Hydrologic design and water resources management approaches are evolving considering climate change and variability in many regions of the world. Water management agencies are responding to changing climate and variability by considering risk-informed or forecast-informed hydrosystem operations, deriving ad-hoc or long-term sustainable hydrologic design methods, adaptive management of water supply, and operations considering social–economic–environmental and energy system interactions. This chapter provides a brief overview of how methods of precipitation frequency analyses that are needed for hydrologic designs are being modified considering nonstationary climate and how water resources management approaches are coping up with the variability in water resources availability in space and time. Experiences from the U.S. are briefly discussed, and recommendations for adaptive hydrologic design and water resources management are provided.