Rains in the Mojave Desert region are intense and result in the destruction of property. This destruction is significant and affects development plans in the area. Joshua Tree National Park (JTNP) is one of the areas affected as a result of flash floods in the Mojave Desert region. As part of the efforts to minimize the effects caused by flash floods in the park, there was a need to carry out a hydrological analysis of surface runoff in order to map out high risk areas that are susceptible to floods after Monsoonal rains, identify areas in the park that require diversion berms, and establish the effectiveness of the existing diversion berms. The analysis result was a 3D topographic model and a map that contains high flood risk areas and potential areas where diversion berms may be constructed to divert surface runoff and protect the park’s infrastructure.