Paper Title
STREAM FLOW SIMULATION IN URBAN AREA OF MANDALAY

Abstract
Urban flooding in Mandalay is longstanding, exacerbated by rapid urbanization and inadequate infrastructure. This paper aims to simulate stream flow in Mandalay using HEC-HMS 4.7.1 model integrated with ArcMap 10.5. The urban area of Mandalay were delineated using Digital Elevation Model (6-meter resolution). The curve numbers (CN) for Mandalay were calculated based on soil and land use maps (2012-2022). 33 years of daily rainfall data (1990-2022) at four stations (Mandalay, Amarapura, Patheingyi, and Pyin Oo Lwin) were collected for frequency analysis. The estimation of rainfalls with different return periods are evaluated by performing frequency analysis using chosen best-fit Gumbel parameter estimation method and ensuring accuracy through diagnostic test. Mean aerial rainfall over the study area is calculated by using Thiessen Polygon method in ArcMap 10.5. Rainfall Depth Duration Frequency values were subsequently used as inputs for the frequency storm method in HEC-HMS. The SCS curve number, SCS unit hydrograph, Muskingum routing method and recession of baseflow method were applied to simulate stream flow and calibrate in HEC-HMS. The average percent difference of three outlets is 2.8%, indicating overall satisfactory performance of the simulation model to predict the peak flows, which signifies the HEC-HMS model’s suitability for accurately simulating stream flow rates in Mandalay, thus facilitating effective flood risk assessment and management. Keywords - Daily rainfall, HEC-HMS model, Mandalay, SCS-CN, Stream flow simulation, Urban flooding