Parts of the United States are facing a shortage of sand, and officials are working on innovative ways to fix the problem. In Florida, experts say beach erosion caused by a rising sea level and severe weather is threatening the state's heavily populated coastline and valuable tourism industry.

Traditional supplies of sand used since the 1970s are running low, so local agencies are investing millions of dollars to explore alternative methods of repairing beaches and preventing erosion.  Steve Mort reports from Fort Lauderdale.

John U Lloyd State Park on Florida's Atlantic coast is typical of many beaches in the state - it is a magnet for tourists and people wanting to buy properties with a sea-view.

Beaches protect coastal cities from hurricane damage and are a haven for wildlife, including sea turtles. That is why local officials have spent nearly $24 millon to restore this beach, along with another 9 kilometers of coastline -- a process called "beach re-nourishment".

Steve Higgins, who is responsible for re-nourishing 40 kilometers of coastline, says development crowds the beachfront and flattens beneficial sand dunes.  "So there is not a lot of sand in the system. So when we do have storms and sea-level changes and so forth and we lose beach, there is no reservoir of material to restore it naturally," explains Higgins.

Rock barriers have been built to slow down erosion caused by waves, but a major port just north of the state park blocks sand from naturally replenishing the beach.

Higgins says more than 1 million cubic meters of sand was dredged from north of the port, adding between 10 and 80 meters of beach. He says he is now having to go further offshore to find sand, which costs more and could harm turtles and coral reefs.

Higgins is experimenting with alternatives to sand, such as crushed glass. "Glass is made from sand actually," notes Higgins. "So we have already run quite a few tests on the material and so far we cannot find any significant differences".

Tests are continuing to find out how animals react to the man-made material, and how it stands up to crashing waves.

Marine geologist, Charlie Finkl, says there is only enough crushed glass to re-nourish "erosional hotspots."  He explains, "These are just localized areas where there is a higher rate of erosion than the background, or the average."

Coastal engineers also use a method called "by-passing," which involves channeling or moving sand around obstacles such as ports.  As sand runs low on Higgins' section of the coast, he is not ruling out the possibility of using sand from other countries, such as the neighboring Bahamas.

A re-nourished beach can be expected to last up to 15 years.  More projects are planned for this part of Florida next year.