The rise and fall of the Mott Haven housing project is only a small part of the disaster beseting the South Bronx, but the cycle from ruin to ruin happened so fast, with so much waste and such confusion, that it merits a special place in the long, sad history of public housing failure.

In 1969, the rehabilitation of what is officially called the Mott Haven Housing Development Fund Project on East 139th and 140th streets began. Some of the buildings were gutted and abandoned less than two years after rehabilitation had been completed.

Others lasted five years before they were once again uninhabitable.

Roy Howard walks down East 140th Street pointing to derelict buildings and recounting how long they lasted. Of the 21 buildings in Mott Haven, seven are still occupied, 13 are abandoned and one was demolished less than 11 years after reconstruction began here.

Howard, the president of the tanants' association, has been fighting with extraordinary zeal against the project's managers and financiers since the troubles began, but fewer people share his dream and his effort. Only 75 of Mott Haven's 315 apartments are occupied. The families are trickling away.

Howard remembers the planning meeting in November 1967 when he and other tenants first saw blueprints for Mott Haven. The talk then was of flowers and trees.

Oh, it was a beautiful plan," Howard said.

As the flowers and trees became more and more remote, Howard clung to his memories of the original plan, nursing grievances accumulated over the years, telling and retelling them in letters and phone calls to President Carter, senators, congressmen, local politicans, bureaucrats and journalists.

His principal villain is the U.S. Department of Housing and Urban Development, which took control of the project in 1974 and became the owner in 1974 at the cost of $4 million -- the loan guarantee it put up for the rehabilitation work.

HUD has regulations for what it is supposed to do when it becomes the owner of a housing property, Howard notes. At Mott Haven, HUD ownership brought little improvement for the tenants.

Maintenance remained poor. In one absurd twist, the Consolidated Edison Co. sent notice to HUD that it would turn off lights in the hallway and other public areas because of nonpayment of bills.

"The credibility of the federal government and the integrity of HUD are long gone in the South Bronx," Paul Moore, the Episcopal bishop of New York, wrote to HUD recently. Moore has been trying to help residents of Mott Haven for three years. He expressed his anger in a letter to acting HUD regional adminstrator Oliver Leggett.

Leggett has assured the bishop HUD is aware of Mott Haven's problems and making every effort to provide "decent, safe and sanitary housing" there. Moore, like anyone who has visited Mott Haven, knows well HUD has made few such efforts at maintaning the apartments, which are simply unsafe and less than decent.

Tenants complain of holes in walls, faulty flues that allow soot into some apartments, water damage from leaking pipes and ill-fitting windows.

The tenants, however, are not the only ones who complain. "The buildings didn't come with holes in the walls," said one government official who blames tenants and other local residents for vandalism and thievery that degraded Mott Haven.

Howard agrees that security never was good, but he rejects arguments that the tenants themselves participated in the destruction. Some of the work inside the buildings was so shoddy that thieves could cut through partitions from a vacant apartment to an occupied one.

At the beginning about 80 percent of Mott Haven's residents were on welfare. Almost all that remain receive welfare. HUD has charged that tenants' refusal to pay their rent has speeded Mott Haven's decline, but Howard has files of rent payments that show that HUD gets almost all its rent automatically in direct payments from the welfare department without the tenants having an option to pay or not.

Both HUD and the tenants agree on one cause of trouble. Mott Haven has not had good managment. However, despite the failures of the management companies hired to run the project. Mott Haven is particularly depressing because while everyone agrees it is a disaster, no one can point out exactly where it went wrong.

In March 1978, the regional administrator of HUD, Thomas Apelby, said most of Mott Haven's five-story walkups would be rehabilitated a second time although a few might be so far gone they would have to be demolished.

Alan Wiener, area manager of HUD, said recently that rehabilitation plans have been dicarded. The only solution now is to tear down Mott Haven and start again, he said. "We're offering to relocate the tenants as well as to build new housing."

HUD and the remaining tenants led by Howard are talking past each other, however. Howard speaks of lawsuits and claims for past wrongs against tenants.

Under one HUD provision, Howard claims, tenants are due refunds from HUD on utility bills paid since the federal government took over as Mott Haven's owner in 1977.

Almost every Mott Haven tenant now is on welfare and paying rent by direct transfer of welfare funds to the project's manager. How can they fall behind in their rent if the rent money is paid automatically by the welfare department? he asks.

"At a certain point," says one man who is trying to help get talks going between HUD and the tenants, "tenants have to stop writing letters to the press and start discussions."

HUD officials say they have housing in the South Bronx that Mott Haven residents could move to, but Howard doesn't want to move. He still remembers the original promises of trees and flowers and he isn't ready to trust the dreamers of such dreams again.

Wiener says that tenants would have to move out at least temporarily even if an attempt were made at a second rehabilitation along the plans of the 1906s idea. "We've got a much better plan," he said.

Since the South Bronx -- including Mott Haven -- has lost population in the last decade, he prosposes building about 150 units to replace the 315. They should, he says, be two- and three-story buildings with inner courtyards protected from street vandals.

Howard may be exaggerating when he says he believes President Carter is taking an interest in Mott Haven, but New York's congressional delegation and local politicians are paying attention and trying to help find a solution.

But whatever the new plan drawn and the new federal money spent, one of the planners said, "they could be talking about the plight of the second Mott Haven 10 years from now."