Declining enrollment and escalating costs mean that Aquidneck Island’s three school districts cannot afford to remain independent and maintain the same quality of education, according to a study by the Rhode Island Public Expenditure Council.

Unless Newport, Middletown, and Portsmouth pool resources and services and consolidate spending to realize economies of scale, the RIPEC study concluded, the districts will become mired in deficit spending over the next several years while seeing the scope of their academic programs curtailed.

In short, they will be spending more to get less, John Simmons, executive director of the business-backed organization, told an advisory panel on regionalization. The findings are being made public at a time when school districts throughout Rhode Island are confronting severe taxpayer resistance to providing them more money. The report, Simmons said, can serve as a model for other Rhode Island communities that want to explore varying degrees of consolidation.

RIPEC’s 150-page analysis offers six options for the island’s three districts, from maintaining the status quo to a complete merger. Although not recommending which option the districts should pursue, RIPEC found that making no change could lead to sizable financial problems, and merging services could result in estimated annual savings of $2.8 million to $12.3 million, depending on the degree of consolidation. The savings would begin to be realized in 2012.

The most far-reaching model assumes one central school administration for all the schools on the island. It anticipates the closing of one high school and one middle school but doesn’t designate which ones. Working with the lone superintendent would be two assistant superintendents and one director each for finance, facilities, student services, technology, athletics and academics.

Simmons said that the decline in students that is already under way makes it uneconomical for the individual districts to continue to offer the same range of academic programs unless they merge.

In the last four years, Newport, with a current enrollment of 2,096, has lost nearly 20 percent of its students and is expected to lose 21 percent more by 2014.

Portsmouth, currently the largest district, with 2,908 students, has lost 5 percent of its enrollment since 2005 and is expected to see an additional 8 percent decline by 2014.

Middletown’s enrollment stands at 2,378, or 7.3 percent less than in 2005. A further reduction of 8.6 percent is anticipated for 2014.

If the school districts do nothing to consolidate expenses, the study predicts, they will start to see deficits in the coming fiscal year, 2010.

According to RIPEC’s projections:

•Newport would finish 2010 about $500,000 in the red. By 2014 the annual deficit would climb to $3.6 million.

•Middletown would come up $300,000 short in fiscal 2010, with the yearly gap increasing to $2.8 million in 2014.

•Portsmouth would experience a $200,000 deficit in the coming year and also fall farther behind each succeeding year until the shortfall stands at $2.2 million in fiscal 2014.

Simmons presented the report to the Aquidneck Island Advisory Group, chaired by Charles Shoemaker, chairman of the Newport School Committee, on Friday.

The panel of elected and appointed school and municipal officials, as well as the executive director of the Aquidneck Island Planning Commission, has been authorized by the three municipal governments on the island to explore the feasibility of regionalization.

Simmons recommended that the communities begin to explore in greater detail the feasibility of regionalization in three categories:

•The merger of services such as information technology and school payroll.

•Joint planning for classroom instruction and a combined study of all school facilites to determine if additional savings can be realized by reorganization.

•A legal analysis of the way a unified school district would be governed and the way secondary education would be delivered, with the option of retaining existing buildings or building one large high school and one middle school.

“You can negotiate how to consolidate, so that there is a comfort level in each community,” Simmons said.

Portsmouth Schools Supt. Susan F. Lusi said that consolidation would enable communities to stay within state-mandated ceilings on property tax increases “and keep a school system as good or of better quality without running a deficit.”

“But it gets trickier when you try to figure out who pays for what,” she said.

The plan suggests that per-pupil expenditures for Portsmouth students would increase by a couple of thousand dollars per student in a consolidated school district, but Simmons warned that does not mean the tax rate in Portsmouth would rise by a commensurate amount.

The advisory panel has not decided whether to formally accept the RIPEC report, but comments at Friday’s meeting ran in favor of regionalization.

Tina Dolen, executive director of the Aquidneck Island Planning Commission, said the group should invest time in explaining the details of the 150-page report to community groups.

Shoemaker said the group also needs a separate, outside evaluation of the educational quality on the island.

And there must be consensus in the three communities about moving forward or “it doesn’t go,” he said.

“Too many of us have had these 4-to-3 votes,” Shoemaker said.

Newport Schools Supt. John H. Ambrogi said he has always favored consolidation, but “this is a political decision.”

“We will have to sign on all the residents of the three communities,” Ambrogi said.

“Operationally, we can do it,” he said, but he questioned “whether there is the political will to do it.

“I’m skeptical as to whether it will come to fruition,” he said.

gmacris@projo.com