|Storm Total Rainfall:||4.26"|
The greatest known flood in Youngstown occurred on the lower Mahoning River on Wednesday, March 26, 1913. The Mahoning River reached a crest of 26.5 feet on Wednesday Night around 11 p.m., 16.5 feet above the current flood stage and seven feet higher than the previous record set in 1904. A severe blow was dealt to the area. The estimated peak discharge of the Mahoning River during the 1913 flood was 44,400 cubic feet per second (cfs) at Youngstown. The largest flood of recent years, as recorded on the Mahoning River at Lowellville Gage, occurred on January 21, 1959, and had a discharge of 21,000 cfs. Other significant floods of record occurred in March 1910, March 1936, and January 1937.
The city of Youngstown lies in hilly terrain, mostly immune to flooding. The railway and manufacturing areas were in the heart of the flood zone. The city’s water plants were flooded, cutting off clean water to the citizens for days. Many industries suffered extensive damage, major bridges were washed away, and electric power and water services were out.
Runoff from the upper Mahoning River Basin is modified by three major flood control dams operated by the U.S. Army Corps of Engineers (USACE). The Berlin dam on the Mahoning River in western Mahoning County, placed in operation in 1943, controls the runoff from 249 square miles. Lake Milton, located just downstream from Berlin Dam and constructed for water supply in 1916 by the City of Youngstown, is operated in conjunction with the Berlin Reservoir. The Michael J. Kirwan Dam, completed in 1966, is located on the West Branch of the Mahoning River in Portage County. It controls the runoff from a drainage area of 80.5 square miles. The Mosquito Creek Dam on Mosquito Creek in Trumbull County was completed in 1943. It controls the runoff from the drainage area of 97 square miles.
In addition to the dams operated by the USACE, Milton Dam, which was built in 1917 and is owned by the City of Youngstown, is operated in conjunction with Berlin Dam to form a single operating unit. This network of dams reduces major floods on the Mahoning River at Youngstown by an average of three to six feet.
Also, the USACE Pittsburgh District completed in May 1973 a local flood protection project on Crab Creek. The project, which covers about 2.3 miles of the stream, is basically a channel improvement project of concrete and stone lining. It is designed to contain within the banks, a flood equal to the January 1959 flood, a 43-year frequency flood, and will reduce major floods by an average of six feet.