No one expected it and now that it's happened no one really quite knows what to do about the small section of the Green River starting at Flaming Gorge Dam.There will be days this summer when the seven-mile stretch will resemble a city intersection at lunch hour. There will be parking problems, crowded trails, traffic jams, or in this case boat jams, and angry pedestrians, or in this case fishermen.

There will be days this summer when upward of 1,200 people will be practicing their recreation on this one part of the river, while the rest of it goes flowing on with little or no notice. On any given day there will be rafters, fishermen on land and in boats, hikers, campers, artists and photographers . . . rafters will have confrontations with fishermen, and fishermen with rafters.

Suggestions for controlling problems ranged from installing traffic lights on pine trees at busy river bends, to renting space on a per-inch basis. It is unlikely, however, any noticeable change will take place soon.

It will take, says David Keddy, district superintendent of recreation for the U.S. Forest Service, at least a year and a half to complete studies and gather public input before any decision making can begin.

"We are going to have to regulate it, but we have to decide when and how much? Do we issue permits? Go to slot management where we let fishermen on certain days, boaters other days? What level of use do we allow? How do we handle the shore fisherman? And the boat fisherman? There are a lot of questions to be considered and we don't want to make any wrong decisions at this point."

Several things go into making this the most popular piece of river in Utah. Three of the main ones are: 1. It's one of the most beautiful pieces of river-front property in the state; 2. it's very accessible at two points, making it ideal for rafting and fishing; and 3. it has one of the highest fish populations of any river in the country.

Because of the quality of the water and the landscape, and because of the easy accessibility at the dam and Little Hole, and because there are no major rapids to make rafting dangerous, the river has become very popular with rafters. This summer there will be days when over 200 rafts will be launched below the dam and picked up at Little Hole.

And there will be, some intentional, some not, run-ins between rafters and fishermen. The mere nature of raft trips - splashing water, thrashing paddles and excited passengers - aggravates the quiet, intent fisherman.

Keddy says some run-ins between the two groups have been serious, boats sometimes forcing wading fishermen to move, butsometimes not fast enough.

Then, too, there are 14 outfitters licensed to guide fishing trips on the Green. Each outfitter is allowed four guides. Given that, there could conceivably be another 56 boats on the water, although a more realistic daily number would be around 40.

Day use from hikers, campers and sight seers, again because of accessibility and scenery, is also increasing.

Use by fishermen is also increasing. Four years ago, after changes in fishing regulations, no one had any idea the river would eventually suffer from traffic problems. Faced with quality instead of quantity under strict new limits _ two trout under 13 inches and one over 20 inches _ fishing pressure dropped from 128,891 man hours put in between May and November, to 71,806 between 1984 and 1985.

Reacting to the new limits, the fish population soared. Now it has one of the highest populations of any river in the entire country. A river, for example, with a few thousand fish per mile is considered good, and one with 5,000 to 7,000 fish is revered. In the spring of 1986, Steve Brayton, fisheries biologist for the Utah Division of Wildlife Resources, says spring population estimated near the dam were 9,288 fish per mile and seven miles down at Little Hole, 7,481 per mile. In the fall, after planting and hatching, numbers jumped to 21,036 and 11,636, respectively.

This spring, population estimates were 14,564 near the top, and 9,717 at Little Hole. Fall numbers are expected to hit an all-time high. Fishermen counts are also soaring. Earlier this week, on what was called a very slow day, one of the slowest since early February, over a 100 fishermen, most throwing flies, lined the shores or floated in boats. In a few weeks, after Memorial Day, two to three times than many will fish there almost daily. According to Brayton fishing pressure used to slow down in the winter, now even during the off season fishing pressure is high.

The reason is, of course, because of the fish. They are, by fishing standards, big and plentiful. It's nothing to see large schools of big cutthroats, rainbows and browns holding in the shallows, and ignoring fishermen's enticements.

On an average day, a good fishermen reports Larry Tullis, fishing guide for Angler's Inn, who in the past three years has fish the Green over 150 days, can catch and release 30 to 50 fish.

Less experienced fishermen have a more difficult time. According to Tullis, the Green River fish are educated.

"With the large number of fishermen fishing the river, they've seen it all," he said. "They see the strike indicators now and they know a hook is close by. If it isn't natural, if the presentation isn't just right, they won't take it. This is a river you have to learn to fish, but once you do there is none better in the entire country."

Both Brayton and Keddy said there was no way they expected this interest in the river. Keddy said they expected seven to eight percent growth, "instead it doubled in one year.

"Now it's going to be a real challenge to provide what the people want, and in the proper ratios. Eventually, I'm sure, there will have to be a fee on the river, but when we do that then the demand for services goes up . . . pave the road to Little Hole, add flush toilets to be able to handle all the people, and water . . . water, believe it or not, is one of our big problems."

Certainly, there is little doubt that pressure on the section of the Green River will increase, for as Keddy said, "because of the quality of the water and the fishing, nothing can compare to it."