Engineers cracked open spillways Saturday at Bull Shoals Lake, allowing excess water brimming near the rim of the dam to rush down the White River to communities already flooded by weeks of rain.

Meanwhile, two people drowned Friday in Yell County when their pickup truck left water-covered Arkansas 28 and sank over the top of its cab in floodwaters next to the highway, the sheriff's office said.

Both forecasters and officials with the U.S. Army Corps of Engineers said the new water wouldn't push river levels much higher than already seen through Arkansas' Delta region. However, any new rains washing into the reservoirs making up White River basin would put even more pressure on lakes that likely won't drop for months.

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"They are essentially mimicking normal operations," said Steve Bays, a hydrologist with the National Weather Service in North Little Rock. "We factored that into our forecast (Saturday) morning for Calico Rock and we still see a falling river."

The White River crested at Calico Rock — just downstream from Bull Shoals Lake — at 40.23 feet Friday. By Saturday afternoon, river monitors showed a more than 20-foot drop. Forecasters said a 34-foot crest should hit Augusta and Newport down river Sunday. The levels will only be just slightly above what hit the communities during March flooding, Bays said.

The weather service predicted a 34.2-foot crest to hit Des Arc by Thursday, while flood levels should remain about 32 feet near Clarendon.

More than three-fourths of Arkansas' counties have been declared disaster areas by Gov. Mike Beebe since tornadoes tore across the state Feb. 5. The White River, which cut off the community of Georgetown and flooded many homes, has dropped slightly over time since. However, high reservoir levels forced the corps to open spillways.

Engineers earlier began letting water out from Beaver, Table Rock and Norfork lakes, which dump water into the White River. The river rises in northwest Arkansas, then heads north to Missouri before turning south to dump into the Mississippi River. Corps spokesman P.J. Spaul said the Bull Shoals release, slated to run through Tuesday, would be far less than the water let out from other lakes.

"This is not going to be a really large release like what was going on at Norfork Lake," Spaul said. "It's going to be less than they anticipated originally."

But the long-term flooding continued to rush against levees soaked for weeks by the waters. The Black River, a tributary of the White River, broke through a levee Saturday near Poplar Bluff, Mo., forcing the evacuations of about 50 homes as officials said waters rose as high as three feet in some spots.

Spaul said a Corps employee who looked at the levee Friday found it "pretty saturated."

"That riverbank there has been having some places where they're having slides on it," Spaul said. "We'll have to wait until the water equalizes. It's pretty hard to do anything when you've got water flowing through a levee."

In Yell County, a news release from the office of Sheriff Bill Gilkey said Julio Cano, 59, and Magdalena Dominguez, 55, both of Dardanelle, were westbound on Arkansas 28 when their truck drove off the highway early Friday evening. Gilkey said the portion of highway their truck was traveling on, west of Plainview, had been barricaded to keep traffic from passing over a section covered with about 2 1/2 feet of water.

"A witness who was in the area looking at the height of the water caught a glimpse of the truck just before it became submerged in the water, and alerted the Yell County 911 Center," the sheriff said.

The bodies were recovered from the water later in the evening.