Seng Theara creator Sutat Weesakul Chairperson Babel, Mukand Singh Examination Committee Duc Hoang Nguyen Examination committee Somchai Chonwattana Examination committee Deutscher Akademischer Austausch Dienst (DAAD), Germany Scholarship donor Asian Institute of Technology Fellowship Scholarship donor text series technical report th Pathum Thani, Thailand Asian Institute of Technology 2018 continuing eng 1 online resource (101 leaves) : ill. (some col.) + 1 online resource The urban drainage system is an indispensable water infrastructure to carry out the stormwater resulting from the runoff in all cities around the world. Most large-scale urban drainage systems have been designed under the stationary conditions of land use and climate. Recent studies have indicated that the trend of intensity and frequency of extreme rainfall tends to increase as the results of climate change. So far, the cities will face more chance of frequent inundations due to the heavy rainfall and lack of drainage capacity. Hence, the study on existing urban drainage system becomes more challenged and urgent. In general, the modeling techniques have been applied in order to research in this area. The study focuses on the primary drainage system in the Eastern Bangkok Metropolitan area which has a rapid change in land use than other areas. It highlights the performance of existing urban drainage system corresponding to the heavy rainfall events in both present and future as well as the effectiveness of a newly added tunnel structure. MIKE 11 model is used to simulated the hydraulics in drainage network from three high rainfall events in 2013, 2016, and 2017. Based upon observed water level and recorded rainfall data, it was found that existing primary drainage system was still able to cope with heavy rainfall events with the intensitiesareapproximately90mm/day. The observed water levels in canals rose up quickly after the heavy rainfall happened in the city. The peak water level did not exceed the canal banks. The Bang Sue tunnel constructed at the northern part of the city has provided an effective flood reduction while the daily rainfall intensities was148 mm. It can reduce the peak water levels 78% to 15% depending on the distances from its pumping station (0 {u2013}13 km follow the canal line); likewise, the recession time to bring the water level back to its water level control plan would be 6 to 14 hours reduced respectively. Without tunnel, water level in Bang Sue canal overbank flow with 8,000 m. Therefore, tunnel shows highly beneficial for large scale urban water management. The return period of the 3-hour rainfall on 14 October 2017 was considered to be 5 years and its intensities will expect to change by 20 % in the near future (2015 {u2013}2039), which causes the peak water levels to increase remarkably at various locations along the canals in the city core from 10.0 to 28.4 cm equivalent to10% and40%.The area along Samsen canal was found to be the most vulnerable due to the overbank flow. However, there is no significant increment in water levels at the northern part where the new tunnel is operated. This can be inferred that the tunnel will effectively handle the inundation problems with the change in IDF of extreme rainfall in the future. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management Thesis (M.Eng.) - Asian Institute of Technology, 2018 Urban drainage Thailand Bangkok Runoff Thailand Bangkok Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B04677 http://203.159.5.9/ait-thesis/detail.php?q=B04677 200820 20260818145235.0