Mexican President Andrés Manuel López Obrador on Monday symbolically launched work on a new airport for Mexico City to replace the nearly half-built $13 billion project he cancelled upon taking office.

López Obrador promised the new Felipe Ángeles airport northeast of the capital won't exceed its budget and will save the government money even with the cancellation of the partially built airport.

"It's going to resolve the problem of saturation at the current Mexico City airport , but also be an example of how you can carry out a rational, austere policy based on honesty that needs to establish itself as the way to live and the way to govern in our country," López Obrador said.

The new airport — named for a general allied with revolutionary icon Pancho Villa — is at the Santa Lucia military air base and the army is in charge of getting it built for $4.1 billion.

It is supposed to begin operating in mid-2021, though construction has not yet begun.

Two new runways would be added to its existing one and the commercial airport would share the space with the military.

Critics have argued that the new airport will have difficulty operating simultaneously with the existing airport, but in a report by the military, consultant Navblue said they could operate simultaneously in terms of air space.

One of the early hitches pointed out in the military's environmental impact statement is a small mountain named "Paula" that sits beside one of the runways. It would be too close for commercial airliners to use that runway, so the report says it would be dedicated exclusively to military use.

But the biggest concern raised in the report has to do with water. The airport would consume an estimated 6 million liters (1.6 million gallons) per day from an already severely overtaxed aquifer that the capital depends on, and that's not including consumption from hotels and other businesses that will spring up around it, the report said.

Three existing wells on the air base should provide enough water, but that is expected to lower the water table in the aquifer, so some wells could go dry.

The report says that could be mitigated by creating recharge zones in the area to put water back into the aquifer. Another possibility would be bringing water from another, less-stressed aquifer.

On Monday, the Zeferino Ladrillero Human Rights Center called on the government to consult with the more than 20 communities around the airport. The group warned that the water consumption would directly impact livestock and agriculture, and with it the livelihoods of thousands of families.

López Obrador, though, said consultations had already taken place.

"I can tell you now that the consultation with the communities around Santa Lucia happened and what do you think? The people approved the project," he said. There was no description of when or how those consultations were performed.

When the time the airport it begins to operate in mid-2021, it could handle nearly 20 million passengers.

One of the looming questions is how flights will be divided between the capital's main airport, Benito Juárez International, and the new one at Santa Lucia. The environmental impact statement for the project mentions that initially two airlines will be operating there, but it does not say which.

The new airport would connect to the existing one via a 28-mile (46 kilometer) route with dedicated bus lanes to speed passengers to their connecting flights. About 5 miles of that route would actually be along a perimeter road built for the now-cancelled airport at Texcoco.

In October, before López Obrador had taken office, he held an unofficial referendum on cancelling the $13 billion Texcoco project, which was already nearly half completed. He proposed converting the Santa Lucia air base and making improvements at Benito Juarez, which had been targeted for closure. The plan received 70% approval, though critics complained that fewer than 2 percent of Mexico's registered voters took part.

López Obrador complained the Texcoco project backed by the previous administration was drenched in corruption and faced environmental problems because it was being built on a former lakebed. Auditors said in February that they had found some $167 million in questionable costs.

The government says it will build a third terminal at Benito Juarez. That airport, surrounded by residential neighborhoods and with no possibility of adding an additional runway, is beyond capacity. More and more flights are parked on the tarmac with passengers shuttled to the overcrowded terminals on buses.

Arriving flights are increasingly delayed because they can't get a landing slot.

The government announced last week that the nearly 31,000-acre (12,500 hectare site of the scrapped airport would be converted into a park.

The survival of Santa Lucia, which also had been set for closure under the Texcoco plan, is another victory for Mexico's military, which has been tasked with running the project. It also has been given the lead in combatting the country's rampant fuel theft problem and a soon-to-retire general will head the newly created militarized police force, the National Guard.

The general in charge of airport construction said Friday that its design would be "austere," in contrast with the elaborate Norman Foster-designed terminal for the now cancelled airport. The government says even factoring in the lost investment in the cancelled airport and the cost of converting Santa Lucia, the total expense will be only slightly more than a quarter of what the Texcoco airport would have cost.