The Missouri River along Iowa’s western border is so low, it’s affecting commercial transportation. Several consecutive years of drought have the river’s flow so diminished, barges have trouble getting as far north as Omaha. Army Corps of Engineers spokesman Paul Johston says they’re doing what they can, releasing water from upriver dams in the Dakotas to raise water levels. Relatively steady releases to help out the birds, but navigation levels are minimal and no doubt will stay that way. The corps is pledged to manage the Missouri River to meet the needs of cities, power plants, shippers and recreational users along its length, a mix that can be contradictory and difficult to fulfill.They’re setting it up to keep water flow in the river around 26-thousand cubic feet per second during nesting season, and as tributaries dry up, release will be increased to keep water at certain mimimums that will allow some navigation. Johnston says a sand and gravel dredge will clear away shoals from the river up to its confluence with the Osage in Missouri, helping barges make the passage that far north. The barges carry grain down the river from ports in Sioux City in the fall, and this time of year they bring fertilizer for farmers along the Nebraska and Missouri banks of the river. Recent years have seen lawsuits against the Corps, by business interests that want more water released from the big hydro-electric generating dams, and upriver states that say lowering reservoirs behind the dams will cost them tens of millions in revenue from boating and fishing.