PHILADELPHIA — Emerging from Irene, the hurricane that weakened to a tropical storm, Pennsylvania residents and emergency officials are keeping a close watch on swollen rivers that threaten to spill over their banks and cause more damage by flooding than the wind did.

Across the eastern half of the state, swollen creeks and rising rivers jostled and streamed, already filled to capacity by an abundantly wet August and expected to overflow from the rain Irene let loose overnight Sunday in New York and New England.

Along the Delaware River, communities readied for the water, with Easton and New Hope braced for major flooding that the National Weather Service said could come this morning or afternoon if the river crests to 31 feet, or nine feet above flood stage.

Easton Mayor Sal Panto Jr. said it’s more than likely the waterfront of the city of nearly 27,000 could be inundated, but as to how far the water might stretch, it’s anybody’s guess.

The city has flooded before — five times since 1996 the river has crested over 30 feet, a newspaper reported — but the city is ready. No mandatory evacuations have been issued but residents who live in low-lying communities know that it’s part of living there.

“We’ve had higher. We’ve had 37 feet,” Panto said. Optimistically he predicted that flooding would be moderate.

On Sunday, it was another river, the Schuylkill, that wreaked havoc, cresting to more than 15 feet in Norristown and inundating homes with muddy water and flooding streets in Philadelphia, too.

In Philadelphia, the Schuylkill flooded low-lying streets and crested at 13.56 feet just after 2 p.m. — below the 15-foot level that city officials had forecast but still well over flood stage — and fell back to 13.42 feet. It began dropping as night fell.

Irene has contributed to at least four deaths in Pennsylvania and left hundreds of thousands of residents without electricity.

Gov. Tom Corbett cautioned that residents across the state needed to be mindful of the risk of flooding.