The spring Blue-winged Olive (Baetis) hatch is no secret. Everybody knows it's the first good mayfly hatch of the year on most trout waters in the West. If conditions are right, you can have good fishing, maybe even your best day of the season.

The trick is finding a place where the weather, the water, the trout, and the insects are willing to cooperate and let you enter dry-fly Nirvana. If you are tired of finding your local waters too cold or too muddy, or hearing that the hatch is already over, or late this year, or that fish populations are down because of excessive harvest or whirling disease, think about tipping the odds in your favor this spring.

Imitate spring Blue-winged Olives (dun shown above) with #16-20 Blue-winged Olive Thorax, Parachute Blue-winged Olive, Sparkle Dun, or Parachute Adams.

In late April and early May this year on Utah's Green River, the water will be clear with temperatures in the mid-40s. While I can't make predictions on the weather (Blue-winged Olives hatch best on overcast afternoons) I can say that with 8,000 to 14,000 trout per mile, you're likely to run into more than a few fish willing to eat a dry fly. It's as close to a sure thing as you're ever going to get.

Like the other famous tailwater fisheries of the West, the Green River flows clear and nutrient-rich from a man-made impoundment. Unlike other tailwaters, the Green's Flaming Gorge Dam has been outfitted with selective withdrawal structures, a multi-million-dollar apparatus that allows dam operators to draw water from whatever level of the reservoir is most favorable to recreation. What this means to anglers is that on the Green River, much of the guesswork normally involved in being in the right spot at the right time is removed. There's little guesswork here. Mark it on your calendar. The Green River is the place to be in late April and early may.

Red Creek Rapids (above) is several miles upstream of Indian Crossing (just downstream of the Pugmire Pocket campsite) and has a Class III whitewater designation. Floating this stretch is recommended for experienced oarsmen only. The red arrows indicate the author's preferred route through the rapids in high water. Stop on the right bank just above the rapids, climb the overlooking bluff, and scout your own route in all cases. Many boats have been destroyed on this rapid. Navigate at your own risk.

In early April, when the surface of the reservoir begins to warm, dam operators open the intake gates closest to the surface (40 feet under) and spring fishing officially gets underway on the river below. While the water is at first only imperceptibly warmer, year round guides agree there is an immediate and obvious change in the behavior of the fish once the gates are opened.

"Maybe it's zooplankton, or there's less nitrogen or more nutrients in the water," Trout Creek Flies owner Dennis Breer told me. "Whatever it is, it sure makes the fish act less like winter fish. The trout are more active and they get redistributed throughout the river into feeding lies, instead of podding up in their winter holes."

While Blue-winged Olives (BWOs) often start showing up sporadically in late March, they become more common after the selective withdrawal structures are opened, and peak during the last week of April and first week of May. In unusually cool, wet years, you still may see a few of the bugs popping in early June, but normally it's over by the end of May.

The first heavy hatches are found in the lower reaches of the river and as the water warms they will become more frequent closer to the dam. The first Blue-winged Olives of the year are #16, and as the hatch progresses, duns become more diminutive. Although #18 is by far the most common size, you'll see a few stragglers in late May best matched with a #20.

Overcast skies will often trigger the heaviest hatches, and encourage the fish to be a little bit bolder. A thick late-morning midge hatch is perhaps the best indicator of things to come, as both bugs seem to prefer hatching in similar conditions, and the midge hatch can really get the trout focused on the surface. If these conditions come together for you, get your lunch finished in a hurry. You'll soon see dozens of large trout nodding at you from every little backeddy, rows of noses poking out along the foam lines, and hundreds of fish rising in the flats.

Blue-winged Olives hatch in the afternoon. Midges often hatch earlier in the day, especially during the early season (April), and bring as many fish to the surface as the BWOs. Use #20 Parachute Adams, #18 Griffiths' Gnat, or Midge X to imitate the clusters of midges trout feed on.

If you have the bad luck to encounter bright, sunny weather, all is not lost. Just because you don't see any bugs, or fish rising, doesn't mean you can't catch your fish on top. Green River trout are very surface oriented. Sometimes the only reason you don't see them rising is because you haven't put you fly over them. Give them an opportunity to rise, and they'll very often take you up on it.

I've spent sunny April afternoons catching fish after fish on Blue-winged Olive patterns when there were no, or very few, duns on the surface. The fish seem to love these little delicacies and will sometimes ignore a heavy midge hatch, and then pounce on the first Parachute Adams they see. I don't understand it, but I like it.

Possibly the most amazing and frustrating spectacle you may see this time of year is a blanket hatch. Incredibly, this hatch may ruin your day. Sometimes the Blue-winged Olives will become so thick, and the trout so focused and selective, that it makes catching them all but impossible. Your fly may be just one of a hundred food items in a trout's feeding lane at any given time. When you consider that a trout will often eat one bug, let a dozen or more pass, and then eat another, you realize your chances are pretty slim.

In this instance, try to measure the rhythm of the fish you are after, and make your fly appear in his window of vision just when you expect him to rise next. Keep giving it to him in the perfect spot and at the perfect time over and over again and you may eventually succeed. The most effective patterns are low-riding, flush-in-the-film flies like a Parachute or Sparkle Dun Blue-winged Olive. You could also tie on a Woolly Bugger or Stimulator, and try to find a fish with a little different appetite, but that wouldn't be matching the hatch, would it?

Because the Green flows through a rough, wilderness area, and much of it is canyon water, access can only be gained at designated boat launches. The top float, from Flaming Gorge Dam to Little Hole, is a seven-mile drift through a spectacular canyon with a 60/40 mix of rainbows and browns. Near the dam you'll find a lot more rainbows than anything else, and by the time you reach the take-out, you'll be deep into brown trout territory. The Little Hole Trail runs from one boat launch to the other, and provides foot access to this entire stretch of river. Those willing to walk more than a mile from each access will find the best fishing. The fish in this part of the river receive far more fishing pressure than anywhere else, and can be difficult to catch. Fine tippets, exact imitations, and careful presentations are always in demand.

Floaters are required to wear life jackets at all times on the Green, and first-time floaters should use extreme caution at all times. This is a popular white-water rafting destination and with good reason. Some rapids on this river can, and have, destroyed drift boats, and taken lives.

The middle river--from Little Hole to Indian Crossing--runs through nine miles of gentler terrain. There is no walk-in access here, but there are 19 public campgrounds with places to pitch a tent, picnic tables, and awesome fishing nearby. The camp sites are free, but you must sign up for them daily on a first-come, first-serve basis at Little Hole.

From Little Hole down, the river is a brown trout fishery--the wild descendants of trout stocked in the late 1960s. They are wild, colorful, free-rising fish that average 15 to 18 inches long. The rainbows in the upper river are a mix of stocked and wild fish. You may also catch a Snake River or Yellowstone cutthroat trout near the dam--which are also stocked--but these and brook trout make up less than 2 percent of the total trout population.
Rainbows are the most common trout species in the first seven miles below Flaming Gorge Dam. The farther downstream you float, the more brown trout (above) you encounter.

There is a marked decrease in both the trout and insect population in the extreme lower float, from Indian Crossing to the Colorado state line, but there is still some fine fishing here at certain times of the year, and many of the largest trout in the river live in this section. Through much of the spring, this section of the river is often dirty because of muddy water flowing in from Red Creek. In the early season, or any time of the year after heavy thunderstorms, anglers may want to avoid the water below Red Creek. (Red Creek flows into the Green several miles upstream of Indian Crossing.)

Those planning a trip to the Green River should pay close attention to Dennis Breer's (Trout Creek Flies) fishing reports. Dennis lives year round in Dutch John, Utah, and updates his reports weekly--more often if neccessary. His reports are the most current information available on the Green River anywhere. Guide services are available from Trout Creek Flies (800-835-4551) or the Flaming Gorge Recreation Service (801-885-3191) in Dutch John and through several Salt Lake City-area fly shops. River shuttles can be arranged by calling the Airport Shuttle Service (435-885-3338) or the Flaming Gorge Recreation Service. Flaming Gorge Recreation Service also owns the only lodge in town.