URBAN FLOOD MODELLING: A CASE STUDY OF WAZIRABAD, GURUGRAM

Abstract

One of the Global challenges in this 21st century is to manage the runoff in an urban area. Now, in this day urban development is leading to changes in local hydrology and streams of the runoff. The impervious surface in the urban area is leading to a high volume of runoff with high peak discharge. It also takes a short period of time to reach the mainstream with A higher volume of pollutants. There are lot of factors responsible for urban flooding. An increase in population and development work that's lead to more urbanization, a decrease in infiltration and larger peak discharge and runoff. This thesis describes the concept, idea and operation of urban flood disasters. Every year urban flooding occurred in many parts of Gurugram, motivation for doing work on this topic is to solve this problem. First, we will try to understand the cause of urban flooding. Whether it is due to change in land use or due to climate variability. A Hec-Hms model set-up is done for the Gurugram Wazirabad area and conducts the simulation using rainfall grid data. HEC-RAS set-up is done to see the inundation area after the event. Image analysis is done using SNAP software to see the difference before the flood and after the flood. The use of GIS tool is very useful in this work. The results show that there is a huge increase in built-up area from 2016 to 2021. There is an increase in built-up area by 35.34 % and the vegetation is decreased by 26.18 %. The result in Hec-Hms shows that the discharge in 2016 was 6.5 cumec while in 2021 it was 9 cumec. Due to an increase in built area by 35.34 %, there is an increase in discharge by 38.46%. Accumulation of water is seen at junction J1_1, J2_1, Sink-1, and in SB-18, SB9, SB 7, SB1,1, and SB22. There are 16 sub-basins in our catchment. Appropriate Flood Mitigation measures should be implemented to reduce the impact of urban flooding. Sector 14, Sector 15, Sector 17, Sector 31 , Phase-1 , DLF area , Golf Course Road ,IFFCO Chowk and Sheetla Mata Road are among the most severely impacted region. Some of the mitigation measures are the Construction of Check dams, the Improvisation of Drainage Infrastructure, and the Diversion of Runoff into Wazirabad lake. After Making the check dam the, retention time of the runoff decreases thus accumulation of water will not take place. An increase in the Carrying capacity of the drain will help in reducing the water-logging issue. Diversion of runoff into Wazirabad lake will help runoff to continuously flow that which will reduce the accumulation of water.