GRAND RAPIDS, Mich. (AP) - The rain-swollen Grand River in West Michigan rose to above-record levels, driving hundreds of people from their homes and flooding parts of downtown Grand Rapids amid efforts to hold back the waters. The river peaked Sunday night in downtown Grand Rapids around 21.85 feet, topping the previous record of 19.64 feet set in 1985, the National Weather Service reported Monday. Flood stage is 18 feet. "We have prepared for the worst," Grand Rapids Mayor George Heartwell said. The river also crested around 17.8 feet at Comstock Park in Kent County's Plainfield Township, north of Grand Rapids, edging a record of 17.75 feet set in 1948, the weather service said. Flood stage is 12 feet. At least 100 homes in the Comstock Park area were reported to be flooded. About 1,000 people had been evacuated from downtown Grand Rapids' Plaza Towers, and the county reported that an additional 530 people outside the city were evacuated from their homes. A flooding update was expected later Monday. "My backyard is the yard and the river is behind me, now the river is to my house. I'm surrounded by water all the way around my house," resident Gary Smith told WOOD-TV. "When I step out, I have a porch and then I have one step that's still visible, and then I step down into at least three feet of water; four feet of water." In Grand Rapids, the river could stay above flood stage until later this week. More rain Tuesday could slow its retreat. "Not as much as we saw last week," Brandon Hoving, a weather service meteorologist in Grand Rapids, said Monday morning. "There is potential that some areas could get in inch." Hundreds of volunteers turned out in recent days to fill sandbags at the Grand Rapids Public Works building near downtown Grand Rapids. They've been stacked around or near buildings downtown, including the Grand Rapids Public Museum and the Amway Grand Plaza Hotel. Heartwell estimated Sunday that the city would spend at least $500,000 on flood defenses, MLive.com reported. Michigan Gov. Rick Snyder said Monday that his administration was "closely monitoring" the situation in the Grand Rapids area. "The good part is the rain seemed to stop so it didn't get the worst level it could have, but still it's serious," he said. "So we're in good communication, constant communication with people in Grand Rapids and Kent County." A 6-foot-high sand berm built around Grand Rapids' wastewater treatment plant worked to protect the facility from area floodwaters. The plant is located between the Grand River to the west and Plaster Creek to the east. The facility serves 300,000 customers in the city and 14 communities. The Fulton Street bridge over the Grand River in downtown Grand Rapids reopened Monday after being closed Sunday because of high waters. The bridge was closed because high-voltage Consumers Energy power lines attached to the bridge were deemed at risk because of floating debris, mostly trees and logs. Officials in Western Michigan urged people to stay out of the Grand River and other waterways that have overflowed their banks. The warning came after the Grand Rapids Fire Department rescued a kayaker Sunday. Flooding also has continued in central Michigan, where the Saginaw River was above flood stage at Saginaw. A flood warning was in effect for the river Monday and more rain is expected Tuesday. The U.S. Coast Guard warned people in canoes and kayaks on Monday to stay off the Saginaw River, which was flowing must faster than normal after the spring melt and days of heavy rains. Over the weekend, officials opened White Pine Middle School in Saginaw County's Saginaw Township as a shelter due to flooding in the area. Meanwhile, conditions improved in the Midland area, which had been hit by flooding of the Tittabawassee River. On the campus of Michigan State University in East Lansing, the rain-swollen Red Cedar River caused flooding of athletic fields. In the nearby city of Lansing, the course of Sunday's marathon was rerouted to avoid flooding.