Too much intelligence

President Reagan and his national security adviser, William P. Clark, have thrown themselves a boomerang in their attempts to control news ''leaks'' and the flow of government information generally.

There have been a series of well-publicized fiascoes, the most recent of them an attempt to make the reporters who cover the Pentagon sign a secrecy pledge that would have made them an extension of the military propaganda apparatus. Earlier, the chairman of the Joint Chiefs of Staff and the secretaries of the Army, Navy, and Air Force were humiliated by being subjected to a lie detector test, part of a search for supposed culprits who had released what now turns out to be accurate budgetary information.

Behind the smoke generated by those episodes and others is a valid issue - the management and protection of what are vaguely referred to as ''intelligence sources.'' In fact, almost all such ''sources'' are technical means of collection lumped together in a category called ''special intelligence,'' or ''SI.''

Access to this body of information is by grant of special ''SI'' clearances to people who have been cleared for access to ''Top Secret.'' Because of the extra amount of investigation involved, such SI clearances are very expensive.

Congressional investigations in the 1970s and more recent statements by Adm. Bobby Inman and other intelligence ''insiders'' reveal a major problem with special intelligence. In short, there is too much of it.

The largest problem is with the ''signal intelligence'' (also called ''SI'') produced by the National Security Agency which Admiral Inman once headed. This huge organization picks out of the airwaves every day millions of telephone conversations, messages from embassies, and a mass of routine commercial traffic. Much of this daily ''take'' is distributed under elaborate and enormously expensive security precautions to the thousands of people throughout the government who hold an SI clearance.

Special rooms are necessary for storage of SI materials. These must be guarded 24 hours a day and ''swept'' periodically, and expensively, to protect against electronic ''bugs.'' It was this extreme concern with SI security that produced what were, in effect, two separate commands aboard the USS Pueblo when it was captured by the North Koreans in 1968. That, in turn, led to failure to destroy much that might have been kept out of enemy hands.

Because NSA does very little analysis of what it passes on, the task of sifting through this huge mass of material is left to the recipients.

Now the truth of the matter is that most of what the people with SI clearance know is gained from the open press and radio and television broadcasts. For one thing, most of what comes in from NSA is outdated by the time it gets through the bureaucratic mill, irrelevant to begin with, or so turgidly written and poorly printed that it is almost impossible to read. But the SI clearance - with its telltale specially colored badge - has become such a status symbol throughout the government that unless you hold the badge and are seen to be rummaging through the SI ''black books,'' you are just not with it in the eyes of your own colleagues and especially in the eyes of rival agencies.

Since most of the people who hold SI clearance are in high military and civilian grades, we are talking about a daily wastage of millions of dollars.

Generals and such are relieved of plowing through the ''black books'' by the employment of ''black book officers'' who sift through the daily files and whisper whatever nuggets are gleaned into the chief's ear. Since that doesn't keep the black book officers fully employed, they tend to tramp up and down staff corridors looking for ''cleared'' people to whom they can impart what they always seem to feel will be earth-shaking news. At $30,000 to $40,000 per year, they are expensive messengers.

The inevitable product of this steady expansion of often useless material and of access to it is a growing carelessness. It was possible for years at the US Army War College, for instance, to gain access to SI briefings simply by taking an SI badge from jackets students left hanging in the post gymnasium during their noontime workout.

If Mr. Clark were truly concerned about protecting valid secrets and saving money at the same time, he would concern himself less with the press and more with this increasing problem of SI abuse and mismanagement.

So while Mr. Clark and his boss are barking and growling around the front door of the White House, the great swamp of expensive and largely useless information grows apace, suffocating in the process valid security concerns.