Located in southwestern Iowa within the Missouri River basin, bounded on the east by the drainage areas of the Des Moines River, Nodaway River, and Tarkio Creek, and on the west by the watersheds of the Boyer River and other smaller tributaries of the Missouri River.

Extends across east-central Iowa from beyond the state line on the north to the Mississippi River on the southeast. Bounded almost entirely by the Wapsipinicon River basin on the east and by the Des Moines River and Skunk River basins on the west.

Includes the Iowa portion of the drainage area of the Nodaway, Platte, Grand, Chariton, Fabius, Wyaconda, and Fox rivers and Tarkio Creek.

Flood-elevation profiles and flood-peak discharges for floods during 1972, 1982, and 1987 in the Nishnabotna River basin are given in the report. The profiles are for the 1972 flood on the West and East Nishnabotna Rivers, the 1982 flood on Indian Creek, and the 1987 flood on the lower West Nishnabotna River. A flood history describes rainfall conditions and reported damages for floods occurring 1947, 1958, 1972, 1982, and 1987. Discharge for the 1982 flood on Indian Creek is 1.1 times larger than the 100-year recurrence interval discharge.

Includes the Iowa portion of the Upper Iowa and Wapsipinicon River drainage areas, all the drainage areas of the Yellow, Turkey, and Maquoketa rivers, and intermediate areas between these river basins which drain directly to the Mississippi River through a number of minor streams.

Includes the Iowa portion of the Little Sioux River drainage area, all of the drainage areas of the Soldier and Boyer Rivers, and a number of smaller streams which are tributaries to the Missouri River.