The U.S. Court of Appeals here ruled yesterday that construction of a new D.C. jail did not cure Washington's detention problems and ordered close judicial scrutiny of the facility to protect prisoners awaiting trial from "deprivation, neglect and degradation."

In a 2-to-1 opinion, the appeals panel strongly reasserted its authority to act on constitutional issues involving jailed defendants and gave specific standards under which people should be detained pending trial.

In his long opinion, U.S. Circuit Judge David L. Baszelon described the city's history as one of administrative inaction and mismanagement of the jail, and suggested that new regulations for the handling of pretrial prisoners be drawn on the judicial rulings in the 7-year-old case.

". . . Ultimately it is only with the whole-hearted cooperation of jail administrators that the constitutional rights of pretrial detainees can be protected," Bazelon said.

U.S. Circuit Judge George MacKinnon sharply dissented from the decision, saying that all of the prisoners' complaints in the original lawsuit had involved the century-old D.C. jail which has now been abandoned and the case should therefore now be dismissed. He accused Bazelon and U.S. Circuit Judge Harold Lenenthal of agreeing to a situation in which the courts "more or less take over the management of the new jail on a continuing basis."

The two majority judges "are attempting to make a whipping boy" out of the D.C. government defendants, who have little control over the number of persons put in jail by the law enforcement machinery, MacKinnon said.

"Judicial intervention into jail operations is justified only in extraordinary circumstances," he added, claiming that no such circumstances have been shown yet to exist in the new jail.

The District government had argued strongly that the case involving D.C. jail inmates should not be in federal court here, but should be resolved by the local court system whose judges put the bulk of the inmates there in the first place.

In rejecting the city's arguments that the situation did not require federal judicial intervention, Bazelon said it was true that federal courts "must practice special restraint" in such areas.

"However," he said, "a federal court may not shave the requirements of the Constitution to fit the desires of local officials, nor should it continue to accord these (D.C. government) defendants special deference in the fashioning of relief when the presumption of good faith has proved misplaced."

Bazelon's opinion included a long discourse on the special situation in which most defendants placed in pretrial detention facilities find themselves - not yet convicted of a crime and presumed innocent, but in jail, undergoing the same type of punishment they could receive if ultimately convicted.

Therefore, Bazelon said, it is important that such defendants be held only in the most proper and legal manner while at the same time the government can be assured they will show up for trial and the community can be protected.

He recounted the now-familiar tales of filth and discomfort at the old jail and said it was clear the overcrowding there violated the constitutional rights of persons held pending trial.

In upholding earlier rulings by U.S. District Chief Judge William B. Bryant, Bazelon said the lower court was "fully justified" in finding that the D.C. government's "grudging resistance, the ineffectiveness of their previous efforts at compliance, and the flagrant and shocking character of their past violations" required continued judicial supervision.

Bazelon said Bryant should hold further hearings to determine if overcrowding was beginning to occur at the new jail, and, if so, take appropriate action to control it. In addition, Bryant should "apprise himself of the likelihood of future infractions," Bazelon said.

In some specific areas involving standards at the jail, the appeals court:

Upheld Bryant's order that a clas-jail residents be provided clean clothing and bedding once a week.

Approved a finding by Bryant that some recreation is required for pretrial detainees, but asked him to determine further specifically what the quality, duration and location of the recreation should be.

Upheld Bryant's order that a classification system be devised for inmates at the jail, with further study of the possibility that some inmates will be allowed now-banned "contact" visits where they can talk to visitors without the use of protective barriers.

Asked Bryant to give the legal and factual basis for his order that jail food handlers be given medical examinations every 30 days.

Upheld Bryant's requirement that persons exhibiting mental problems be examined within 24 hours and transferred out of the jail within 48 hours if found to be mentally ill.