Leaving the August somnolence of Washington behind, Interior Secretary Donald Hodel set off on a 31-day swing through the West yesterday that will take him to 10 states, nine national parks and assorted monuments, wildlife refuges and water projects.

Hodel said he has already visited all of the parks on this tour, but his conversations with members of Congress persuaded him that "if I haven't seen it as secretary, I haven't seen it."

Between fly-fishing in Yellowstone and mule-packing in the Grand Canyon, Hodel has set aside time for tete-a-tetes with the governors of Utah, Wyoming and Nevada, a speech to the Western Governors' Conference in Honolulu and six days of town meetings in California on the contentious subject of offshore oil leasing.

Hodel and a group of California members of Congress announced a tentative agreement on oil leasing last month, with the department promising to declare 36 million acres off limits for 15 years in return for an end to a congressional moratorium that has stymied the administration's plans to increase oil exploration off California.

But the pact isn't backed by everyone involved. State officials contend that the agreement would still allow drilling in environmentally sensitive areas, and the oil industry is angry because of the number of tracts that would be excluded.

Hodel, taking his cue from the traditional pronouncements from Capitol Hill about this time of year, said he was optimistic that an agreement would still be reached -- just as soon as he gets back to Washington in September.

MINE? WHAT MINE? . . . Adding another dimension to the controversy over how well the Office of Surface Mining is doing its job, the Tennessee Valley Authority has reported that a significant number of its coal contractors appear to be in violation of the federal strip-mining law.

The TVA discovered that unhappy circumstance when it launched its own investigation of strip mines in light of "questions about inspection and enforcement practices" by federal and state agencies. Investigators checked 113 mines and found 21 percent of them engaged in mining practices that "resulted in varying degrees of environmental impacts," including some outright violations of federal law.

TVA investigators were also surprised to find that 26 of the mines they went to inspect were inactive or nonexistent, and four others were incapable of producing the tonnage specified in the contract. The finding suggests that the coal was coming from unauthorized sources elsewhere.

TVA coal contracts can be canceled or suspended if the mine operator isn't obeying the law, but the TVA said it relies on federal and state records to weed out the bad actors.

Federal and state mine inspectors had issued a written notice of violation at only one of the 14 sites where TVA inspectors found obvious violations of the law. According to the TVA report, state officials explained that inspectors are encouraged to be "flexible" on such enforcement actions in order "to maintain a good working relationship with the operators."

SURF'S DOWN . . . After six years of fun, fun, fun followed by something less than good vibrations, the National Park Service is thinking about getting out of the Fourth of July rock concert business.

Spokesman George Berklacy says that the park service is considering a "fireworks-only" celebration in 1986, scrapping the music fests that have featured the Beach Boys four times since 1980 and drawn ever-increasing crowds to the Mall.