The Army Corps of Engineers says the Missouri River reservoir system has recovered about a third of the storage lost during eight consecutive years of drought.

The corps said in a statement Wednesday that reservoir storage is still lower than normal, and said the commercial downstream navigation season will be shortened by 30 days. It will end Oct. 31 just north of St. Louis.

The water levels of the three biggest reservoirs - Fort Peck and lakes Sakakawea and Oahe - rose from nearly 11 feet to almost 18 feet since April 1, due to mountain snowpack and rain, the corps said.

"The near normal runoff along with the low releases for downstream flood control this spring and early summer provided significant recovery this year," Larry Murphy of the corps' water management office in Omaha, Neb., said in the statement.

The corps said runoff this year is now projected at a total f 26.3 million acre feet, up about a foot from last month's forecast. An acre-foot is the amount of water needed to cover an acre one-foot deep.

North Dakota's Lake Sakakawea rose 5.8 feet in July and 17.8 feet since April 1, ending July at elevation 1825.4 feet, the corps statement said.

Water releases from the lake averaged 13,600 cubic feet per second last month compared with the long-term average of 24,500 cfs, the corps said. The big lake is expected to remain level this month at 1825.6 feet, or 12.3 feet below normal.

The corps said the reservoir is 11 feet higher than last year at this time.

The six Missouri main stem power plants generated a record low 446 million kilowatt hours of electricity in July, only 46 percent of normal, the corps said.