A LEGENDARY TROUT STREAM IN BIG SKY COUNTRY IS THREATENED BY ITS DAM

Montana's Madison River is the most celebrated trout stream in North America. This statement is attested to by thousands of anglers and by Charles E. Brooks in his comprehensive history of the Madison, The Living River (SI, April 21). That it may not be the absolute best trout stream does not matter; it is the reputation that counts. The Madison is to the average fly-fisherman as the Matterhorn is to the mountain climber, or Kenya to the big-game hunter. There may be rivers with larger trout, or taller mountains, and big-game hunting is not allowed in Kenya today, but each is a symbol of its sport. The Madison represents the best of everything to trout fishermen: big fish, clear water, distance-hazed blue mountains and a chance to wade in the footsteps of famous fishermen.

Like a number of rivers in the West, however, the Madison—the lower half, at least—along with its salmonflies, is being threatened by a dam. But this dam, unlike many that menace rivers today, has been around since 1906. That's when a hay meadow bordering the Madison just downstream of the ranching town of Ennis was flooded to form Ennis Lake, commonly called Meadow Lake. As a result of this reservoir, the trophy brown and rainbow trout of the lower river, which used to average larger than those of the upper river, have "shrunk." and that doesn't make a fisherman who's traveled thousands of miles to catch a legend very happy.

Meadow Lake was only about 30 feet deep at its deepest point. With the inevitable siltation that occurs in all reservoirs, it became shallower still. Moreover, the Yellowstone earthquake of 1959 dumped half a mountain into the upper river, accelerating the siltation. The lake's maximum depth is now 16 feet, the average depth a mere nine. In the sunny days of late summer the three-mile-wide reservoir becomes a huge solar collector. Water from the upper river takes an average of 10 to 12 days to move through the lake, and by the time it flows through the turbines of the Madison dam and enters Beartrap Canyon to begin its journey to the Missouri 35 miles downstream it is as much as 10° warmer than when it came into the reservoir.

It is this warmed water that is "shrinking" the fish in the lower river. Trout grow best in water with a temperature of about 60°; when it's below 45° or above 70° they hardly grow at all. Temperatures in the lower Madison have been as high as 80° in late summer, and the average is near 70°. In July and August the lower river's fish are caught in a sort of metabolic holding pattern; they don't actually shrink, but a four-year-old fish from the lower river is only 16 inches long, compared with 18 on the upper river. Eight-year-old fish, those four-pound-and-up trophies for which the Madison is famous, are four inches shorter and a pound or two lighter in the lower river. In addition, late-summer fish are noticeably soft-fleshed and taste like the algae that has thickened on the river's rocks, another consequence of the warmer water.

The salmonflies are also smaller in the lower river, and the famed hatch has ceased to exist for three to four miles below the dam. Such "popular" warm-water fish as yellow perch and carp have been showing up in the changed habitat of the river, too. It is this altered habitat that poses the real threat to the stream, not trout mortality, though that may occur as the reservoir continues to silt in.

The more impatient trout fishermen suggest dynamiting the dam, thereby allowing the river to run freely again, which, naturally, upsets the Montana Power Company, the owner of the dam. While the dam generates less than 1% of the company's total electrical output, it long ago paid for itself, and Montana Power is understandably opposed to its destruction. The standoff is a common one in the West today, where the skirmishes between energy and environmental/recreational groups have replaced U.S. Cavalry vs. Indians as the standard confrontation.

Happily, the two sides in the Madison conflict are not committed to unrelenting non-compromise in the manner of Custer and Crazy Horse. Part of the reason may be that Montana Power, like many power companies these days, isn't the most popular institution in a state where cold winters often make monthly home-heating bills as hefty as the mortgage payment. The company is eager to enhance its public image, and there is no better way to do so than by helping to solve the problems of the Madison. This is no mere public-relations gesture, either, because localities depend on visiting fishermen and the big bucks they spend to catch big trout.

As a result, Montana Power, the Montana Fish, Wildlife & Parks Department and Trout Unlimited, among others, are trying to arrive at a reasonable solution to the Madison problem, short of blowing the dam down the Bear-trap or allowing the river to become a celebrated yellow perch fishery. Not that there aren't some lingering disagreements. Montana Power, for instance, won't concede that the reservoir is the only significant heat source on the river, in spite of infra-red aerial photos recently taken of the whole river to locate hot springs or other phenomena possibly contributing to the problem—photos that showed the reservoir was the problem. But that is corporate public-image procedure; don't concede anything you don't have to. Otherwise, as officials of the Fish, Wildlife & Parks Department and Trout Unlimited have stated, Montana Power has been "very cooperative."

Studies are under way to determine just what can be done to prevent heat buildup in the reservoir. These alternatives are being considered: dredging the lake to make it deeper (which would be very expensive), diking the lake to allow the water in the main channel to move more quickly (also expensive, and esthetically questionable), and either raising or lowering the level of the lake. Raising the level would merely delay the solution of the problem for a few years, and perhaps drown the town of Ennis. Lowering the level appears to be the more reasonable approach. That would substantially reduce its surface area and hence its heat absorption, and allow the water to move more swiftly, while only slightly decreasing the generating capacity of the dam. A four-foot lowering, for example, would reduce the surface area 60%. Water would pass through the lake in three days instead of almost two weeks. Generating capacity would be reduced 10% to 15%.

Naturally, because both a corporation and a state agency are involved, the solution will not come quickly. Studies must be completed, decisions made, and perhaps a bit of corporate inertia overcome. A computer model has been made of the reservoir, using data from average, cool and warm years, to try to predict just what will happen if the reservoir is raised, lowered, diked or removed. Nothing will actually be done until at least 1981. When something is done, all trout fishermen will pray that the lower Madison will run cool in late summer once again, that algae will cease to choke the river, that the salmonflies will hatch below the dam and that the trout will start to grow to former size.