The inking of a deal limiting development at Turtle Bay sends two messages to the public, one seemingly at odds with the other:

» An agreement like this is exceedingly hard to reach, requiring something akin to a planetary alignment before the finalities can be nailed down.

» An agreement like this is worth all of that effort. Even the $48.5 million to be spent securing it is a reasonable price to keep a piece of the rapidly shrinking resource of Oahu’s shoreline beauty in public reach.

Honolulu officials have struggled, often unsuccessfully, to achieve balance among competing land-use values: housing, economic growth, agriculture, recreation and open space. The problem at Turtle Bay then known as Kuilima Resort started with a unilateral agreement struck almost three decades ago, handing the property owners development rights that seemingly had no expiration date.

It won a large measure of community support at the time because the former employees of sugar and pineapple plantations needed jobs. But the expansion plans for the resort were put on hold, first by global economic shifts and then by legal challenges.

Over the intervening years the job-seekers found other opportunities and, with coastal developments elsewhere, traffic problems began to mount. The environmental realities began to change, and the courts ultimately compelled the new owners of the property to update the environmental impact statement.

Clearly, the lesson learned was that the Honolulu City Council should have done a better job of projecting what would be needed for the long term. Especially in a shoreline environment confronting heightened risks from rising sea levels and other changes, land-use entitlements should never be left open-ended. The court demonstrated that an EIS can have an expiration date, even when the master agreement lacks one.

The error of the 1986 unilateral agreement was recognized by some early on, with concern rising eventually to the highest levels of government. The administration of Gov. Linda Lingle was first in 2008 to propose that the state move to limit development by an outright purchase of the 880-acre property.

A better approach was demonstrated through the process of negotiating a conservation easement. Land trusts, such as the Trust for Public Land and the North Shore Community Land Trust, have used this legal device to leave land in private hands but place a permanent restriction on its use, compensating the land owner for that limit.

It isn’t always easy to find a land owner amenable to this arrangement, but it has worked to stop a residential development in Pupukea, to preserve agriculture on former pineapple land in Central Oahu, and now at Turtle Bay.

The resort’s management firm, Replay Resorts Inc., realized that preserving areas around the pristine Kawela Bay and accepting other curbs to the original expansion plan would help enable some development to be realized amid scenic areas that enhance the marketable value of the property.

Still, there was some distance between the $40 million value set by the state’s appraisal and what the developers said it was worth unofficial reports put the resort’s appraisal at about double that amount. So it took some hard bargaining to arrive at a final figure that was at least closer to the state’s estimate.

No doubt the fact that condemnation was hanging over the deal a prospect put in place last legislative session helped to push the agreement to completion. There was significant public support for limiting development in this area, and negotiators on both ends of the table were aware of that.

The subtext there reads: It pays to play hardball on these deals, something that government and public advocates should remember for the future.

The state is right to pony up the lion’s share of the money, $40 million, because of the great public benefit. The City Council and The Trust for Public Land have a share of the credit for approving the remaining $5 million and $3.5 million of the easement cost.

For its part, Replay has more than cut in half the hotel and condominium units it aims to build. And yes, there is compensation being paid a lot of money from the public purse.

But some years in the future, when families are enjoying a rare vista from the shores of Kawela Bay, they likely will feel it was a worthy investment.

Pieces of paradise are a treasure. We need to save them when we can.