The Petit Jean watershed (HUC 11110204) covers an area of approximately 1,572 square kilometers in north-central Arkansas. The watershed is characterized by rolling hills and valleys, with the Arkansas River flowing through the western portion. The hydrology of the watershed is influenced by seasonal precipitation, with the majority of flow occurring in the spring and fall. The area receives an average of 117 cm of precipitation per year, with snowfall being rare. Surface water in the watershed is important for recreational activities such as fishing and boating, and is used for drinking water supply and irrigation. Reservoirs in the watershed include Nimrod Lake and Blue Mountain Lake. Interesting climatic facts include the area experiencing hot summers and mild winters, with frequent thunderstorms during the summer months. There has been a trend towards increased precipitation in the region over the past few decades.