This study covers the investigation of the flood mitigation measures required to protect the city of Baledwayne, which is located in the Hiran region of Somalia and has been subject to frequent floods recently. In the HEC-HMS model, the precipitation data measured in 2019 and DEM at the Baledwayne and Bulo-Burti stations of the Hiran region were used as input. The observed discharge in the Shabelle river in 2019 of both stations was imported into the model to compare the simulated rainfall-runoff hydrographs. The rainfall-runoff hydrographs of 2019 were simulated with the HEC-HMS model using these parameters, SCS Curve Number for analyzing runoff volume, Snyder Unit Hydrograph for estimating direct runoffs, and Constant Monthly for calculating the baseflow and Muskingum for channel routing. The outflow hydrographs at both stations were successfully simulated. With the 1D&2D HEC-RAS model, flood maps were generated using various alternatives to protect the study area from floods of Q500 flow rate with a return interval of 500 years. The Deyr 2019 flood event was used for the calibration of the model. The model determined the flood extent and depth of this flood event by changing the roughness coefficient at specific intervals. Various flood mitigation measures have been investigated after calibration. It has been found that the best protection can be achieved by the combination of these four flood mitigation measures: (1) rehabilitation of the Warabole diversion channel, (2) construction of detention ponds at the upstream of the floodplain, (3) levees along both sides of the river and (4) improvement of the river.