processes and groundwater potentiality in drought prone areas.

Exploring the performances of a new integrated approach of grey, green and blue infrastructures for combined sewer overflows remediation in high-density urban areas

Most sewage collection systems designed between 19th and early to mid-20th century use single-pipe systems that collect both sewage and urban runoff from streets, roofs and other impervious surfaces. This type of collection system is referred to as a combined sewer system. During storms, the flow capacity of the sewers may be exceeded and the overflow discharged into a receiving water body (RWB) through spillways without any control and remediation. Combined sewer overflows (CSOs) may, therefore, produce serious water pollution and flooding problems in downstream RWBs. Methodologies for a rational management of CSOs quantity and quality share many commonalities, and these two aspects should be considered together in order to maximize benefits and promote local distributed actions, especially in high urban density areas where the space availability for the construction of CSO storage tanks is often a limiting factor. In this paper, a novel strategy to control downstream flow propagation of a CSO as well as to improve its quality is tested on a real case study in the area of the metropolitan city of Milan. The approach is based on the combination of grey, green and blue infrastructures and exploits the integrated storage and self-depuration capacities of a firstflush tank, a constructed wetland and a natural stream to obtain admissible flow rates and adequate water quality in the RWB. The results, evaluated through a modelling framework based on simplified equations of water and pollutants dynamics, show excellent performances for the integrated system, both in terms of flow control and pollution mitigation. The pollution, using biological oxygen demand concentration as a proxy of the whole load, was decreased by more than 90% and downstream flooding situations were avoided, despite the spillway was not regulated. Concerning the economic point of view, from a rough estimate of the costs, the system allows reducing the investment of 30 to 50% in respect to the traditional CSO controls based solely on flow detention tanks. The proposed approach, as well as the modelling framework for its effective implementation, appear strongly scalable in different world contexts and aim to fill the gap between urban and rural environments in the management of stormwater and CSOs, promoting the involvement of the water managers, the irrigation-reclamation agencies and regional authorities.

Dimensioning of Required Volumes of Interconnected Detention Tanks Taking into Account the Direction and Speed of Rain Movement

This article is aimed at defining the impact of the direction and velocity of waves of rainfall as they pass over interconnected stormwater detention tank systems. The simulations were conducted for a real urban catchment area as part of the Storm Water Management Model (SWMM) 5.1 programme. The results permit us to conclude that the direction and velocity of a moving wave of rainfall have a significant influence on the required volumes of interconnected stormwater detention tank systems. By comparing the modelling test results for stationary rainfall and rainfall moving over the urban catchment area, it has been demonstrated that differences in the required volume of the detention tank located at the terminal section of a stormwater drainage system are inversely proportional to the adopted value of the diameter of the outfall channel for upstream storage reservoirs. In extreme cases, the differences may be up to several dozen percentage points. Furthermore, it has been proven that the arrangement of the stormwater detention tanks in relation to one another and the adopted diameter of the outfall channel are key factors in identifying the degree to which the detention tanks are hydraulically dependent on one another.

Sustainable technology for energy and environmental benign building design

A sustainable technology has been proposed to satisfy the total energy and gas demand for a building which can be produced by the building itself without any outsource connection. To satisfy the energy demand of 100% of a building some portion of its exterior curtain wall skin can be used as the black body acting PV (photovoltaic) panel to capture solar energy and convert it into electricity energy. The domestic waste including humane feces is proposed to be implemented into transforming process in site where sludge shall be collected into a closed anaerobic detention tank at cellar to introduce into a bioreactor; allowing to produce biogas (CH4) by Methenogenesis, then store, and utilize it for cooking and HAVC equipment. Then, the separated waste water to be collected and treated in site by applying all primary, secondary, and tertiary process and the treated water be used for gardening, and landscaping. Combined all these technologies simply would be an innovative field in sustainable science where a building can itself produce electricity and gas without any outsource connection to meet its total energy and gas demand which is benign to the environment.

An Analytical Stochastic Approach for Evaluating the Performance of Combined Sewer Overflow Tanks

AbstractStorm water detention tanks are widely used for the control of combined sewer overflows. Conventional continuous simulation and recently developed analytical probabilistic models have been used for analyzing the hydrologic operation of storm water detention tanks. These analyses are necessary in order to accurately estimate the runoff capture efficiency of a given control system or the required storage capacity for achieving a desired runoff capture efficiency. The analytical probabilistic models still have the shortcomings of making simplifying assumptions about the initial storage conditions of a detention tank. Developed in this study is a new stochastic analysis method which can provide similar results as provided by continuous simulations and overcome some of the shortcomings of the previously developed analytical probabilistic models. This stochastic analysis method uses closed‐form analytical equations to estimate the runoff capture efficiency and required storage capacity. Results from these analytical equations are validated by comparing with continuous simulation results and close agreements are observed. These analytical equations are therefore proposed as a computationally efficient alternative for analyzing the hydrologic performance of combined sewer overflow tanks.

Placement Strategies and Cumulative Effects of Wet-weather Control Practices for Intermunicipal Sewerage Systems

This study investigates the rainfall-runoff process and the pollutant dynamics on theoretical catchments and intermunicipal sewer systems in order to characterize the hydraulic and environmental performance of possible types of sewerage system and to compare the effectiveness of different wet-weather control schemes for intermunicipal sewerage systems. A comprehensive investigation on the placement strategies and the cumulative effects of wet-weather control practices is carried out over a broad watershed as a key preliminary step in addressing surface water safeguard requirements in developing and urban areas. The analysis shows that the different types of intermunicipal sewer system exhibit slightly different performance. Placing wet-weather detention tanks at different spatial levels affects the overall effectiveness of the wet-weather control system. In the examined case study schemes, the insertion of a wet-weather detention tank is better on final than on local flow regulators. The performance control also proves to be easier adopting the solution with intermunicipal tank since, for this scheme, the design criteria have a more important influence than rainfall characteristics on the environmental performance. These results represent an issue of primary focus for the implementation of environmental policies and mitigation strategies against surface water impairment in urban and developing areas.

A critical evaluation of the methods for the determination of required volumes for detention tank

Simplified methods allow a straightforward and quick determination of parameters of interest. A simplified method of calculation to be used must provide sufficiently accurate simulation results. This paper presents the results of tests completed to evaluate the effects of the parameters which describe a sewer catchment area and network on the value of Tp, a parameter applied in the Dziopak method [18]. The results of 2997 hydrodynamic simulations allowed to formulate an artificial neural network the application of which enabled the determination of the value of Tp dependent on the design parameters of a sewer catchment area and network. The artificial neural network had a very low error R2 = 0.9972 between the expected and determined values of Tp. The completed tests indicated a relationship by which an increase of the rainfall duration, a parameter used in the dimensioning of detention tank, is concomitant to an increase in the value of Tp. The calculations made so far included an assumption that the Tp value is constant irrespective of the design rainfall duration for the dimensioning of detention tank; this assumption has led to gross calculation errors. The paper also provides proof that the inclusion of these relationships allows a more precise determination of the service volume required for a multi-chamber detention tank.

Effectiveness of Runoff Control Legislation and Active, Beautiful, Clean (ABC) Waters Design Features in Singapore

Storm water management in Singapore has always been a challenge due to intense rainfall in a flat, low-lying and urbanised catchment. PUB’s (Singapore’s National Water Agency) recent runoff control regulation limits the runoff coefficient to 0.55 for developments larger than or equal to 0.2 ha. The use of Active, Beautiful, Clean (ABC) Waters design features are encouraged to attain peak runoff reduction. Hence the paper focuses on (i) determining the actual hydrological response regime of Singapore using the relationship between runoff coefficient (C), land use and slope; and (ii) investigating the effectiveness of ABC Waters design features in delaying and reducing peak runoff using a modelling approach. Based on a Storm Water Management Model (SWMM) model and using elevation, land use and soil data as inputs, the peak C-values were obtained for 50 m × 50 m grid cells. The results show that for the same land use, the one with steeper slope resulted in a higher runoff coefficient. Simulations were carried out in two study areas, Green Walk District and Tengah Subcatchment, where ABC Waters design features (such as porous pavements, green roofs, rain gardens) and detention tanks were incorporated to reduce C-values. Results showed that peak C-values can be reduced to less than 0.55 after increasing the green areas and constructing detention facilities. Reduction in peak discharge (22% to 63%) and a delay in peak discharge by up to 30 min were also observed. Hence, it is recommended to consider the relationship between slope and land use while determining runoff coefficients; and to incorporate ABC Waters design features in urban design to reduce the peak flow and runoff coefficient (C).

Evaluation of a first‐flush capture and detention tank receiving runoff from an asphalt‐paved road

AbstractIn this article, we propose and examine a first‐flush capture and detention tank (FCDT) working as a first flush capture device and pretreatment unit receiving stormwater runoff from an asphalt‐paved road. We design the FCDT to completely capture all the stormwater including a first flush generated by an initial 5 mm effective rainfall depth, and to bypass the exceeding part. According to our analysis based on the data from field monitoring and SWMM simulation for 27 events from April to June, 2015, the tank captured 35% of total runoff, which resulted in catching 74% of the TSS load. The TSS mass detention attained in this study by capturing the first 35% of the total runoff is close to the typical definition of a first flush, and also justifies the need for a first‐flush friendly treatment.

On the efficiency of stormwater detention tanks in pollutant removal

On the efficiency of stormwater detention tanks in pollutant removal

Compensatory alternatives for flooding control in urban areas with tidal influence in Recife - PE

ABSTRACT This paper presents a study of compensatory alternatives in urban drainage, using SWMM model (Storm Water Management Model), for the critical point of flooding in an urban area and vulnerable to tide fluctuations, located in Recife. For this, we used the registered information of the micro-drainage network and defined the parameters and variables required for modeling, such as: the subareas of contribution to the drainage system, indicating the percentage of soil waterproofing, equivalent width, slope, and infiltration rate; project rain; and tide curve. Two alternatives were simulated after the model has been calibrated. The first, which is an adaptation of the drainage network, presented maximum reductions in the volume of flooding of 37% for the events with recurrence period of two years and of 58% for five years of recurrence. The second, based on the deployment of a detention tank in the existing network, presented satisfactory results for the event of two years and reduced approximately 38% for events of five years. The results showed that there was a reduction in the area of flooding for the conditions simulated. However, the first alternative would not solve the local flooding problems, it would only attenuate and would increase the overload of the drainage pipes downstream of the modified system, while the second alternative could solve the problem of flooding, with the occurrence of an event of two years.

Flow characteristics of individual lot stormwater detention

In this paper the flow characteristics of stormwater are analyzed as it travels from a roof gutter down-pipe and the turbulent flow generated on entering an individual lot on-site stormwater detention (OSD) unit beneath a residential carport. Comparison was made between a full-scale model and computational fluid dynamic (CFD) simulations to determine the flow characteristics. These modular tanks with multi-unit chambers can capture the roof run-off from a 15-minute, 10-year return period storm. The results from the physical and CFD models matched well, suggesting that turbulent flow occurs when stormwater is directed to an individual lot stormwater detention tank. However, turbulence in the OSD was concentrated around the inlet, after which the pattern changed from turbulent to laminar flow. This work implies that the use of modular underground storage tanks is practical for managing stormwater from a roof.

Multi-Objective Optimal Design of Detention Tanks in the Urban Stormwater Drainage System: LID Implementation and Analysis

Under the influences of climate change and rapid urbanization, extreme rainfall events become more and more intensive and the urban flooding issues have been frequently faced in many cities in the world. Previous practical and scientific experiences have demonstrated that appropriate utilization of detention facilities and low impact development (LID) devices for urban region design could be important and effective ways to the flooding control and drainage service management of an urban stormwater drainage system (USDS). This paper investigates the optimal design and application of detention tank network and LID devices for achieving these multiple objectives in the USDS. The framework and method of LID-based multi-objective optimal design of detention tanks in USDS is first developed in this study, and a practical case in SA city of China is then taken for the application. The results of this study confirm the feasibility and validity of the proposed methodological framework for the LID-based multi-objective optimal design of detention tanks in the USDS. Specifically, both total investment costs and flooding risk have been greatly reduced by the optimal implementation of the detention tank and LID measures. Meanwhile, the results indicate that the LID devices may have global effect to the flooding control and the detention tanks can be locally efficient to reduce the flooding risk. Finally, the findings of this study are discussed in the paper for their practical implications to the practical design and management of USDS.

Multi-objective Optimal Design of Detention Tanks in the Urban Stormwater Drainage System: Uncertainty and Sensitivity Analysis

Design of detention tanks becomes important to the flooding control and drainage service management of an urban stormwater drainage system (USDS). While the hydrological and hydraulic models and methods have been widely developed in the literature for the optimal design and management of USDS, there is not yet a general methodological framework that is applicable for all practical systems. This is mainly because of various complexities in practical USDS, such as different design objectives (i.e., multi-objective design) and local design criteria and policies, as well as variety of inevitable uncertainties in the system. Previous work by the authors has focused on the first two aspects, in which a viable design framework has been developed and applied for multi-objective optimal design of detention tanks in the USDS under conditions of different local design criteria; and this paper deals with the third factor, aiming to explore and extend further the optimal design methodological framework to USDS with uncertainties. A real-life USDS in China is applied for this investigation. Uncertainty analysis is firstly conducted to characterize the importance of different uncertainty factors considered in the studied system. The uncertainty analysis result is thereafter incorporated into the previously developed multi-objective optimal design framework, in which the Monte-Carlo simulation method is adopted for the stochastic process investigation. The case application and analysis indicate different influences of uncertainty factors in the system to the multi-objective design results of detention tanks (total cost and flooding risk) in the studied USDS. The results and findings of this study are also discussed in the paper for their practical implications to the design and management of USDS.