Kailua resident David Brezel, 89, has been swimming daily at Kailua Beach for the past seven years.

Until recently, he entered the water near the boat ramp near the entrance to Lanikai.

Now, exposed cinder blocks stick out where sand used to be, forcing a detour in his routine. He now starts his twice-daily swim on the Kaneohe side of Kaelepulu Stream.

“;The waves are smashing onto (the blocks), and it's dangerous, and I can't go swim there anymore,”; said Brezel, a retired eye doctor. “;I like to swim there.”;

It's just one sign of erosion that's eating away Kailua Beach, which in 1998 was ranked as America's best beach.

Now, erosion has created a drop of about 6 feet before patrons can reach the sandy beach. Roots and pipes extend out of the sandy wall into midair.

The city recently removed 10 ironwood trees because they were being undermined by erosion, said city spokesman Bill Brennan. More trees might also be removed.

Some trees had fallen over because of the loss of beach, said Will Ho, the Windward District manager for the city's parks.

Charles “;Chip”; Fletcher, a professor in the Geology and Geophysics department at the University of Hawaii at Manoa, said erosion at Kailua has made it difficult to walk across the beach during high tide.

“;It's a beach park, for god sakes,”; he said. “;It's severe. It's been unrelenting for the last two years. It's approaching three years now.”;

The exposed cinder blocks, he said, are “;sandgrabbers”; built about three decades ago. They were meant to hold sand on the beach.

Now crumbling, the blocks are held together by corroded iron rebar.

Fletcher, a coastal erosion expert, said Kailua Beach had been growing for decades, but the southern portion started to erode the past 10 to 20 years. The erosion near the boat ramp has accelerated in the past two to three years and is now washing away the beach at a rate of 1 to 3 feet a year, he said.

The cause remains elusive.

There are a number of factors from a change in wind patterns to high surf that can lead to erosion, he said.

Fletcher thinks one culprit could be sand going into the mouth of Kaelepulu Stream.

The city regularly dredges the stream, but cannot use sand from the canal to replenish the beach because of federal clean-water requirements.

At the same time, the city dredges only a narrow portion of the stream, Fletcher said. While a heavy runoff could push the sand in Kaelepulu Stream back into the ocean, a dike upstream diverts some of the water to another canal in Kailua, Fletcher said.

The dike was built in the 1980s after flooding damaged the Coconut Grove neighborhood in Kailua.

The state Department of Health is seeking permission to allow the city to use sand recovered from the stream mouth for replenishing the beach.

“;The redepositing of the dredged sand from the stream, it can be done, but there are permits, certifications and clearances needed from different agencies,”; said Joanna Seto, engineering section supervisor of the Health Department's clean-water branch.

Dolan Eversole, a state coastal geologist, said erosion has been increasing around the state, not just at Kailua Beach.

“;In the last five years, there seems to be a sudden shift to erosion. Many of the beaches that were formerly stable like Kailua are now beginning to erode,”; he said.

Factors in the erosion could be locking up of sand by human activity, such as building structures, or the rising sea level, he said.

The state has recently hired a consultant for $45,000 to create a Kailua Beach management plan to provide options for dealing with erosion that has been damaging the beach, said Eversole, who is on loan to the state land department from the University of Hawaii Sea Grant program.

A company called Plan Pacific will create recommendations for management strategies by 2010. The plan will look at erosion, beach management and land use.

“;We're hoping that this will be the first of many more strategic beach management plans for the state,”; Eversole said.

There will be public meetings and workshops with the consultant to solicit concerns from the public .

Meanwhile, state officials still don't know why Kailua Beach's sand is slipping away.

It's unlikely that restoring the sand from the stream mouth will solve the erosion problem, but it could help, Eversole said. “;It's the first thing to try.”;