The current of the Merrimac River, helping turn the giant waterwheels of the nation's first factories here 175 years ago, swept in a new wave of industrialization that forever changed America's agarian society.

The reverberation of rows upon rows of cotton gins, spinning wheels and looms - turning bales of cotton from the South into calico cloth all under one roof for the first time - became a symphony of mass production, sounding the beginning of the country's industrial revolution.

Those were the highwater days of the city of Lowell, where domestic and immigrant laborers spun cotton into gold for wealthy Yankee merchants, bringing decades of prosperity to this area.

Ironically, those same red brick textile miles of the nation's first planned industrial community are giving this downtrodden old mill town new hope now for the future.

Like James Cabot Lowell, the Boston merchant whose dream inspired the creation of this community 30 miles north of Boston, the city's latter-day pioneers have successfully parlayed their vision of a massive urban renewal project into the country's first national historic park, expected to draw 750,000 visitors a year.

The park was officially opened yesterday, amid the traditional hoopla of political speeches, as a monument to the industrial age in the heart of this once dying city of 92,000. President Carter signed legislation June 5 approving $40 million to renovate and preserve the history of this archetypal New England mill town.

The National Park Service, working with local and state officials in this unique effort to save the city and its heritage, plans to provide guided tours of the old textile mills and the network of 5.6 miles of canals which supplied water power for the factories.

Much of the scheme for the "living musesum" is still in the planning stages, and the park is not scheduled to be completely for about a decade.

"This is truly a cooperative three level venture between the federal government, the state and the city - a first for the National Park Service," said Lew Albert, superintendent of the park. "We are here in a supportive, cooperative role and not just as a bunch of federal bureaucrats come to sprinkle money around without getting involved - we care."

Until recently, however, many of the citizens and officials didn't care.

"We have the remnants of a once-great industrial empire," said Patrick Mogan, who led the local drive to convince his neighbors of the project's merits. "The people here were conditioned not to see the beauty of the city's ethnic and industrial heritage."

The city was established in the early 180s as a community of workers and machines that, in contrast to the British system of squalor and slums, was remarkably clean and pleasant.

New England farm girls, lured by the adventure of city life and money for their dowries, were recruited to work the machines from 12 to 14 hours a day. They were lodged in strictly chaperoned boarding houses, and forced to attend church services each week. They were also encouraged to improve their minds through lectures and classes given at a company-built hall.

The "nuns of Lowell" were later supplanted in the first wave of immigration by Irish, French-Canadian and Greek laborers. The lively multi-ethnic community still exists in the city.

But, as in so many northern industrial cities, manufactueres began the exodus to the South. Lowell fell into 40 years of economic decline, bringing the higher unemployment rate in the country and a sense of civic depression. The red brick textile mills with their gabled slate roofs were eyesores, a constant reminder of the city's economic decay.

"There is so much here, and yet it was a battle to get people in Lowell to feel the city was worth anything," said Rep. Paul Tsongas (D-Mass.), who shepherded the bill through the House. "There is still layer after layer after layer of doubt that we have to peel back before this project can become a real national success."