DOCUMENTARIES CROWD THE SCHEDULE

The prime-time TV season doesn’t begin officially until Sept. 22, but competition among the networks’ first-run entertainment programming really begins two weeks earlier, on Sept. 8. Once that happens, documentaries are programs non grata . So, in a rush to grab the time while they can, the networks’ news divisions have scheduled four for the week of Sept. 1.

That’s the same number in one week that they’ve had on in the previous three months.

Which makes it all the more ironic that two of the programs are on the same subject: cocaine.

CBS will beat NBC to the punch with its cocaine documentary. “48 Hours on Crack Street,” anchored by Dan Rather, will be broadcast Sept. 2 at 9 p.m. NBC’s “Cocaine Country” arrives Sept. 5 at 10 p.m.

The other two network documentaries are scheduled for Sept. 3: “One River, One Country: The U.S. Mexican Border,” anchored by CBS’ Bill Moyers, at 8 p.m.; and “At a Loss for Words . . . Illiterate in America,” the first in a series of ABC reports about illiteracy, at 10 p.m., with Peter Jennings anchoring.

The two cocaine programs approach the subject in different ways.

For its two-hour broadcast, CBS sent “Evening News” anchor Rather, nine correspondents, 25 producers and 18 camera crews to New York City on Aug. 15-16 to look at the drug problems there.

NBC’s hourlong report, with Tom Brokaw anchoring, takes a more conventional overview, talking with drug experts, law enforcement officials, sports figures and First Lady Nancy Reagan about the scope of the problem and what can be done to fight it.

Cocaine also is the subject of a four-part documentary series that KCET Channel 28 is rerunning next week. Beginning Monday and continuing nightly through Thursday at 11 p.m., it will show “Cocaine: A Small Family Business,” a report on the cocaine trail from the plantations of South America to the streets of the United States.

NEW JOB: Former MTV hostess Nina Blackwood was scheduled to make her first appearance as a reporter for “Entertainment Tonight” Wednesday. She’s been assigned, not surprisingly, to the music beat, interviewing rock stars and anchoring a weekly music news report.

NEW HOSTS: Shelley Long, who stars as Diane Chambers on the NBC comedy series “Cheers,” will join David Letterman as co-host of the Emmy Awards telecast on NBC Sept. 21. Long won an Emmy in 1983 for her performance in “Cheers” and is nominated again this year.

Elsewhere, Robert Klein has been named by USA Network to host the cable TV talk show that Dick Cavett has been heading. With Cavett moving to ABC, USA Network will introduce “The Robert Klein Show” Oct. 3. It will air Friday evenings.

NEW LIFE: The critically acclaimed production of “I, Claudius” will return for another engagement on KCET Channel 28 next month.

The 13-hour British miniseries about the leaders of ancient Rome will air Thursdays at 10 p.m., beginning Sept. 11. It stars Derek Jacobi as Claudius, Sian Phillips as Livia, Brian Blessed as Augustus and John Hurt as Caligula.

After the miniseries played on the Public Broadcasting Service in 1977, it was syndicated to commercial stations, with some cuts made and Anne Bancroft added as host. It is the latter version that will be running on KCET.

NEW DIGS: In the final episode of “Dallas” last season, J.R. Ewing’s office was blown up by a bomb. Rather than rebuild, he’s moving his oil company to a new 70-story office building in Dallas.

Actually, it was real-life renovations on the downtown building that the producers have used in the past that prompted the move to the posh InterFirst Plaza building, which had been courting the show for more than a year.

“We figured since we had the tallest office building in Dallas, J.R. ought to be in it,” said Gayden Scott, a spokeswoman for Bramalea Ltd., which owns the new building.

Ewing Oil was provided with free rent and parking at the 70-story building during filming of the CBS series this summer, enticements that have become routine in the overbuilt Dallas real estate market.