When designing flood risk management plans, civil engineers typically consider factors such as the likelihood and frequency of flooding in the area, potential flood sources, and the potential impact on people and property. They then use this information to evaluate different flood risk management options and develop a plan that includes measures such as flood mapping, early warning systems, flood walls, and levees, as well as non-structural measures such as land use planning, evacuation planning, and public education. The ultimate goal is to minimize the potential harm caused by floods while also considering economic and social factors, such as the cost of implementing the plan and the impact on local communities.