In the wake of the largest flood in Alberta history, the Tory government announced a sweeping plan to move homes and businesses out of the areas most in danger from a deluge and to flood-proof other areas at risk from rising waters.

But many of the details of the province’s initiative have yet to be nailed down, and the impact on communities such as Calgary and High River is still uncertain.

In a rare Sunday news conference, Municipal Affairs Minister Doug Griffiths announced the province will ban new development in floodways — the areas subject to the most destructive flows in so-called “100-year floods.”

The province will allow — and pay for — the repair and rebuilding of damaged homes in floodways, but it will not pay for damages from future floods on refurbished homes in those zones, he said. If a property owner chooses to relocate, the province will provide financial assistance for a new home.

Premier Alison Redford said in an interview that the government is trying to provide “the most choice with the least impact,” but acknowledged the policy will mean tough choices for some homeowners.

“There are people who have homes on the floodway that they love and we’re saying, ‘really, if you want to choose to stay there, you have to understand there are consequences.’ That’s going to be hard for people to hear, but I also think that most people are going to realize that makes sense,” she said.

In flood fringe zones — the portion of hazard areas outside of the floodway — the government will pay for repairing or rebuilding homes affected by the recent disaster, but will require flood-proofing such as berms, water control infrastructure or raising the structure.

The government will pay an additional 15 per cent over replacement costs for flood-proofing measures on individual homes in some cases. In other instances, broader municipal flood mitigation efforts will suffice, but that will only be determined through consultation with municipalities, Griffiths said.

If no flood-proofing takes place, homeowners will not be eligible for disaster assistance in the case of a future inundation. Homeowners in floodways and flood fringe areas across the province who weren’t affected by the recent flooding in southern Alberta and Fort McMurray won’t be relocated and will still be eligible for assistance in case of future flooding.

Griffiths acknowledged the province has no estimate of the number of houses affected by the new policy — though he says the amount located on floodways is small — or the cost involved. The Progressive Conservative government announced an initial $1-billion for flood relief and reconstruction, but said more money would certainly be needed for a disaster estimated as causing multiple billions of dollars in damage.

Mayor Naheed Nenshi said he knows the government had to move quickly but he was surprised that such a major policy shift would take place without consultation with municipalities.

While he doesn’t disagree with the government’s intent, Nenshi is concerned about how the government will determine what properties fall within each category, saying there are differences in expert opinion over what areas should be considered floodways and what should be designated flood fringe areas.