16. Study of Rising Surface Water Levels on Land Submergence and Groundwater

Floods are most commonly caused by severe rains when natural watercourses fail to handle the excess water. They are not necessarily produced by excessive rainfall. There are many factors that can lead to floods, including storm surges associated with tropical cyclones, tsunamis, or high tides associated with higher-than-normal river levels, and especially in coastal areas, floods can occur due to a storm surge from a tropical cyclone, a tsunami, or a high tide and high river levels. Even in dry weather, dam failure, such as that induced by an earthquake, will result in downstream flooding. Other elements that might cause flooding include rainfall volume, intensity, and duration, spatial distribution; the capacity of a stream network to convey runoff; and catchment and weather conditions previous to a rainfall event, terrain, ground cover, and tidal forces. So for potential flooding sites, drainage network information must be known. The rivers, canals, water streams, etc., make a great network of drainage system. For any site, drainage network can be extracted with the elevation information. The elevation information is contained in DEM (Digital Elevation Data) data which you different sources and applying hydrological analysis, we can extract drainage network. Using a digital elevation model, a hydrological analysis was performed to determine the slope, flow direction, flow accumulation, and drainage network. The purpose of this study is to examine the boundaries of the Lucknow Municipal Corporation (LMC) in order to construct and test a GIS-based flood inundation map. DEM and drainage network information is further employed to assess the potential flooding sites in the Lucknow city, and the potential flooding sites are investigated starting from 107 to 122 m with an increment at 1 m interval. The results of this study show that at 110 msl total potential flooding area is approximately 23.75 km² and at 122 msl total potential flooding area is 133.35 km² are estimated.