Read the latest on this story: Rocky View County votes unanimously to ask province to halt Springbank dam project

Rocky View County will consider Tuesday whether to ask the province to delay a major flood mitigation project upstream from Calgary — a move the city's mayor is calling "ludicrous."

In a report headed to the county's council, administrators say the Springbank dry reservoir places impacts solely on the county and the Tsuut'ina First Nation, with no benefits for the region, other options were not given adequate study and that the Tsuut'ina were not adequately consulted.

One of the options put forward is that council prepare a letter to the province, asking the project be halted and other options be considered.

'We're talking about people's lives'

Calgary Mayor Naheed Nenshi says that move would be unacceptable, as there have already been too many delays.

"To constantly be rethinking this decisions because of political expedience … is the height of irresponsibility," said Nenshi.

"We're talking about people's properties. We're talking about people's lives, and we need to get this thing built."

The dry dam — which could fill with up to 70.2 million cubic metres of water from a swollen Elbow River — is intended to protect Calgarians from an event like in 2013, when heavy rains and a melting snowpack sent floodwaters rushing into the city and nearby communities.

The ensuing disaster killed five people, saw 70,000 flee their homes and caused billions of dollars of damage.

It's faced months of delays due to landowner concerns and is currently under regulatory review by the Canadian Environmental Assessment Agency. The province said it hopes to acquire the needed space through negotiations with landowners, but if necessary will expropriate land for the project so it can be partially complete by 2021 and fully complete by the end of 2022.

87 homeowners impacted

Rocky View County Reeve Greg Boehlke says other options, like a reservoir west to McLean Creek, require further consideration.

"I believe we need to send a message that we think that things could be done differently and we want every option looked at," he said.

But in a letter to Boehlke obtained by CBC News, Nenshi says the time for reconsideration of other projects or significant changes to the plan has long passed.

"I note that two successive provincial governments have studied the options extensively and concluded that SR1 [Springbank dry reservoir] is preferable from a cost-benefit, social and environmental perspective," he said in the letter.

Boehlke said he's frustrated Rocky View County wasn't included when the initial announcement about the mitigation project was made.

"To me that's just blatantly wrong, to try to put a major league project on the municipality's land without any consultation at all."

The $432-million reservoir will require about about 3,870 acres of land. It will divert water when the river's flow reaches 160 cubic metres per second, meaning there's about a 17 per cent chance it could be used each year, Rocky View County's report states.

2013's disaster saw flows of more than 1,200 cubic metres per second.

The report found that silt from diverted floodwater could make much of the land — some of which has been owned by the same families for generations — non-viable for agriculture, and subject to invasive weeds.

"When this is used and flooded with floodwater, then the inorganic silt that comes in from the river and settles on what right now is very productive land," Boehlke said.

It would also impact 87 residential homeowners and a summer camp.

"There are no benefits to the Springbank area," the report reads.

Nenshi strongly disputes that assertion, saying the sacrifices the few dozen homeowners will have to make are well worth the payoff of protecting a city of 1.2 million residents.

"It is ludicrous to say there is nothing in it for the county. Every single family in Rocky View County relies in one way or another on the economy of Calgary for their livelihood. Many of these people in Springbank work in downtown Calgary every single day, so to take that position is absolutely anathema to thinking about this region and what makes this region work," he said.

The provincial government has stressed repeatedly that it is committed to getting the Springbank reservoir built, and has rejected McLean Creek as an alternative site. It's also committed $8.9 million to flood mitigation for Redwood Meadows on Tsuut'ina land.

Construction is set to break ground on the project in 2019.

Read Naheed Nenshi's letter to Rocky View County Reeve Greg Boehlke: