FARGO, N.D. – Steve Syrdal’s house just south of Fargo is no longer near the water, it’s in it.

Swirling water runs three feet deep across his driveway, six feet deep off his back deck and around all four sides.

What’s saved him so far is the hand-built dike he constructed using plywood, sandbags and back-of-the-envelope engineering. A plywood wall draped in plastic surrounds his house, and sump pumps groan to life every few minutes, spitting out whatever water gets through.

“My basement’s dry,” Syrdal said, standing in his garage as the Red River flowed across his yard. “Unbelievable.”

For the next few days, dikes across the Red River Valley will shift and flex under the river’s pressure. Some will fail, dooming houses and neighborhoods and making for naught the labor put in by thousands of volunteers. Flood levels should remain above the 1997 levels through Tuesday, according to the National Weather Service.

Even water just three feet deep creates thousands of pounds of pressure, said John Gulliver, a civil engineering professor at the University of Minnesota. An eight-foot length of plywood board holding back that depth of water will register 6,000 pounds of pressure at the lowest point, with an average of 3,000 pounds of pressure across the board, he said.

A dike built of earth or sandbags can fail if even a small leak develops: Water forced through cracks will tunnel out a channel for more water. “It’s a catastrophic thing,” Gulliver said, adding that an earthen dam becomes much stronger if engineers use clay at its heart.

Local officials used that science to save many of Syrdal’s neighbors: They built a clay-and-earthen dike around most of the Chrisan Estates housing development where he lives. But crews built the wall on the elevated road that runs through the development, isolating Syrdal and a dozen of his neighbors who live between the road and the river.

His next-door neighbor’s house was lost Friday, along with four of the others on the river side of the dike. Syrdal almost lost his on Thursday when water bubbled up through cracks in his driveway. The bubbles soon grew into geysers as he scrambled to plug them.

Home-saving help came from a crew of volunteer carpenters from the St. Cloud area, who happened to be in the neighborhood and quickly built a second plywood dike closer to his garage, sealing off the problem.

“This is all about managing the leaks,” Syrdal said.

His dikes begin with sandbags, but he used far fewer than most people. He set half-inch plywood boards on edge, then laid a row of sandbags at their base to hold down a sheet of plastic wrapped up the wall’s face. Triangular braces of 2-by-4s stand every eight feet.

Even this doesn’t keep all of the water out. So he installed eight sump pumps to continually bail out his house. The pumps sit inside five-gallon pails sunk into the ground between his house and the dike. As water fills up each pail, the pumps turn on and push the water up through plastic pipes that angle away from his house. Every few seconds, as the pumps turn on, water shoots out of the pipes and across the river’s surface in a graceful arc.

Yet even if he survives the flood, Syrdal feels certain he won’t survive the flood of public opinion he expects to come once the waters recede. The city has considered razing riverfront houses like his to build a permanent dike. Syrdal said he understands the need and will accept it, albeit sadly.