It had not been a good week for Interior Secretary James G. Watt.

Northern Californians had increased their assault on his hopes to open their coastline to offshore drilling and the word was out that the White House had taken the final decision on the politically volatile issue away from him.

The conservative National Wildlife Federation had called on President Reagan to fire him. Friends of the Earth, a more liberal environmentalist group, leaked Interior Department memos indicating that Watt was hoping to open National Recreation Areas to hard-rock mining, creating another furor.

Congressional Quarterly, a weekly journal that keeps an eye on Congress, published a report that told of his offending committee chairmen, threatening members of the appropriations committee and "relishing" clashes that were stalling his programs on Capitol Hill.

At a midweek news conference Watt found himself bombarded with questions about whether he was quitting and when, whether he had become a political liability to the Reagan administration and if his fundamentalist views on the Second Coming were interfering with his duties as keeper of the nation's lands.

Now he was sitting, rather impatiently, while House Interior Committee Chairman Morris K. Udall (D-Ariz.) criticized his "hasty and questionable schemes" and gave him a philosophical lecture about an earlier administration that "came to Washington with a 'can do' attitude [and] neglected to do its homework."

That administration, Udall said, was the one Watt's team replaced and it ended up with a "didn't do" record.

Watt, who had made it clear he plans a revolution at Interior and that such radical movements are not made of methodical decisions and polished compromises, bristled briefly as Udall summed up: "You may well discover the truth in the old adage: 'Sometimes, the long way around is the short way home."

Watt, after such a beleguered week, was trying to be on his best behavior yesterday. Still, he leaves the impression on Capitol Hill that he finds congressional hearings, like this one on his plans to reorganize the Office of Surface Mining, more an imposition than an obligation.

Quickly, he fired back at Udall that the chairman was "nitpicking" his decisions, that good government would be better served by holding one major "oversight" hearing on the mining changes instead of a series of "piecemeal" hearings in which he had to justify such decisions as moving an OSM office from Denver to Casper, Wyo.

Udall stared back unruffled and replied that it was difficult to hold an oversight hearing until Watt's nominee to head the mining office was confirmed by the Senate, meaning the secretary's policies were moving a bit faster than his appointments.

Watt, changing field, soothingly said a moment later, "I'd like to keep you in harness, Mr. Chairman."

Udall replied that the best way to do that might be to spend more time consulting with the congressional committees instead of confronting them. "All of us feel a little ambushed," Udall said.

Udall then said other congressional leaders, including Rep. Sidney R. Yates (D-Ill.), Sen. Henry M. Jackson (D-Wash.) and even Sen. James A. McClure (R-Idaho), a philosophical ally of the secretary, were feeling left out, too.

Watt smiled wanly, as if the week were getting long. "I have learned after six months of combat," the secretary said, "that you should be pestered by me much more often." He then promised that he would protect the environment, would not gut the surface-mining laws and would consult more with the Hill.

He was so conciliatory during the rest of the 2 1/2-hour hearing that Udall finally conceded that the "sensitivities you have expressed . . . are different from the reputation you have developed in this city."

But life is not simple. Rep. James Weaver (D-Ore) remained unimpressed. He asked Watt just two questions.

"Are you approaching [policy on] the Office of Surface Mining on the basis that the return of the Lord is imminent?" Weaver asked, quite abrasively in a reference to that early Watt statement about the Second Coming.

Committee Republicans gasped, even snorted. Watt paused.

"I'm surprised at you, congressman," Watt replied. "I have taken an oath to follow the law."

"Does the imminent return of the Lord have anything to do with that?" Weaver pressed on.

Watt paused again. "My religious freedom is guaranteed under the First Amendment," he finally replied, as if this were a week that should have started on Friday.