When mayor Mufi Hannemann ran for mayor, he said there are three things we must ask about government spending:

Do we need it? Can we afford it? Can we afford to maintain it?

From our current economic perspective, the mayor’s questions are almost prophetic. With the recent City Council approval of the mayor’s request to designate 50 acres of land in Nanakuli as a regional park on the Waianae Public Infrastructure Map, the questions are also easy to answer.

No, no and no.

Make no mistake. A regional park is a wonderful idea for Waianae. It just doesn’t make sense on this piece of land.

Leeward Land LLC, a sister company of PVT Land Co. Ltd., owns the land. Adjacent to the PVT construction and demolition (C&D) landfill, the land has been held in reserve for future expansion of the PVT landfill and has been on the city’s short list of potential landfill sites for 40 years.

The City Council voted to appropriate $3 million to purchase the land, but current estimates value the Leeward parcel at about $100 million based on its highest and best use as a landfill. If the city moves to condemn the land, the issue of what the land is worth will head to court, where it will take years to resolve with taxpayers footing the bill.

At a time the city is struggling with costs — including a $1 billion-plus upgrade of sewage treatment facilities — writing a blank check for a regional park doesn’t make good sense. Especially when other land is available. In fact, when the present PVT landfill closes — which is expected in six to 10 years — it could become a park in the same way the 30-acre Honolulu Waterfront Park was created on the site of a municipal landfill. PVT proposed that alternative, but the mayor wasn’t interested.

There’s also the question of whether the city can afford to maintain a new park. Our existing parks are in chronic disrepair exactly because we can’t afford to maintain them.

But let’s put the questions of need and affordability aside.

The overarching fact is our economy depends on having an operating C&D landfill. With no place to dispose of debris, construction would grind to a halt and thousands of jobs with it. And where will debris generated by Oahu’s 20-year rail project go?

By capping Leeward’s expansion plans, the city is quashing a future source of fuel for the production of renewable energy at a time when the Hawaii Clean Energy Initiative calls for 40 percent of Hawaii’s energy to come from those sources by 2030. PVT is now awaiting approval to implement a plan to convert materials entering its landfill into feedstock for gasification that would produce energy for Oahu.

Now is the time to address our landfill capacity crisis. But wait. The city already did that. In 2003, a city blue-ribbon commission determined the Leeward property was a preferred landfill site among 45 sites evaluated. The three other sites identified for a landfill are the Ameron Quarry in Kailua, Maili Quarry in Maili, and Makaiwa Gulch, which is adjacent to the municipal landfill at Waimanalo Gulch above Ko Olina.

With so many reasons to keep the Leeward site as a landfill — and with no need for a regional park on Leeward’s land or planning documents to recommend it — why did the mayor suddenly to push the park through the City Council?

Some say taking the Leeward site out of play gives the city the argument it needs to push to expand Waimanalo Gulch. Others say influential supporters were factors.

It’s not too late to rethink the regional park. Maybe the solution is as simple as putting the park elsewhere on the west side and keeping the Leeward site as a potential C&D landfill for the good of Hawaii’s economic future.

Bill Lyon is a geologist and president of Terrpac LLC, an environmental consulting company. He has worked with landfill operators on Oahu and the neighbor islands.