"Sandy River, Oregon - Great Rivers

The Sandy River originates high on the slopes of Mt. Hood, located about 50 miles east of Portland, Oregon. The headwaters are beneath Reid and Sandy Glaciers at 6000 feet in elevation. From there the river flows due west through the Hoodland Corridor. It cascades past the communities of Welches, Brightwood and Sandy, then turns north to enter the Columbia River near Troutdale, which is 10 miles east of Portland, Oregon. At the mouth of the Sandy River, the Columbia River is still tidal.

The Sandy River is a geological product of the same dramatic forces that shaped the rest of the West Coast of North America. Her changeable personality is one of tectonic stress, explosive vulcanism, glaciation, torrential rainfall, the afternoon sun and the disintegration and regeneration of huge conifer forests. The river drops swiftly through rugged canyons. It has deep boulder-studded pools with clean, gray gravel bars often shaded by tall, wet green trees.

The major weather pattern flows from the Pacific Ocean and stacks the moisture-laden air against the massive slope of Mt. Hood. Here the atmosphere supersaturates and rain begins to fall. If you are a resident steelheader you tend to disdain days of hot bright sun and long for the misty cloud cover when steelhead come most readily to the fly. In the headwaters of this drainage it rains over 100 inches in over 100 days a year. This continual flush of clean water and the fact that no heavy industry exists in the basin keeps the Sandy very pure.

Summer rains are usually soft warm soakers, but winter storms can leave deluges of 10 inches of rainfall in 24 hours. The river is incredibly fluctual. Average mean flow is about 1,000 cubic feet per second, but the estimated flow on Christmas Day of 1964 was over 100,000 cubic feet per second. The character of the river is unpredictable. A few inches of water can change the holds. Twenty feet of water can change the whole river bed to the point that your favorite drift is now on the other side of the canyon.

Chinook from the Sandy The river bottom experiences terrific bed load shifts. Because of this, the aggregate never has a chance to compress and remains soft and very permeable - easy digging for salmonid tails if they belong to fish that are hardy and adaptable. These gravel-cleansing floods are essential to the health of the fishery. Because the riparian zone is in such good condition, the river drops and clears very quickly. It is fishable most of the time and fishes well from 700 to 4,000 cfs.

In most places the Sandy River's ecology is fiercely guarded by the canyon's residents. Nowhere else in the world does such a wild and scenic steelhead river flow through such a densely populated area. Wild adult steelhead are protected by catch-and-release angling regulations. This could allow a steady increase in wild fish over the next century.

In the frigid Arctic zone above timberline, several high elevation glaciers have survived on the flanks of Mt. Hood since the Ice Ages. During the summer months these glaciers feed the Hood River, the White River and the Sandy River with old water heavily laden with nutrient-rich volcanic flour. All of the rivers draining these glaciers turn white during the warmest months. They support an amazingly rich and diverse food chain comprised of organisms specifically adapted to their very tumultuous dispositions.

The largest glaciers naturally exist on the wet west side of the mountain. Sandy Glacier is the largest of these permanent ice fields and the Sandy is the largest of the Mt. Hood rivers.

River Keeper, Jim Barlow with Jan. wild steelhead

The Sandy starts as a rivulet dripping from the edges of the ice and collects in a boulder-strewn, steep-sided sand canyon. This section of river is called the Muddy Fork.

At the base of the mountain the Sandy is a brawling, boulder-strewn, plunge pool mountain stream. Some of the boulders are as large as automobiles. The river channel cuts through the featureless recent "Old Maid Flat" mud flow which is covered with a thick carpet of moss and lichens. The timber is sparse young Douglas fir. These are from seeds which landed on the barren pyroclastic sand soon after it cooled. This mud flow covered a living forest of much larger timber. Along the river bed many of these trees have become exposed and their slowly decaying trunks stand as ghostly sentinels to a long forgotten past.

In the past Mt. Hood has ejected many such bursts of pyroclastic sand and lightweight volcanic rock. These ejections cascaded down the steep slope of mountain creating vast alluvial fans which pooled inside a basin that was gouged by glaciers and is rimmed by the older basaltic volcanos. This formed a fairly wide flat valley floor about 15 miles long which extends from the mouth of the Clear Fork to the mouth of Alder Creek. In this 15-mile section the Sandy is joined by no less than 10 "class one," anadromous fish spawning tributaries, comprising about 90 miles of habitat.

These tributaries are the Clear Fork, Lost Creek, Clear Creek, Zig Zag River, Still Creek, Bear Creek, North Boulder Creek, Salmon River, Jewel Creek, Wild Cat Creek and Alder Creek. In turn, these creeks have unique tributaries of their own.

These small clear rivers rush from the steep slopes of the mountains surrounding this basin and extend into the valley floor. Here their gradient decreases dramatically. Though still swift, their velocity slows down and in the mellowing currents, small to medium sized gravel is allowed to collect in large volume. These deposits form an ever-shifting layer, laying loosely over a mantle of hard basalt. Much of the water in the river basin travels through an aquifer in this bed of gravel, providing maximum oxygenation for the spawn of anadromous fish. This upper river basin contains vast areas of spawning gravel for wild spring and fall chinook salmon, coho salmon, summer and winter steelhead, sea-run and resident cutthroat and resident rainbow trout.

Wild fish on a wild river - the Salmon The upper river basin has become a very popular sports fishery. Its intimate beauty appeals to all kinds of people. But, easy accessibility has posed real problems for whole populations of wild salmonids.

Floating
the Sandy takes skill

The Sandy River, though still a guarded secret among fly fishing enthusiasts, has the best year-round run of steelhead in the region. Its geographic location, topography and geologic history make it the perfect steelhead factory.

A blending of both hatchery and endemic stocks bring bright steelhead year-round. Probably at least five genetically different races of steelhead ascent the Sandy River each year.

Surprisingly, the size of the steelhead the angler will encounter varies little through the seasons. About 80% of the annual run are fish that have spent two full years in the ocean and will be 27 to 31 inches in length or seven to 11 pounds. About 10 percent are fish that have spent three years in the ocean and can be 32 to 39 inches long and weigh 12 to 20 pounds. About five percent are fish that have spent four or more years in the ocean and weigh 20 to 30 pounds. During the average year less than five percent of the steelhead will have spent one year or less at sea and weigh less than five pounds.

The largest and most vigorous run of wild endemic Sandy River steelhead enters the river mid-February and continues through May. The majority of these fish have a two year freshwater and two year ocean life cycle. Some of these fish will stay at sea for three or four years and are trophies from 18 to 30 pounds. From 3,000 to 5,000 of these beautiful fish spawn in the watershed. All are protected by catch-and-release regulations.

These fish are biters but not risers. Sexual maturity keeps them hugging the bottom, but this same sexual maturity makes these fish very territorial. A big black or red fly fished deep and slow is often the answer. Polarized glasses are indispensable for spotting and stalking fish.

Spawning fish are most visible. The angler should not bother spawning fish and one should be careful not to wade across redds. Pocket water or slots downstream from spawners may hold bright fish that will serve the sport much better. ~ Mark Bachmann

For a MAP of The Sandy River, click here.
For the FLIES for The Sandy River, click here.
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Credits: From Sandy River part of the Steelhead River Journal series, published by Frank Amato Publications. We greatly appreciate use permission.

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