Adams County has four levee/drainage districts in the Mississippi River:

• The Lima Lake Drainage District is located in the northern part of Adams County and protects 14,256 Acres of farmland.

• Indian Grave Drainage District is directly south of Lima Lake and protects 19,634 acres.

• The South Quincy Levee District, containing 5,515 acres, is located just south of Quincy. This relatively small levee district is a major industrial area, with some agricultural and residential properties.

• The Sny Island Drainage District, located in southern Adams County, protects 110,000 acres in Adams and Pike Counties, with 11,792 of those acres in Adams County.

Due to the fact the entire length of the county lies along the Mississippi River, the county has a wide expanse of floodplains. There are approximately 100 square miles of floodplain in the river bottoms and an additional 20 square miles of floodplains along the small creeks and tributaries, giving Adams County 120 square miles of floodplain.