PHIPPSBURG — During summers spent as children at their cottage at Popham’s Hunnewell Beach, Fred and Richard Hill’s mother, Harriet, always told them the erosion that scours the sand followed a 50-year cycle.

Some years, the ocean makes its way up the sand to the cottages and then — sometimes leaving destruction in its wake — cedes the land back.

Over the years, efforts to hold back the waves have intensified, most notably during the 1970s when 11 cottages fell into the sea.

This year, as powerful storms carved into the dunes at Popham Beach State Park, some homeowners reinforced a stone seawall.

But on Friday, as temperatures neared the low 60s, Fred Hill and his wife, Marty, stepped onto the deck of their family’s home and surveyed the damage since last year. Raised in 1978 onto telephone poles, their cottage has survived the brunt of the storms, although other methods, such as a seawall made of 35 used cars, were not as successful.

Fred and Richard Hill agree that eventually there may be nothing they can do to hold back the sea.

Erosion, the brothers said Friday, has always been a natural phenomenon on the 3,650-yard, crescent-shaped beach.

News clips from the 1960s quote homeowners worried about protecting their cottages from the “Popham Erosion Problem.”

Homeowners differed about how to address the erosion. In 1966, the owner of a small store set used cars in front of his property hoping to block the waves, also setting in motion a protracted legal battle among homeowners along the beach.

But later that year, winter storms washed the cars away, and a house and restaurant were eventually lost to the sea.

“That’s the year [1966] the trees started to disappear from the beach,” Fred Hill said.

The Hills believe that such interventions only exacerbated the trouble — and sent pieces of metal down the pristine beach.

Geologists told reporters that much of the erosion was “man-made,” and that a stone sea wall built at the site of the old store would not prevent erosion and might in fact worsen it because it would redirect the energy of the waves.

“These people may have a problem for which there may not be a solution,” geologist Barry Timson is quoted in the Press Herald in March of that year. Measures such as the sea wall, he said, “will give the beach property owners some period of grace, during which they can decide whether to just pull out or try to sell their problems to someone else,” the Press Herald reported in April 1975.

In 1976, a 15-foot-high, 400-foot sea wall of boulders was built a few properties from the Hills. That summer, 11 cottages fell into the sea, including “three to our east, one to our west.”

At first, the Hills tried to withstand the waves with sandbags and “bulldozing at every tide,” Richard said.

But in 1977, they raised their cottage — at that time a single-story ranch — onto telephone poles in an attempt to outwit the sea.

And they set up posts and ropes to keep beachwalkers off the grass and from breaking the roots, Richard said.

Then the tide turned, and the erosion calmed. By 1985, the grass had begun to return, and a 1998 photograph shows “a “football field” of seagrass between the house and the sand,

Whatever the pattern, Fred and Marty Hill, who live year-round in Arrowsic, walked the beach in front of their family’s cottage on Friday, leaving their jackets on a large piece of driftwood on the “lawn” of seagrass that Marty Hill said has been reduced by half by the strong waves since last year.

But just down the beach, two other property owners are taking a different approach. Excavators are lifting large boulders onto an existing seawall — a wall Richard Hill blames for exacerbating the erosion, and for contributing to a new sandbar that runs diagonally from Fox Island to the front of the Hills’ home.

The sea wall, he said, “has totally, totally, disrupted the cycle of the beach,” which he now guesses is on a 12- to 15-year cycle.

“It’s looking to me as if the erosional pattern is stronger than the build-up pattern,” he said.

The Hills say some of the efforts at quelling the erosion — such as the sea wall — have only exacerbated the problem. Fred Hill suggests the erosion cycle is not 20 to 25 years, while Richard surmises it is as short as 12 to 15 years — and getting shorter.

More recently, the issue has drawn scrutiny from local and state officials, who have worried that Route 209 — the only road to Popham Beach State Park and Fort Popham — could be in jeopardy should the erosion continue.

Phippsburg Police Chief John Skroski said that, with no dunes to protect it, the ocean creeps closer to Route 209 each day.

So on Thursday, Skroski and other town officials met at Popham with officials from the Maine Department of Transportation to show them the recent damage and asked what could be done.

“Currently we’re not in imminent danger of losing the roadway,” Tim Cusick, superintendent of operations for the DOT, said Thursday. Any action — such as a rock retaining wall — would require involvement by the Army Corps of Engineers and Department of Environmental Protection, Cusick said.

Selectman Curtis Doughty, who grew up in Phippsburg, said that since the last storm, the beach has crept about 50 feet closer to the road.

“This was an island years ago, they tell me,” he said. “I don’t know what’s going to happen.”

But the Hills suspect they know, because their mother, Harriet told them.

And Fred Hill said that, knowing the likely outcome, “we’ve been careful not to undertake any major expenses.

“This is just the natural process, she always used to say.”