By David Madden

PHILADELPHIA (CBS) – This past winter’s beach replenishment in Cape May is going to need a little extra work. An experimental method to move the sand around produced an unexpected and unwelcomed byproduct.

Sure, the Army pumped in some offshore sand as usual. But they also tried a new process called “backpassing”- moving sand that’s built up on land too high to an area where it’s needed. Sounds logical but now some rocky deposits have appeared.

“A lot of it is pebbles and the standard small sized stone. Some, however, that if you close your hand into a fist might approximate the size,” says City manager Bruce MacLeod.

There are a few thousand tons all told over a stretch of beach from Gurney Street to Trenton Avenue. The Army’s hired a private contractor to get rid of those stones starting next week with work suspended over weekends and the Memorial Day holiday.

No one’s quite sure where the rocks came from and MacLeod won’t rule out “backpassing” again in part because it’s a cheaper way to get the job done.