Introducing leaky-well concept for stormwater quantity control in Dhaka, Bangladesh (original) (raw)
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Climate change will affect water resources through its impact on the quantity, variability, timing, formation and intensity of precipitation. Improved management of storm water is critical, if addressed inadequately, it will jeopardize progress of poverty reduction targets and sustainable development in all economic, social and environmental dimensions. The purpose of this drainage study is to assess the present drainage situation, identify the future requirements and suggest improvement of the drainage network system to provide the Municipality a area free from water congestion within an acceptable environmental condition. Integrated study of drainage dynamics in consideration of gravity flow for the proposed drainage improvement system is made by developing rainfall-runoff model and analytical computation for the urbanized area. The overall planning processes are conjugated with rigorous study of infrastructure, Digital Elevation Model (DEM), land-use and sattelite image using GIS for a preliminary conceptual understanding of the Municipality system; identification of rivers/khals* surrounding the Municipality and collection of data to understand the hydrological response of the Municipality; assessment of effective range of land levels which would be considered for planning process; making of intensive field visit for identification of possible outfalls and drainage routes in verification of the preceding planning processes; planning of drains & zones with scrutinized outfall locations; and finally storm runoff assessment using empirical formula. Modelling approach is used to generate catchment runoffs which are calibrated against flows using empirical formula known as modified rational formula for respective design year.
Journal of Engineering Science, 2024
Khulna City Corporation (KCC), located in a low-lying area in southwestern Bangladesh, has been suffering from frequent water logging in the rainy season almost every year. This situation is intensified due to rapid urbanization and the impact of climate change, which have consequently created numerous problems in KCC related to stormwater management issues that require immediate consideration. Therefore, the current study aims to explore stormwater management problems in KCC and find possible countermeasures through different best management practices. Stormwater management must be incorporated into urban design and development, particularly in densely populated urban areas like KCC. In Ward No. 30 of KCC, controlling stormwater is a vital concern due to heavy rainfall, a lack of proper drainage infrastructure, unplanned growth, extensive land cover areas, etc. In the current study, the most widely used Personnel Computer Storm Water Management Model (PCSWMM) software was adopted to evaluate the city's current stormwater management practices and develop a long-term stormwater management strategy. A reconnaissance investigation of the existing states of the soil, drainage, and outlet infrastructures was conducted. The study area (KCC Ward No. 30) was then divided into many small catchments in the ArcGIS platform, and areas of each sub-catchment were identified. To determine the percentage of impervious area and the elevation of the study area, the land use and land cover (LULC) map and the digital elevation model (DEM) were generated using the ArcGIS software. All the aforementioned parameters were then entered into the PCSWMM software, and simulations were performed for various rainfall durations using different best management practices. The PCSWMM simulation provided the results of runoff, infiltration, peak runoff, floods, or surcharges at every drainage node or discharge point in the existing and altered drainage system of the study area due to the occurrence of extreme rainfall. The results indicate that various best management practices, increasing the slope, reducing the roughness of the drainage systems, reducing imperviousness, permitting more infiltrations, and promoting green infrastructure, are highly effective in controlling urban flooding or surcharges in the study area caused by the occurrence of extreme rainfall in the future. The findings of this study are expected to be supportive to policymakers, urban planners, and water managers in implementing and promoting sustainable and climate-resilient urban drainage infrastructures to tackle stormwater management problems in the KCC area.
Design of Storm Water Drainage System in A Metropolitan Area
International Journal of Engineering Research and, 2020
A scientific drainage system to catch the storm water is a long term need of the society, particularly in cities. Urbanization along with its impermeable structures is one of the major causes of flooding in metropolitan areas. The rainfall intensity and characteristics of catchment area are the major factors for designing metropolitan storm water drainage facilities. These facilitates have a uppermost advantage to safely dispose the generated floods to receiving system. Many towns lack in providing proper drainage system. The present design helps the rainfall in design storm water drainage system. Past record of 34 years rainfall data has been taken for study. Various methods were reported in literature for runoff estimation. In the present study, rational method has been used for estimation of storm water runoff which is widely reported in literature. The present study is to estimate runoff of a drainage basin and also to design as a case study for Navrangpura Area in Ahmedabad, Gujarat where the design is based on different velocities .
Drainage network optimization for inundation mitigation case study of ITS Surabaya
AIP Conference Proceedings, 2017
Institut Teknologi Sepuluh Nopember (ITS) Surabaya is one of engineering campus in Surabaya with an area of ± 187 ha, which consists of building and campus facilities. The campus is supported by drainage system planned according to the ITS Master Plan on 2002. The drainage system is planned with numbers of retention and detention pond based on the city concept of Zero Delta Q concept. However, in the rainy season, it frequently has inundation problems in several locations. The problems could be identified from two major sources, namely the internal campus facilities and external condition connected with the city drainage system. This paper described the capabilities of drainage network optimization to mitigate local urban drainage problem. The hydrology-hydraulic investigation was done by utilizing the Storm Water Management Model (SWMM) developed by US Environmental Protection Agency (EPA). The mitigation is based on several alternative that based on the existing condition and regarding the social problem. The study results showed that the management of the flow from external source could reduce final stored volume of the campus main channel by 31.75 %.
IJERT-Design of Storm Water Drainage System in A Metropolitan Area
International Journal of Engineering Research and Technology (IJERT), 2020
https://www.ijert.org/design-of-storm-water-drainage-system-in-a-metropolitan-area https://www.ijert.org/research/design-of-storm-water-drainage-system-in-a-metropolitan-area-IJERTV9IS060757.pdf A scientific drainage system to catch the storm water is a long term need of the society, particularly in cities. Urbanization along with its impermeable structures is one of the major causes of flooding in metropolitan areas. The rainfall intensity and characteristics of catchment area are the major factors for designing metropolitan storm water drainage facilities. These facilitates have a uppermost advantage to safely dispose the generated floods to receiving system. Many towns lack in providing proper drainage system. The present design helps the rainfall in design storm water drainage system. Past record of 34 years rainfall data has been taken for study. Various methods were reported in literature for runoff estimation. In the present study, rational method has been used for estimation of storm water runoff which is widely reported in literature. The present study is to estimate runoff of a drainage basin and also to design as a case study for Navrangpura Area in Ahmedabad, Gujarat where the design is based on different velocities .
Frontiers in Hydrology Meeting 2022, 2022
Rapid population growth in Bangladesh has led to an increase in the rate of urbanization across the country. Runoff is increased due to an increase in impervious surfaces as a result of urbanization. Sylhet City Corporation (SCC) is a metropolitan city in northeastern Bangladesh that is frequently afflicted by urban flooding and waterlogging as a result of storm runoff due to heavy rainfall. A substantial portion of the city suffers from severe drainage congestion, which is caused by the inadequate drainage system, lack of maintenance of drainage system, garbage dumping in the drains and canals, and illegal encroachment of drainage canals. The review of the existing drainage system and the causes of the drainage congestion in the city area have been assessed in this study. This study also focuses on the stormwater management of Goali chhara sub-system of eastern part of Sylhet City Corporation which is responsible for waterlogging in the study area. The Goali chhara sub-system has been modeled using GeoSWMM to analyze the stormwater runoff and to prepare a masterplan of drainage network considering the climate change issues. The design water level of the Surma river has been estimated from historical river water level data using the Gumbel distribution method. Moreover, analyzing the historical rainfall data of Sylhet Station, the IDF curve for short-duration rainfall has been developed and the design rainfall intensity of 2-hour and 5-year return period has been estimated. These hydrological parameters have been used in the model and prepare the drainage network masterplan. The model has been calibrated using the estimated runoff coefficients from the land use map for the sub-catchments. The stream cross-sections for the 10-year return period were found to be larger than that obtained for the 5-year return period. This research will help the local authorities of Sylhet City Corporation by allowing them to make drainage capacity expansion decisions that will tackle this critical challenge for the next 30-40 years.
Water Sensitive Urban Design: Dhaka City
Water is both a blessing and a blight for Bangladesh, a riverine country that lies on a delta plain formed by the Himalayan rivers and borders the Bay of Bengal. Straddling the Tropic of Cancer, the country is characterized by heavy seasonal rainfall during the monsoon. Flash floods are common all over the country including Dhaka, the capital city. Rapid urbanization of the city has deteriorated the flooding conditions even more. Industrialization, urbanization and expanding populations, on the other hand, have resulted in over-extraction of groundwater which cause the city to face serious water shortages. This paper aims for a water sensitive urban design for Dhaka city which can meet the city's water demand whilst mitigating the water logging. It provides an overview of various storm water infrastructures that include the innovative concept of storm water collection, treatment and re-use plan with successful examples from different cities. The paper then proposes possible strategies along with restoration opportunities within the urban landscape of the city of Dhaka.
Modelling the impact of design rainfall on the urban drainage system by Storm Water Management Model
Journal of Water and Land Development
Flood modelling is an effective way to manage the stormwater network in cities. It aims to understand and predict the behaviour of stormwater network so that it can test and evaluate effective solutions to structural and operational problems. So simulation modelling stays a preoccupation for building a successful hydraulic modelling in urban areas. This study investigates the impact of the design rainfall on the hydraulic modelling results for the Azzaba stormwater network located in the North-East of Algeria by using the Storm Water Management Model (SWMM). Four scenarios of design rainfall events were compared for 10, 25 and 50-year return periods, where we used double triangle and composite curves for the design rainfall event definition. The results show the impact of the choice of design rainfall on the behaviour of the stormwater network, from which the results of simulation by the double triangle method for the short durations represents a great risk on the probability that t...
A Review of Recent Studies on Urban Stormwater Drainage System for Urban Flood Management
2020
Stormwater drainage and urban flooding are the popular issues in policy agendas and academia. Although the research on these title increases steadily an integrated review on stormwater drainage and urban flood with a focus on pluvial flooding has yet to be produced. This paper presents a critical review on stormwater drainage and urban flood based on 78 selected journal papers published over the period of 1990 to 2018. The review focus on pluvial flooding to relate urban stormwater drainage management and urban flood disaster management and to show the links between the two. The methods taken to manage urban stormwater drainage and urban flooding as well as the complexity of achieving a comprehensive urban flood disaster management are evaluated and discussed. To better understand the concepts behind urban flood and improve the urban flood risk management strategies, recommendation of future research directions are also provided.
Climate change will affect water resources through its impact on the quantity, variability, timing, formation and intensity of precipitation. Improved management of storm water is critical, if addressed inadequately, it will jeopardize progress of poverty reduction targets and sustainable development in all economic, social and environmental dimensions. The purpose of this drainage study is to assess the present drainage situation, identify the future requirements and suggest improvement of the drainage network system to provide the Municipality a area free from water congestion within an acceptable environmental condition. Integrated study of drainage dynamics in consideration of gravity flow for the proposed drainage improvement system is made by developing rainfall-runoff model and analytical computation for the urbanized area. The overall planning processes are conjugated with rigorous study of infrastructure, Digital Elevation Model (DEM), land-use and sattelite image using GIS for a preliminary conceptual understanding of the Municipality system; identification of rivers/khals* surrounding the Municipality and collection of data to understand the hydrological response of the Municipality; assessment of effective range of land levels which would be considered for planning process; making of intensive field visit for identification of possible outfalls and drainage routes in verification of the preceding planning processes; planning of drains & zones with scrutinized outfall locations; and finally storm runoff assessment using empirical formula. Modelling approach is used to generate catchment runoffs which are calibrated against flows using empirical formula known as modified rational formula for respective design year.