High Quality Content by WIKIPEDIA articles! Alum Creek is 58-mile (93 km) long creek that runs north to south in central Ohio. The creek originates in Morrow County and then flows through Delaware County and finally into Franklin County, where it ends at Big Walnut Creek, which drains into the Scioto River. In 1974, the Army Corps of Engineers completed the Alum Creek Reservoir near the middle portion of the creek length. This reservoir "has a surface area of 3,387 acres of water and was created to ensure a water supply for the city of Columbus, provide flood control for the area south of the reservoir, and yield recreational opportunities."