Scuba divers and snorkelers: Get ready for some cloudy ocean waters between Key Biscayne and Miami Beach over the next month or so. The U.S. Army Corps of Engineers is set to begin a $15.8 million beach renourishment project on Miami Beach.

The first phase, starting the last week of February, calls for dredging about 250,000 cubic yards of sand from a borrow pit off Key Biscayne and pumping it through a buried pipeline to the beach between 63rd and 69th streets, where it will be spread.

That phase is expected to be completed by April.

Part two of the beach restoration begins in May and won’t involve any offshore dredging. Instead, about 107,000 cubic yards of sand already on the beach between 10th and 18th streets will be spread onto an eroded section between 27th and 44th streets. That project is expected to wrap up in November.

Federal and county officials say the aim is to protect the shoreline from big storms.

The dredging phase is expected to cloud local waters as sand being sucked up by the dredge from a pit about four miles off Key Biscayne flows north in the water column to Miami Beach. A similar renourishment project about a decade ago that involved dredging just under a million cubic yards from the same pit to Sunny Isles Beach proved a major headache to scuba divers. Some complained of floating curtains of sand that reduced visibility and coated local reefs and sea grass beds with sediment.

Brian Flynn, Miami-Dade’s veteran beach renourishment chief, says this month’s dredging involves a lot less sand over a shorter time period and — like the Sunny Isles Beach project — should have no lasting ill effects.

“There is going to be some silt on the reef, but reefs are adapted to that,” Flynn said. “When we have major storms, silt gets on the reef. Essentially, three weeks after construction was completed [in Sunny Isles Beach], the reef was back to the way it was. There was no long-term impact. We can say pretty confidently that, unless there’s a massive screw-up, these projects can be done without any major impacts.”

Flynn noted that officials with the county’s environmental agency will monitor the work to make sure the contractor, Great Lakes Dock & Dredge, maintains a 400-foot buffer between dredging equipment and the reef. Divers will look out for any possible damage to coral or sea grass and check for excessive sediment.

U.S. Army Corps of Engineers project manager Jason Harrah agreed: “We have extremely stringent environmental standards. I’m not saying something wouldn’t happen. But if it did, it would be taken care of immediately.”

Like it or not, Flynn said, beach renourishment projects are here to stay. He cited economic studies showing that for every dollar spent on restoring the beach, communities receive $10 in economic benefits.