COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
The ice maps in this atlas were prepared to document the 1985-86 ice conditions on those reaches of the Monongahela, Allegheny, Ohio, Illinois and Kankakee Rivers that are included in study areas for the River Ice Management RIM Program, namely river mile 0 to 12 on the Monongahela River, mile 0 to 17 on the Allegheny, mile 0 to 437 on the Ohio, mile 120 to 273 on the Illinois and mile 0 to 21 on the Kankakee. The maps were prepared from interpretation of vertical aerial video imagery taken from low-flying aircraft. The interpreted ice conditions were classified into five units and transferred to base maps by reference to navigation charts and topographic maps. Ice Floes or Frazil Slushy and Pans was the most common ice unit in the lower Monongahela. Fragmented Ice Cover with Open-Water Areas was the most common ice unit in the lower Allegheny. Fragmented Ice Cover and Fragmented Ice Cover with Open-Water Areas were the most extensive ice units above Hannibal Dam on the Ohio Ice Floes or Frazil Slush and Pans were predominant below. Solid Ice Cover, Fragmented Ice Cover and Fragmented Ice Cover with Open-Water Areas were the most extensive ice types on the lake-like areas of the Illinois River, while Fragmented Ice Cover with Open- Water Areas and Ice Floes or Frazil Slush and Pans predominated elsewhere on the Illinois. Solid Ice Cover and Fragmented Ice Cover were the most common ice units on the Kankakee River.