After an uncommonly dry season, a surge of musicals is about to hit Broadway. How thirsty the parched have been was illustrataed by the wild reception given the reigning queen of musical comedy, Carol Channing, when she returned in "Hello, Dolly!" for an Actor's Fund benefit opening at the Lunt-Font-anne last Sunday.

Actor's Fund audiences are alert to all nuances. Cheering Channing at her entrance were such working stars as Yul Brynner and Constance Towers of "The King and I," Dorothy Loudon of "Annie" and Eartha Kitt of "Timbuktu." They have beendolding the musical fort while such starsas Angela Lansbury, Robert Preston, Della Reese, Fred Gwynne and Frances Sternhagen prepare new musical roles sand Stephen Sehwartz, of "Godspell" and "Piphin," works on "Working."

Those people blacked out behind Bella Abzug's floppy red hat in the sixth row center didn't seem to mind because much of the time everyone was standing. From Channing's entrance on a horsecar reading a newspaper, the evening became a parade of standing ovations.

With a single exception, the critics reached for all the superlatives in the reviewer's trade; the Times man, however, concluded that, "The original has been meticulously recreated" to the point of being "entombed in this Mandarin like project."

The fact is the reverse.The Houston Grand Opera, co-sponsor of the production, has accented Jerry Herman's music over the Jack Craig adaptation of the Gower Champion dances, which remain marvelous. An overture has been added, and instead of csting comedians in the romantic roles, there are splendid vocalists. With Florence Lacey and Lee Roy Reams to sing "Ribbons Down My Back" and "It Only Takes a Moment," those, "Sunday Clothes" and others reveal freshets of melody originally passed over. Houston's emphasis on the score recognizes Herman as a major musical stage composer. It's time fresh hearaings were given his "Dear World" and "Mackand Mabel" scores.

Herman is working on several new projects. The soonest to arrive is likely to be an adaptation he and his "Dolly" librettist, Michael Stewart, have made from "Jacobovsky and the COlonel." S. N. Behrman's English version of a Franz Werfel play seems an unlikely source, but then I felt the same about the potentialof "Pygmalion" before it became "MY Fair Lady."

The score also is the surprise element of "On the Twentieth Century," the musicaliztion of the Hecht and MacArthur farce of the '20s "Twentieth Century." Why the addition of "On the" to the title? A dominant investor, it is said, was told by her numerologist that for it to be a success, 21 letters in the title were vital.

Betty Comden and Adolph Green contributed the lyrics and book and Cy Coleman the score. The stars are Madeline Kahn, who combines a beautiful soprano voice with wit and beauty; John CUllum, a ine singer who isn't afaraid to act, and Imogene Coca, as free and inspired as ever. A relative unknown named Kevin Klinee reveals brilliant comicskill in this yarn of egoists on the famed Chicago-New York train, ingeniously designed by Robin Waganer, so often an Arena Stage designer.

Coleman's score, which caught only condescending attention, seems to me hilarious. Much in the way Cole Porter, in "Kiss Me, Kate" micked a single genre with "Wunderbar," Coleman's entirescore mocks all the musical styles of a stage and screen generation. Even the orchestrations are amusing for bravura arias, duests, trios, quartets, quintets, sextets and choruses. Since people persist in singing Porter's absurd line, "Gazing down on the Jungfrau" seriously, Coleman's staire may strike only a few, but how delighted they'll be to recognize exactly what he's doing.

"Timbuktu's" New York reception was much as it was here, admired for its costumes and melodies if not for essential quality. People who relished "The Wiz" will be giving it a hopeful try if only because choices this season have been so limited unless you go back to "A Chorus LIne" and "Grease."

But others are on the Horizon.

Presenting Della Reese in her first Broadway role, "The Last Ministrel Show" will begin previews March 30 at the Wilmington Playhouse. A Washington booking was sought but the city hasn't enough stages to supply the demand.

Also making his theater bow with this show is novelist Joe Taylor Ford, whose heroine is Black Sally, head of a troupe of 11 minstrel men. It's set in Cincinnati, Vintage 1926, and the minstrel troupe is about to end a 25-year run. The concept is of a musical within a play, the songs all being familiar ones of the period under the musical leadership of Howard Roberts, with Donal Mckale as director. It will go April 11 to Philadelphia's Locust Street Theater to open in New York April 24.

Robert Preston, the original "Music Man," returns as "The Prince of Grand Street," a musical about an aging idol of the Yiddish Theater's golden days on Secon Avenue. BOb Merrill has one book, lyrics and music and Gene Saksis staging it for producers Robert Whitehead znd ROger L. Stevens, the latternot wearing his Kennedy Center hat. It is trying out at Philadelphia's Forrest Theater through March 25. Boston follows March 29-April 29, before the opening May 11 at Broadway's Palace.

Angela Lansbury, who in recent years has gone from "Mame" to "Hamlet" (as Gertrude), choosesanother of those switches that come so naturally to British players, less so to Americans. When Brynner and Towers take a three-week holiday starting April 11 from "The King and I," Lansbury will become the melodic schoolmarm created by Gertrude Lawrence.

Brynner standby Michael Kermoyan, who has headed companies as the King, ill take on the Siamese ruler but, as was the case originally, Anna will again become the major role. The betting is that Lansbury will be well worth seeing. Brynner and Towersreturn May 1 to elebrate the revival's first Broadway birthday, but what's to keep Lansbury from playing it in London, where the Brynner King has a future date?

A highly unusualmusical tryout is going on unostentatiously at LOnga Island's Northstage Dinner Theater, Glen Cove, here Fred Gwynne and Frances Sternhagen are testing "L ook Homeward, Angel." Gary Geld and Peter Udell have contributed lyrics and music to Ketti Frings' dramatization of the Thomas Wolfenovel. It may moave into New York come spring.

Once set for testing at Arena Stage, "Working" is the Stephen Schwartz musicalization of Studs Terkel's fascinating book on ordinary people in ordinary jobs. After a test production at Chicago's Goodman, it has escalated into an expensive concept, with James Taylor, Micki Grant and Mary Rodgers among the creative contributors. Arena's Marjorie Slaiman is doing the costumes.

Slaiman's costumes also are a part of Christopher Durang's "comedy with music," "A history of the American Film," so captivating last spring at the Kreeger.Moreplay than musical, Durang's novelty still uses music. It opens April 27 at the 46th Street Theater.

Finally, there's another musical novelty, Bob Fosse's "Dancin'," a pure dance treaatment ranging from the music of J.S. Bach to that of Neil Diamond. Strenuous work proceeds in Boston, with the New YOrk bow March 27 at the Broadhurst.

Waiting till fall are other projects originally scheduled this season, among them "Sunset" "King of Hearts" and the Judith Jamison-Cab Calloway show once listed for the National as "The Only Game in Town." Now it's got a new title: "The Only World in Town." Did a numerologist order that added letter? On such delicate subleties our musical theater persistently teeters.