Potential Impact of Land-Use Changes on River Basin Hydraulic Parameters Subjected to Rapid Urbanization

Abstract

Urbanization is a significant challenge that catchments face around the world leading to difficulty in implementing stormwater-related engineering solutions. This study aimed at investigating the impact of land use/land cover change on hydraulic parameters of a rapidly urbanizing river basin, a case of the Jangwani basin in Dar es Salaam, Tanzania. In this study, the peak discharges were estimated using the SCS-Curve Number Method under the combination of ArcGIS and HEC HMS for three different years (1998, 2009, and 2018). The 100-year rainfall event recorded in 2011 was used to develop the meteorological model in HEC HMS. The steady flow analysis was accomplished using the HEC-RAS software package. To capture the effect of land use/land cover change as well as avoiding variability, the same rainfall dataset was applied for all the three study years. According to the modelling results in HEC RAS, the parameters such as top flow width, average velocity, hydraulic depth, conveyance, shear, stream power as well as the cumulative volume were observed to be increasing with time.