Author(s): Myagmarsuren Bat-Erdene; Oyunbaatar Dambaravjaa; Dorjsuren Dechinlkhundev; Munkhtsetseg Zorigt; Badarch Khasbaatar
Linked Author(s):
Keywords: Rainfall flood; Gobi region; Velocity; Mongolia; Rainfall intensity
Abstract: More than 60% of Mongolia’s territory is arid and water scarce areas with no surface water. Hence, groundwater is the main source for developing sectors such as mining and industry as well as other sectors in the Gobi region of the country. However, water resources from different sources need to be utilized especially surface water that occurs during short periods of heavy rainfall in the region. Therefore, in the absence of climatic and hydrological observational data in this region, it is crucial to estimate the maximum rainfall discharge for different return periods. Rainfall patterns, intensity and geo topographical conditions are the main factors for the estimation of heavy rainfall runoff. Mean annual rainfall in study area varies between 94.4 mm and 130.1 mm and 92.5% of annual rainfall falls during the summer season. Evaporation form water is higher than other areas reaching 1000 mm. This study aims to estimate the rainfall maximum flood along the small creeks and dry beds in the Gobi region of southern Mongolia, Umnugobi province. The catchment area of the selected creeks and dry beds varies from 0.4 to 95.2 km2 with the length of 17.9 km. Filed surveys were carried out on 35 dry beds and morphological and cross-sectional data were measured. Flow velocity was estimated through the Chezy-Manning, Golubetsov’s method and the rainfall intensity empirical methods. The estimated flow velocities were validated with the observed data. The Pearson correlation coefficient was 0.9 and standard error was defined as 0.06 m/s. It is concluded that the Golubetsov’s method is proper to for pebbles. The maximum flood discharge with 100-year return period is estimated by the method of “Rainfall intensity method” adopted for Mongolian condition and applied for small rivers with catchment area of less than 200 km2.
Year: 2024