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Matara Municipal Council area had been experiencing stormwater drainage problems causing inconvenience to public, interruption to work and damage to property. Though the Matara Municipal Council (MMC) had carried out a project in 2001 to develop its drainage canals, there were many cases of flooding within its boundary limits. In order to achieve a...
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... Overall methodology used for the plan preparation is schematically shown in Fig. 2. Data was collected to capture the background to the problem and also to perform a situation assessment [3]. A brief methodology and list of activities carried out to achieve the specific objectives are as indicated below: ...
Urban flooding is a manmade disaster. Increased surface imperviousness due to urbanization along with encroachments of nalas and waterbodies and inadequate drainage infrastructure system are the chief culprits for urban flooding. Flooding in an urban area brings about severe economic, structural, and environmental damages, and can be associated with casualties too. The current paper illustrates the role of GIS technology in urban drainage mapping and analysis. It identify the pre-disposing factors that lead to urban floods and explains the effect of each factor on urban floods, the trend and relationship to each other. The flooding in some areas of GHMC during September 2016 came as a grim reminder of the unprecedented Musi floods of 1908 and the recent floods in August 2000. There are about 403 different waterbodies like tanks/lakes/reservoirs in GHMC areas as identified from the Survey of India toposheets on 1:25,000 scale. Alarmingly, only a minuscule 169 lakes have a water spread of over 10 ha, an indication of how intertwined political and real estate ambitions have dealt a death blow to many waterbodies. To address city’s problems, especially inundation of areas, remodelling of storm water drains (nalas) and identifying the obstructing structures on nalas and lake beds, Remote Sensing & GIS technologies are effective tools. The majority of GHMC area is drained by Musi river catchment. The Digital Elevation Model (DEM) of the entire drainage basin of GHMC is prepared using cartosat data and micro watersheds are also delineated. The daily surface runoff is calculated during the flood days using Automatic Weather Stations (AWS) rainfall data. The natural drainage course is identified from the Survey of India Toposheets on 1:25,000 scale and it is compared with Revenue and Urban parcels data to find out the encroachments and bottle necks in drainage course. The required nala widths are calculated by making use of hydrological parameters. Finally a model storm water plan is developed by making use of existing nala widths to overcome the flood menace in GHMC. Hence Geospatial technology is an effective tool in mapping and analyzing the spatio-temporal data and to inform the stakeholders and decision makers of the locations in controlling flooding and improve decision making. © 2019, Springer International Publishing AG, part of Springer Nature.
... Available data from already published reports and collection agencies were collected in order to obtain flood, terrain and hydrologic characteristics of the study area [7]. It was noted that other than regional rainfall and catchment characteristics there were no hydraulic or hydrologic data pertaining to the study area. ...
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Diversion of surface runoff from housing allotments directly into stormwater drainage network along roads is a common phenomenon in urban areas which leads to the urban flooding. When urban land changes are made for development, the natural hydrology undergoes changes usually leading to high surface runoff and often flash floods. Calculating the effect of modifications and quickly proposing an optimum solution becomes a difficult task not only to non-technical persons but also to some technical persons. Screening of existing tools identified that there is no single tool which could dynamically capture the land modifications and perform hydrological calculations to manage stormwater from urban lands. Main objective of the present research was to develop a dynamic user-friendly GIS tool which would capture key land parcel changes and perform calculation of stormwater generation by looking at both pre and post development scenarios. Accordingly a user friendly Dynamic GIS tool which enables on-screen modification of a land allotment was developed for computation of a composite land parcel runoff coefficient. Then the tool was extended to incorporate a hydrologic model to perform a comparison of before and after modification and then to extend the tool for incorporation of a detention tank model for management of generated stormwater. Thimbirigasyaya ward of the Colombo Municipal Council area in the 162 hectares having 1405 land parcels was the study area. The development methodology included, requirement identification, literature survey, conceptual design, coding, testing, modification and product delivery. In the conceptual design, the tool design was carried out for land authorities to optimize development alternatives jointly with the owner. Therefore the tool demanded a high level of user friendliness. Through a detailed literature survey, soil, slope and Landcover were identified as the key parameters governing stormwater generation from a land parcel modification. Hydrologic modeling computations within the tool were based on the rational formula, unit hydrograph theory and tank model concept. Detention storage for stormwater management was based on the research monograph of Wijesinghe and Wijesekara (2010). Split, merge and adjust operations were incorporated to the tool to carryout land modifications. Summative and formative evaluation techniques were used to achieve user-friendliness and accuracy of the tool. A lookup table cited in Perera & Wijesekera (2010) for runoff coefficient computation was embedded in the tool. Tool is capable of following modifications to this lookup table as and when new research findings are known. In the land modification component the tool facilitates on-screen modifications of land parcels and updating of hydrological parameters. GIS model combines the layers and supporting data such as runoff coefficients, rainfall etc to compute the time series of stormwater generated from each land.
Tool developed by the present work develops a hydrograph and permits a user to incorporate dimensions of a detention pit to observe its effect on stormwater generation. This enables a land owner and a manger to identify a suitable detention pit for the intended land modifications. Unavailability of Graphic User Interface (GUI) guidelines for GIS and the lack of suitable spatial data security algorithms that could be used with confidence, influenced the present work to contribute and develop new techniques. As main results of the work, a user friendly accurate dynamic GIS tool, capable of land management in relation to stormwater, a step by step user manual, guidelines for GUI development and contributions towards security algorithm could be mentioned. Visualization of land modifications; dynamic change capability of parameter selection, design rainfall and detention pit sizes; and visual presenting the effect of detention pit incorporation are unique features of the tool which increases the user friendliness for non-GIS decision makers. The development of a single tool which provides Hydrologic-GIS capabilities for urban property management activities through the capabilities of identify optimum solutions is a contribution towards successful GIS applications for land and water management. Due to the possession of “Muscle” to rationally manage urban land parcels, the name “Geographic Information Systems to Manage Urban Stormwater Considering Land Enhancement” abbreviated as “GIS2MUSCLE” is given to the tool contributed from the work. This study through development and testing, satisfactorily concluded that a user friendly dynamic GIS tool enabling on-screen land and attribute modifications had been developed to user satisfaction while achieving 100% accuracy. Developed tool which enables the visualization of prior and post scenarios of land development has the capabilities to successfully handle the dynamics of both stormwater generation and process of land management. Present work also concluded that in order to achieve user friendliness and user satisfaction, it is necessary to incorporate an iterative design process with careful consideration of visual clarity, consistency, compatibility, informative feedback, explicitness, appropriate functionality, flexibility and control, error prevention and correction, user guidance, user support etc., with respect to tool development.
In the era of sustainable development of smart cities, Remote Sensing and GIS is playing a key role in the development and transforming of ordinary cities into smart cities. One of the major objectives of this research work was for the people facing various problems related to improper drainage, sewer, storm water management thereby providing a better infrastructure for living. Here, in this study a storm water management layout plan was prepared using the techniques of Remote Sensing and GIS to mitigate the impact of flash rain as a result of climate change in a part of Aliganj, Lucknow. The results of this study will be beneficial for future urban planning and development of sustainable storm water management layout plan by the various governmental agencies.
