Worldwatch Paper #128: Imperiled Waters, Impoverished Future: The Decline of Freshwater Ecosystems
Janet N. Abromovitz
A new Worldwatch Paper, Imperiled Waters, Impoverished Future: The Decline of Freshwater Ecosystems, demonstrates that giant dams, massive irrigation systems, and widespread logging often bring few economic benefits, and instead cause environmental degradation, poverty, and suffering, as well as irreplaceable loss of biodiversity.
Billions of dollars spent for flood control, plus the effects of land degradation, actually increased the severity and cost of flooding on the Columbia, Rhine, and Mississippi rivers.
Pollution and diversion have driven freshwater fisheries into collapse worldwide, and the extinction of freshwater species far outpaces the extinction of mammals and birds.
Wetlands worth billions of dollars to the public for fisheries, water purification, and groundwater renewal have been converted to less beneficial uses.
Freshwater ecosystems are both disproportionally rich and disproportionally imperiled. Some 20% of 9,000 known freshwater fish species worldwide are already extinct or imperiled, with the toll much higher where human impact is heavy. In North America and Europe, about 40% of all native fish species are extinct or imperiled. In East Africa's heavily stressed Lake Victoria, 40% of its unique 350 native fish species are at risk, with 60% already extinct.
Senior researcher Janet N. Abramovitz, author of the report, said, "As alarming as these numbers are, the rate of extinction is even more alarming -- a hundred to a thousand times the natural rate. By destroying species faster than nature can create new ones we are running a 'biodiversity deficit' that can never be recovered." She added, "If these losses had occurred overnight they would have made headlines worldwide, and the full weight of government and business would be brought to bear to save freshwater fish species and fisheries. It is tragic that these slow catastrophic changes are accepted as the 'price of progress,' because it is a price we must not -- and need not -- pay."
Beyond their obvious benefits for agriculture and industry, intact freshwater ecosystems are vital to human health and economies worldwide. They provide clean drinking water, natural flood control, as well as income and food from fisheries. But the human desire for immediate profit and 'quick fixes' has led to a cascade of damage. Hydroelectric dams, water diversions for agriculture, flood control levees, dredging, air and water pollution, habitat degradation such as logging, as well as exotic species such as the zebra mussel, are combining to disrupt and destroy freshwater species and functioning ecosystems worldwide. In one tragic example, when a dam was built on the Mun River in Thailand, more than two thousand families were evicted from their homes, thousands more lost their source of food and income, and all 150 species of fish disappeared from the river.
Since 1900, about 33 of 330 native mussels species in North America have become extinct, 199 of the remainder are at risk -- a great global loss, as North America is home to fully 1/3 of all freshwater mussel species. Only about 75 species are considered stable by biologists.
Some 50 native species of freshwater mussels once inhabited the Little Tennessee River, but after a dam impounded the river in 1979, 44 species disappeared.
At one city on the German/French border, the Rhine River's floodwaters had risen 7.62 meters above flood level only four times this century before 1977, an average of once every twenty years. Since then, that level had been breached ten times, an average of once every other year.
Based on successes around the world, and the results of many regional and economic studies worldwide, the report recommends basic changes in policy: recognize that the values that intact ecosystems provide before short-term decisions cause long-term losses; and that governments, lenders, and businesses recognize that many development projects, however glamorous they may seem, can actually reduce economic benefits. Here are several examples:
The value of water in one Nigerian floodplain was calculated at $45 per 1,000 cubic meters if left alone to support local fisheries, farming, and livestock. But if diverted for other uses -- at high cost -- its value drops to just 4 cents per 1,000 cubic meters.
One 552,000-acre swamp in Florida provides $25 million a year in water storage and aquifer recharging, with no upkeep costs.
The value of intact mangrove swamps in Malaysia for flood control and storm protection alone has been estimated by economists at $300,000 per kilometer, the cost of rock walls that are needed to replace them when they are cut down. If the value of fisheries is included, the figure would be even higher.
Economic studies of the Missouri River show that recreation produces, at very little cost, at least four times the revenue of river barge traffic, which requires costly and repeated dredging and channelization. Ending the public subsidies for navigation would also help restore the river's natural functions such as controlling floods and nurturing fisheries.
Yet despite the clear dollars-and-sense relationship shown by the studies above and many others, governments, engineers, and investors are entering into devil's bargains of mega-projects that will enrich a few in the short-term, but impoverish many in the long term. Poorly planned development that "kills the goose that lays the golden egg" continues. Logging, dams, flood control, and massive land conversion wind up costing more than they are worth, while destroying forever biological diversity that provides direct food and free services for humans.
In 1895, the Columbia River in the Pacific Northwest provided a bounty of nearly 20,000 tons of salmon a year. One hundred years later, the catch had collapsed to just 533 tons. Projected for the next century, that is a loss of nearly 2 billion tons of salmon missing from the local economy and world food supply.
The Great Midwest Flood of 1993 rendered ineffective more than a thousand levees along more than 6,000 miles of the river. The cost of that flood exceeded $12 billion.
In the Mekong River in southeast Asia, the benefits of maintaining the natural flow of the river would allow 52 million people in Laos, Cambodia and Vietnam to continue supporting themselves with little capital investment. An expensive plan to dam and divert the river -- a staircase of dams that would reduce the flow of the Mekong by 50% and provide electricity and water for Thailand's booming economy -- would push the region's people further into poverty and saddle them with a burden of debt to pay for the dams.
The report describes examples that show great improvements can be made in managing natural resources to avoid losses like the above. Better sewage treatment and changes in industrial processes have reduced the amount of heavy metals entering the Rhine River by 90% since the 1970s. In the Pacific Northwest, a shift is beginning towards non-damaging economic uses of natural resources (such as recreation and non-timber forest products) that employ more people and provide a more sustainable economic base than current destructive uses.
Yet Abramovitz cautions that without changes in national and international policies, and greater cooperation, the decline is likely to continue. The key to stopping this needless destruction and repairing damage already done requires abandoning the fragmented approach to managing rivers and their watersheds. Rather than having dozens of agencies and bureaucracies, each managing a piece or a function of a river within a narrow mandate, the author recommends integrated ecosystem-based planning at the watershed, national, and international levels. She recommends managing resources over large enough areas and long enough time scales to allow their species and ecological processes to remain intact while still allowing human activity.
The cost of restoring the natural flows to rivers would not be nearly as costly and disruptive as many would have us believe. Restoring half the wetlands in the lower 48 states to their natural functions would affect just 3% of the nation's agricultural, forest, or urban land. Removing two aging dams on the Elwha River in Washington State would cost only $100 million, but would yield $3 to $6 billion per year in benefits, including fishing and other recreation, from restoring the river and its wild salmon -- a substantial return on investment.
We already know the heavy price that regulated rivers, dam construction, water diversion and pollution, alien species, fisheries mismanagement, and habitat degradation and fragmentation can exact from a region. The time has come to act on a corollary principle: over the long-term, keeping naturally functioning ecosystems healthy will offer the greatest number of benefits for the greatest number of people.