OSAWATOMIE, Kan. (AP) - Even after sunshine returned to southeast Kansas and southwest Missouri, rivers swollen by days of heavy rain inched dangerously upward across the Plains.

The Kansas National Guard was sent to help with a mandatory evacuation of Osawatomie, a small town in eastern Kansas and one of the hardest-hit communities in the region.

The levees and dikes held, after reinforcement work by volunteers with sandbags, but rainwater pooling in low-lying areas overwhelmed pumps and flooded neighborhoods.

Kansas Governor Kathleen Sebelius on Sunday added six more counties to her declaration of a state of emergency and said she planned to survey the damage Monday.

In Osawatomie, which evacuated 40 percent of its residents when areas near two rivers flooded, Mayor Philip Dudley kept an eye on Pottawatomie Creek on the town's south flank and the Marais des Cygnes on the north.

“It's going to be a few days before we get some of the higher rivers to come down, said Maren Stoflet, a National Weather Service meteorologist in Pleasant Hill, Mo.

In Independence and Coffeyville, officials were preparing for additional flooding along the Verdigris River, which already has set record levels, as the U.S. Army Corps of Engineers planned to open floodgates at the Elk City and Fall River Toronto Lake reservoirs farther upstream to alleviate pressure.

The Verdigris River at Independence set a new record of 52.4 feet Sunday morning, shattering the old mark of 47.6 feet and more than 20 feet above flood stage. In Coffeyville, the old record of 26.6 feet fell Saturday night as the river surged past 29 feet, more than 10 feet above flood stage.

“Releasing the water may not cause the river to crest higher, but it may cause the crest to remain for a longer period of time, said Robb Lawson, a National Weather Service meteorologist in Wichita.