The Mahoning River and its watershed played a significant role in the development of Youngstown. Before the mid-1700s, little is known about the Mahoning Valley, but it was a lush, fertile flood plain used by Native Americans traveling from the Ohio River north to settlements in the areas now known as Cleveland and Detroit. The name Mahoning likely comes from the Delaware word Mahoni, meaning a salt lick, or Mahonink, meaning at the salt lick, reflecting the area's natural springs and the importance of salt to Native Americans and early settlers. In 1796, John Young and his surveying team traveled the Mahoning River and stopped at the banks of Spring Common during an expedition that eventually led to the founding of Youngstown. The river first served as a source of drinking water and transportation, then became central to the local iron and steel industry by supplying water to cool hot metal and by receiving waste water from mills along its banks. With no environmental controls until the late 20th century, decades of industrial pollution severely damaged the river; in 1952, a U.S. Geological Survey study called it among the worst polluted streams in the United States. During the industry's peak, more than 400,000 pounds of contaminants were discharged into the river each day, and water temperatures sometimes reached 120 degrees Fahrenheit. In 1913, a record flood inundated Youngstown, submerging major parts of downtown and industrial sites along the river and demonstrating the need for improved stormwater management, bridge and water supply design, and floodplain planning throughout Ohio. After the Clean Air and Water Acts and the decline of the local steel industry in the late 1970s, water quality and aquatic life gradually began to improve. Spanning 113 river miles, the Mahoning River long served as the region's lifeblood, and efforts are now underway to clean it, expand recreation, and support new community and economic development along the riverfront.