About 80 persons who were arrested Saturday during a District-wide crackdown on drug trafficking remained in custody last night after they were unable to post bond, D.C. officials said.

But as police continued to tally exact figures from the operation, called "C-note Sevenfold," officials of civil liberties groups questioned the legality of the massive police action and whether it would have a lasting effect on drug sales in the city.

Sixty-four men remained at the central police cellblock last night, according to officials, and an undisclosed number of women were still held at the D.C. Jail. Arraignments for some of those arrested are scheduled today in D.C. Superior Court, officials said.

Although final arrest figures were unavailable yesterday, Lt. Hiram K. Brewton said that 448 persons were arrested during hours the dragnet was in operation in each of Washington's seven police districts.

The 448 total, however, includes all arrests in the city during the approximately seven hours of the operation, which ended about 9:30 p.m., officials said, noting that 10 to 20 percent of the arrests were unrelated to operation "C-Note Sevenfold."

Deputy Chief James K. Kelly said a total of 290 persons were charged with drug-related offenses, mostly misdemeanors involving possession of marijuana and PCP.

Many of the other arrests were for minor licensing violations and and some involved disorderly conduct and driving while intoxicated, Kelly said.

The licensing charges generally stemmed from a series of roadblocks that were set up throughout the city.

Kelly said that the roadblocks were meant as "diversions" so that drug transactions could more easily be observed by undercover police in hidden observation posts. With attention of the public diverted to the roadblock activity, drug dealings were more detectable than they would otherwise have been, Kelly said.

The roadblocks were a hallmark of the operation and were used by most of the city's police districts. Several of the districts moved the roadblocks throughout the course of the afternoon and early evening. Police did not disclose many specifics about the operation, which included uniformed, undercover and plainclothes officers from all districts and the Special Operations Division. Additional administrative personnel assisted in processing those arrested.

According to information compiled from the individual districts, there were roadblocks at: 20th Street and Maryland Avenue NE; 16th and U streets SE; Sumner and Wade streets SE and along 14th Street NW at H and W streets and Florida Avenue.

Arthur Spitzer, legal director for the ACLU's Washington office, said yesterday that he objected to this stop and search tactic as unconstitutional. "If they can do it while someone is driving a car, I don't see anything to prevent them from doing it while someone is walking down the street or sitting in their living room," Spitzer said.

Police officials said yesterday that they were satisfied that the operation accomplished its main goal of temporarily disrupting the drug "marketplace," but acknowledged it will probably have little long-term effect on the lucrative drug business in the city.

"When you go into an environment that drug buyers and sellers feel comfortable in and you disrupt it, at least you disrupt sales for a while," Assistant Police Chief Marty M. Tapscott said yesterday.

"Those types of operations are effective for a short time, but it would be foolish of me to sit here and tell you that it's a long-range effect because it's not. Drugs will hit the street again and we will have to go back in again. Whether we'll do that on this scale is something to decide in future," Tapscott added.

The deputy director for the D.C. Public Defender Service also expressed concern yesterday about the legality of such an operation.

"There're certainly questions about the constitutionality of the procedures they're using," said W. Anthony Fitch. "Any time police engage in large scale or massive roadblocks or other sweep type action there has to be concern for whether the interests of citizens protected by the Fourth Amendment are being invaded.

"I hope this isn't repeated again and again because it seems even from the comments of police officials themselves, they seem to have expended major amounts of resources to obtain arrests of people involved in very minor offenses. There are much more serious ofenses the police should be concentrating on," Fitch said.

Police officials said they followed guidelines set by the Supreme Court in Prouse v. Delaware. The court held that police could establish roadblocks if the public was not unnecessarily inconvenienced and if every car was stopped.

In Saturday's operation, police said there were no long traffic backups, because they kept moving the roadblocks to different sites and did not search a person or a car unless they first arrested the driver for some offense such as not having a driver's license.

Cars were searched without prior arrests only when police operating from observation posts suspected that the occupants had been involved in a drug transaction, Tapscott said yesterday.