CALGARY - Developers now have to pay up to several million dollars in security deposits before starting construction after city council approved a plan monday to deal with a string of abandoned sites.

The economic downturn has stalled work on several condo tower projects, forcing the city to issue orders demanding the holes be filled or the sites be shored up.

In some cases, the city has had to pay hundreds of thousands of dollars to fill a hole because of safety concerns, such as sinkholes.

The security deposits are meant to cover the cost of backfilling a hole and, along with an increased indemnity to cover the cost of any roads damaged during construction, are meant to ensure the city isn't stuck with the bill for stabilizing a site.