Only moments after Barbara Walters had reported on "millions of dollars in damage" from southern flooding, the "ABC Evening News" shifted to another topic: TV ratings. At almost the same instant, the "NBC Nightly News" decided to take up a very interesting if rather similiar subject - TV ratings.

And all this during what are fondly - no, religiously - known in the TV business as the November Sweeps, a key ratings period when audience total's will help determine the rates that can be charged advertisers for months to come.

Of course, networks and stations don't really sell time, they sell us, in large numbers, to the sponsors. In a way, the November Sweeps actually determine the bounty on viewers' heads.In the TV biz, this is a very hectic and exciting time. Viewers may feel a slightly less drastic quickening of the pulse, however.

The may even feel sweeped away by an unusual lethargy in the ratings heat of November.

True, the networks and stations do tend to stack their decks with premium attractions to lure big audiences. On Saturday, for instance, NBC will begin a four-night Big Event that promises to make most other Big Events look puny - the long overdue, nine-hour telecast of "The Godfather; The Complete Novel for Television," in which two recent movie classics have been re-edited into a new and fascinating TV epic.

On the other hand, quality stuff may be the last refuge of the networks during sweep time as well as any other time, particularly since it may be easier to lure crowds with sensationalism and smut. NBC tried that, too with last weekend's deliriously lurid "Aspen," a sex-and-violence jet set potboiler that, as it turns out, didn't draw quite as many prying eyes as the network had hoped.

What's more distressing than lousy entertainment, which we are probably all becoming numbly inured to anyway, is the way even newscasts are hyped up to meet the spirit of the sweeps. Ways are found to spice up the news, and get bigger ratings. ABC and NBC apparently feel that one way to higher ratings might be to do reports on ratings.

Whether these multi-part "reports," which began Monday, will include the fact that the news shows how to ratings pressure just as readily as the "San Pedro Beach Bums" do is doubtful. NBC was content on Monday to trot out poor old Lee Grant for more vituperations about the cancellation of her "Fay" series on NBC two years ago. Perhaps it was imagined that this would look self-effacing on the network's part. It didn't. It looked like yesterday's non-news today.

Meanwhile, ABC News has added a new wrinkle to the news ratings race: guest stars! Not just the political biggies that Walters is able to snare, either, but the kind of people usually relegated to couches and chairs ruled by Merv. Mike, Dinah and Johnny.

In promotional announcements aired last week. Walters promised viewers that the next night's newscast would include an interview with actress Anne Bancroft. Bancroft, conveniently enough, is now appearing as Golda Meir in a Broadway play. Thus does the talk-show plug make its way into a news show; another frontier falls.

We know that much of what passes for news in television is not news. It is information candy. But it's disturbing to be reminded that what should be news-generated decisions may in fact be sales-generated decisions. This is especially clear on local newscasts in Washington, where all three network-affiliated stations are now offering viewer-luring special series to commemorate exploit the ratings sweep period. News value of these series varies from some to none.

At WRC, the current series - an excellent one so far - is about "Depression." On WJLA, a three-part series begins tonight on "Playing Around," with reports on such sizzling, life-or-death topics bowling, skateboarding and hot-air ballooning. Next week, the same station's newscasts will feature reports on Washington after dark, which will cover hard realities like dope-dealing and prostitution on the streets.

On WTOP, Monday was the first night for a five-part series on cocaine which the station claims was two months in preparation. But the first installment, reported in hysterical Paul Harvey fashion by correspondent Pat Collins, could have been boiled down to one paragraph of a competent magazine article.

Collins spent most of the time trying to justify the series by attesting to the popularity of cocaine, which indeed other media have been attesting to for months. The tone of Collins' pitch was such that viewers who had not taken cocaine or heard much about it elsewhere must have gotten the impression that they were terribly un-chic for not having used it. Collins may have been so concerned with a hyped-up, sweep-time style that he forgot about the content.

Meanwhile, what was passing for news on WJLA included a bearded man telling what seemed to be jokes about TV programs that would follow the news on that station and others. His appearance was prefaced with a gung-ho side that said, "Coming Up: A Big Night on the Tube," although nothing he said gave any indication of a big night in the offing.

The small night on the tube that followed found viewers facing limited alternatives, partly because WTOP decided to pre-empt three good-to-excellent CBS network programs - "The Betty White Show," "Maude" and "Rafferty" - in order to prevent a brutal old movie, "The New Centurions," that had already been shown at least twice in prime time when a network owned it.

A station spokesman confirmed that the reason for this inspired burst of local programming was that the station makes more money from the showing of its own old movie than it does from the network fare, even when the network fare is entirely superior and, in this case, much less violent and abrasive.

It's infuriating when viewers are given no real consideration in such decisions and this can happen even, perhaps especially, during periods when stations and networks are trying to accrue as many viewers as possible. That is just the way television works. Or fails to work, as the case may be.

The misguided programming decisions are less serious, however, than the increased sweetening of what used to be newcasts - and during this ratings period that sweetening seems to be getting more excessive and distasteful than ever. There is more news" than ever on television, and yet less and less of it qualifies as news.

In time, we stand to become the most over-informed misinformed people on the face of the earth.