Irvine Co. Adds 4-Acre Lot to Deal With Conservancy : Land: Newport Beach environmental group’s acquisition depends on property owners voting to tax themselves a maximum of $120 a year for 30 years.

The open space agreement between the county’s largest developer and a local environmental group got a bit sweeter Monday, as officials announced that a four-acre bay-front lot known as Lower Castaways will be included in the land voters can buy through special assessments on property owners.

According to an agreement hammered out in recent weeks by the two sides, the Irvine Co. agreed to include the Lower Castaways in the sale of an additional 134 acres that the company had already agreed to sell to the Newport Conservancy.

For the lot, which is at the corner of West Coast Highway and Dover Drive, the company is asking an additional $2.5 million, or its appraised value, whichever is lower. That would increase the total cost of the deal for the three properties that make up the package to $58.3 million.

Last month, the company and the conservancy announced that they had reached an agreement on the purchase of two other properties known as the Upper Castaways and Newporter North bluffs overlooking Upper Newport Bay.

The Newport Conservancy also proposed that the Lower Castaways become the site of the Newport Harbor Nautical Museum and an adjacent parking lot, said Robert Shelton, the former Newport Beach city manager who is directing the conservancy’s campaign to purchase these lands.

“This is a site that is beyond my wildest dreams,” said Art Gronsky of the Nautical Museum, which is now located in a small city-owned building on Balboa Peninsula.

The additional land is historically significant, since it was the site of the original McFadden’s Wharf, where steamships first landed in Newport in the 1880s, Gronsky added. “If we pray hard enough, we might get it.”

For that to happen, Newport Beach property owners would have to vote to tax themselves a maximum of $120 per year for 30 years to finance the public land acquisition.

If the measure failed in November, the entire deal will be canceled and the Irvine Co. could proceed with development plans to build 360 homes, and a 71-space marina, on the lands.

The share of the $120 annual assessment attributable to the Lower Castaways amounts to about $6. Shelton said the conservancy will “find a way to structure” the entire purchase so that the additional land will not force residents to pay more than a $120 annually.

Before the City Council puts the needed special assessment district to a vote on the November ballot, some council members have suggested that they will have to decide if a simple majority vote is a strong enough mandate to proceed with such a large purchase.

Castaways Deal Voters to decide whether to buy land.