The chances that Prince William County will move its proposed $20 million courthouse complex out of the present site in Manassas have been sharply reduced by a consultant's finding that the shift would generate little new growth.

The county Supervisors have been considering 12 locations, including the present one in Manassas, which became an independent city two years ago, and had planned to make a decision in August.

A county bond referendum of $16.5 million for the courthouse complex and $4 million for a jail were expected to be placed on the Novemeber ballot.

A decision by the Supervisors to move out of Manassas also would have had to go to the voters.

There has been strong sentiment on the Board against pouring money into a site that was no longer part of the county and a hope that the move could be justified economically be the growth it would generate.

A report presented recently by consultants O'Malley & Associates, Inc., found however, that "even in the event of a several-thousand-acre new town, industrial development would proceed slowly because of the lack of access to supplier and consumer markets and the greater distance from the central Washington area."

Scott D. MacDonald, who drafted the economic development study, warned the Supervisors, "Don't make the courthouse decision on an industrial or office development basis."

MacDonald said that industrial development in the entire Washington area has been slower than might have been expected because of high wage rates. He cited a Labor Department study that found that unskilled manufacturing labor here was paid 103 per cent of the national average, compared to 79 per cent in central North Carolina cities.

"While Prince William County can attract local servicing and distribution industies, the ultimate magnitude of economic development rests with capturing competitive industries which might also consider a Farifax County or closer in location," he said.

The Springfield area, on 1-95 and near the Beltway, is currently the most active industrial development area in Northern Virginia with Tysons Corner dominant in the office market, he said.

MacDonald termed his report "not overly optimistic. We don't want to lead you astray."

"We can go astray without your assistance," quipped Board chairman Alice Humphries, who, when told a mroe detailed written analysis would be available, asked. "What makes you think we want to see any of that in writing?"

The county has been offered 11 sites outside Manassas, including four near Manassas, three near Independent Hill in the center of the county and four near Lake Ridge in the eastern end of the county.

Supervisors from the populous east end of the county have often contended that the courthouse should be more centrally located.

O'Malley found the terrain at the Lake Ridge area sites generally undesirable for development and said that the locations near Manassas offered the county little opportunity for controlling growth in the surrounding area.

The consultants found that two Independent Hill sites along Rte. 234, which crosses the county from 1-95 in the east to 1-66 in the west, are centrally located and by bringing water and sewers into the area, would open up a major area to growth.

But they concluded that there is so much industrially zoned land available in superior locations closer to Washington on the Beltway, 1-95 and 1-270 that significant industrial development was still some years away in Prince William County.

Without a strong economic justification to back up moving the courthouse, the Supervisors appear to be unlikely to propose a move and an expensive new bond issue to the public in November when state bond and school bond referendums are already on the ballot.

Howere, there still seems to be a majority on the seven-member Board in favor of a move, and it it possible that the voters might be asked to approve such a step in a special election in January. The board has directed O'Malley to concentrate on the Manassas and independent Hill locations in future studies. The Supervisors are under strong pressure from the circuit court to build a new jail and had hoped to make a courthouse decision quickly in order to begin construction on the jail.

If they are unable to decided on a courthouse site outside Manassas, they may have to go ahead with the jail in the city, a step that would make a later move away from the present county seat even more difficult.