Curing the Incurable?

Douglas W Larson. American Scientist. Volume 84, Issue 1. January 1996.

Americans, it seems, have an abiding faith in the power of science and technology to remedy environmental degradation. Take, for example, the nation’s war on lake eutrophication. This federally funded effort sprang from the belief that a massive lake-restoration program could erase the damage inflicted on the nation’s lakes by decades of abuse and mismanagement. Many millions of dollars and many years later, it appears that this faith was sadly misplaced.

More than 20 years ago, in American Scientist’s Marginalia department (May-June 1973), Yale University professor G. Evelyn Hutchinson expounded on the subject of lake eutrophication, the process by which lakes deteriorate as they become increasingly productive with age. Referring to eutrophication as a “contemporary practical problem,” Hutchinson explained how all lakes evolve naturally in a manner corresponding to ecological succession. Newborn lakes are typically oligotrophic—deep, clean and unproductive. As lakes mature, however, they become more eutrophic. A eutrophic lake is typically shallow—the result of long-term sedimentation—and infested with aquatic vegetation, including rooted plants and phytoplankton.

People accelerate eutrophication by polluting lakes with sewage, fertilizers and other materials enriched with nitrogen and phosphorus, which stimulate excessive vegetative growth. Deforestation, road construction, real-estate development, agriculture and other cultural disturbances in watersheds are major sources of sediment. Thus eutrophication can proceed at a natural rate or be culturally accelerated; either way the process is more or less continuous and irreversible. Bogs, swamps and marshes—the climax stage of eutrophication—a often sites of former lakes that are nearly extinct.

Ironically, just as Professor Hutchinson, the world’s most renowned limnologist, was informing the scientific community and others about the inevitable nature of lake eutrophication, the U.S. Environmental Protection Agency was embarking on an ambitious project to halt eutrophication and restore highly eutrophic lakes to pristine conditions. The Clean Lakes Program, authorized under the Clean Water Act of 1972, proceeded to fund lake-restoration projects in 1976. By 1993, EPA had awarded grants totaling about $150 million and had spent hundreds of millions of additional dollars administering the program. Thousands of first-rate scientists and engineers participated in countless limnological studies and lake-cleanup efforts nationwide.

Congressional funding for the program was slashed almost to zero in fiscal year 1995, and the future of Clean Lakes along with other EPA programs is in doubt in the current political climate. Many, many lakes are in urgent need of help. But perhaps not the sort of help that came from the Clean Lakes Program. Unfortunately, this heroic effort may have cost us the opportunity to protect and improve lakes that can be saved.

The Clean Lakes Effort

The Clean Lakes Program had one characteristic that made it widely popular but, hindsight suggests, scientifically unsound: It targeted lakes that were highly eutrophic, ones popularly referred to as “dead” or “dying.” EPA’s promotional material led the public to believe that technical means were readily available to restore eutrophic lakes to pristine bodies of water, promptly and cheaply. This impression took hold in the minds of lakeside residents who desperately wanted their polluted lakes to be clean again. But the can-do notion that science and technology could actually resuscitate aging, weed-clogged lakes, restoring them to near-original conditions, was remarkably naive on the part of some people and simply arrogant on the part of others. What the public needed was an upfront education about the inevitability of lake eutrophication and the improbability of actually reversing the process. They would have benefited, too, from a dose of healthy skepticism about the promise of a technical solution.

Although there are examples of lakes “saved” by the program, there are many more examples d failed Clean Lakes projects. Consider the Pacific Northwest, where I work. In Oregon, despite objections from many scientists, EPA and the Oregon Department of Environmental Quality (DEQ) funded a $1 million project to eradicate weeds in Devils Lake, a popular and heavily developed eutrophic lake on the northern Oregon coast. Some 30,000 weed-eating carp, Ctenopharyngodon idella, were introduced into the lake to consume a troublesome weed, Eurasian watermilfoil (Myriophyllum spicatum but their liquefied fecal wastes fueled new crops of weeds and algal blooms that were unprecedented for the lake. Six years into the project, in 1992, investigators reported that the carp “have not significantly reduced the total amount of attached aquatic vegetation” and that only 4,000 carp had survived. Meanwhile, little was done to protect the lake’s once-pristine watershed from intensive real-estate development, clear-cut logging and myriad recreational activities, all of which contribute to the lake’s polluted, eutrophic condition.

On Sauvie Island, located in the Columbia River near Portland, EPA and DEQ spent another $1 million trying to flush sediments from Sturgeon Lake, an extremely shallow and turbid lake periodically covered by tens of thousands of migratory waterfowl. The lake is so turbid that sunlight hardly penetrates the water column, a condition that inhibits photosynthesis and hence vegetative growth, despite the enormous nutrient loadings from bird droppings and agricultural runoff. Water for sediment flushing was diverted from the Columbia River by reopening a sand-obstructed stream channel that once connected the river to the lake. The project eventually failed, however, because the diversion channel soon refilled with sediment from the Columbia River and from stream-bank erosion. Although there is little or no scientific evidence demonstrating the effectiveness of the flushing process, EPA and DEQ are seeking an additional $400,000 to reopen the channel so that it can resume.

EPA even studied the feasibility of restoring ancient Upper Klamath Lake, a 250-square-kilometer relict of the western Great Basin in southern Oregon. The algae in Upper Klamath Lake are so abundant that huge rafts of this planktonic vegetation are easily visible in infrared photographs taken at 80,000 feet by U-2 aircraft. The study, costing $100,000, considered various restoration techniques, including the use of a dredge to deepen the lake. EPA’s proposed technique would have cost up to $2.6 million; a more ambitious proposal from the U.S. Army Corps of Engineers would have cost up to $150 million. In 1983, EPA wisely shelved the Upper Klamath Lake restoration plan, ending what would have been a gigantic pork-barrel project.

EPA and local governments did spend nearly $20 million during the early 1980s dredging and flushing Vancouver Lake by diverting water from the Columbia River through a newly excavated channel. This was the most expensive Clean Lakes project ever undertaken. Dredging removed approximately 6.5 million cubic meters of sediment, half of which was deposited near the center of the lake to create an island roughly 1 kilometer in diameter. But lake improvements were merely temporary. Since 1983, when the project was completed, the lake has become shallow again as sediments continue to pour in from many urban and agricultural sources in the watershed. The artificial island and the inshore sediment-disposal sites, constantly battered and thus eroded by wind-driven waves and currents, also yield sediments that are redeposited throughout the lake. Lake water quality is no better now than it was prior to “restoration.”

The same lesson can be learned from positive examples. Perhaps the most celebrated example of lake eutrophication and recovery is Seattle’s Lake Washington. After decades of using the lake as a sewage repository, the community finally halted the lake’s deterioration by diverting the sewage into Puget Sound. Recovery was possible for two reasons: First, the lake—being steep-sided and volumetrically large (roughly 65 meters deep and 90 square kilometers in area)—had not yet filled with weeds and sediment; and second, corrective action was taken before the lake had become a shallow, highly eutrophic body, sufficiently deteriorated to qualify for a Clean Lakes grant.

Lakes for the Future

Unquestionably, the goal of protecting and restoring America’s lakes is well-intentioned and noble. As Henry David Thoreau pointed out, “Nothing so fair, so pure, and at the same time so large, as a lake, perchance, lies on the surface of the earth.” Inspired by Thoreau’s observation, I have spent over 30 years as a limnologist studying lakes and campaigning doggedly to protect them. But experience, and the scientific evidence that has come partly from the Clean Lakes experience, has taught me to prefer a triage approach: disregarding lakes that are “dead” or “dying” and focusing on the ones that are still pristine and savable.

One example of such a lake lies in the same region as the lakes described above. In 1972, K. W. Malueg and other limnologists described Oregon’s incomparable Waldo Lake as possibly the most oligotrophic large lake in the world, stating: “Lakes of the quality and character of Waldo are rare … It represents a unique and fragile resource requiring specialized management techniques for its preservation.” They urged that the lake be monitored so that “symptoms of incipient eutrophication may be detected as early as possible.” But because Waldo Lake and other pristine lakes in the Pacific Northwest are not “problem” lakes—they are still clean and oligotrophic—they have been rejected for Clean Lakes funding. Funding priorities thus have ignored the fact that these extraordinary lakes are culturally threatened and prone to change. Recent limnological data suggest that Waldo Lake has shifted to a higher trophic status over the past 25 years, possibly in response to human encroachment. Indeed, according to the U.S. Forest Service, the number of people visiting Waldo Lake increased from 18,700 in 1971 to 173,000 in 1994. This usage increase foreshadows the lake’s degradation, which is inevitable over the very long term. But if degradation is detected early and promptly remediated, this lake and other oligotrophic lakes could be preserved for many human generations to come.

Preserving oligotrophic lakes was apparently a low-priority goal in the Clean Lakes Program. Instead, millions of dollars were squandered on weed-choked, shallow-water quagmires. Anyone cruising the muddy waters of Vancouver Lake, wondering whether the $20 million spent restoring the lake was a wise investment, would be well advised to watch out for barely submerged mudflats and rusted strands of barbed wire.