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WASTEWATER LAKES: BIODIVERSITY
ASSET OR LIABILITY?

by Milton Friend

Executive Director
Salton Sea Science Subcommittee

Presented at North American Lake Management Society Symposium,
Reno, Nevada, December 1-4, 1999.

Introduction

The Symposium theme, "Water: 21st Century Gold", is a contemporary issue involving more than the human population. While attending a recent meeting in London, England, I read a feature article appearing in The Daily Telegraph that began by stating:

"IT IS too late to stop the first stages of global warming, the destruction of thousands of the world’s species or prevent shortages of water across swaths of Africa and Asia that could provoke wars over the next 25 years, the UN claimed yesterday."

That article went on to note that the Global Environment Outlook Report, GEO 2000, stated that "full-scale emergencies" exist as a result of water shortages and that over the next 25 years the world would begin to run out of fresh water and "water wars" could spread across a wide belt of North Africa, the Middle East and Asia. Reality is that human use of fresh water will always take precedence over providing water for wildlife. Therefore, the survival of many species that comprise the higher life forms of our planet’s biodiversity will continue to be severely challenged under current conditions and projected additional withdrawal of fresh water for human use. Wildlife are at the "end of the pipeline" in having access to fresh water and it is unrealistic to assume a change in priorities as human populations continue to expand and draw upon our finite amounts of fresh water. Practicality demands that we make better use of our water if we are to preserve biodiversity, and ultimately ourselves. This must include reusing water to whatever extent is feasible.

Water is a substance more precious than oil and gold. Oil and gold are associated with wealth and power but there are alternatives for both substances to meet those human desires. However, water is a basis for life for which there is no alternative. Nevertheless, water is often discarded after initial use. Much of that "wastewater" is deposited in various types of collection basins. Wildlife are often highly dependent upon these waterbodies, but all too often the consequence is death from various disease problems. Thus a dilemma exists. Without inland surface waters, many species of wildlife cannot survive. However, surface waters that are comprised of discarded water often become death traps for the wildlife that use them because they are seldom managed for wildlife well-being. The Salton Sea Restoration Project is a major undertaking that attempts to address this issue. The purpose for my presentation is to use the Salton Sea as an example of a major effort to reuse water for the benefit of wildlife and, therefore, society in general.

Avian Biodiversity of the Salton Sea

To place the Salton Sea in perspective as a habitat for birds, it is necessary to consider landscape changes that have occurred in North America and, specifically in California, along with the life cycle needs for the species that are found at this waterbody. Many avian species are migratory, annually moving long distances from their breeding grounds to their wintering grounds and then return to those breeding areas. A large segment of these migrants are dependent upon inland wetlands. California leads the nation in loss of wetlands. More than 90 percent of the wetland acreage within California present at the time of colonization of the United States has been converted to other forms of landscape, primarily agriculture and urban development. This presents a major problem. The abundance of breeding habitat in northern areas of the Pacific Flyway, such as Alaska, provides for the production of large numbers of migratory birds which are then dependent upon the availability of suitable habitat to sustain them along the Flyway. Habitat losses along the Flyway have resulted in the Salton Sea becoming critical habitat for some of these species.

More than 400 species of birds have been recorded within the Salton Sea ecosystem. People travel to this location from across the nation and from beyond our borders to seek sightings of species as diverse as pelagic frigate birds, tropical species such as flamingos, various species of shorebirds, wading birds and other waterbirds, raptors such as ospreys and peregrine falcons and land birds such as the burrowing owl. Within the western United States, only the Texas Gulf Coast has greater avian biodiversity. This incredible species richness has resulted in the development of the Salton Sea International Bird Festival, now an annual event. Bird watching annually brings several million dollars into the local communities of the Sea.

The importance of the Salton Sea for some of these species is seen by the following uses of the Sea:

In general, bird populations within the Salton Sea ecosystem on almost any given day number at least in the hundreds of thousands and at times are in the millions. However, during recent years, the birds of the Sea have been subject to an array of disease problems that continue to impose a heavy toll of bird deaths.

Avian Disease Problems

Disease, whether it occurs in humans, domestic animals or other species is an outcome, not a cause. Often, the outcome of disease is driven by environmental factors that either create or facilitate conditions that result in enhanced opportunities for disease agents to flourish within susceptible host populations. Water quality is often an important dimension of the tripartite equation of host, agent and environment that is the foundation for disease.

The diversity of diseases, their frequency of occurrence and magnitude of losses at the Salton Sea is indicative of an ecosystem under severe stress. Examples include a 1992 event that killed an estimated 155,000 birds, most of which were eared grebes; a 1996 outbreak of avian botulism that killed an estimated 15-20 percent of the western population of white pelicans and more than 1,000 endangered California brown pelicans; and losses from Newcastle disease of the entire production of double crested cormorants nesting on Mullet Island during 1997 and 1998. Disease outbreaks are an annual event for birds at the Salton Sea and the pattern of disease is unlike that occurring elsewhere.

Disease events have served as a catalyst for the current focus for restoration of the Sea. The proper perspective for this project is not restoration to some pristine state of conditions. Instead, the efforts are focused on management of the Sea to achieve and sustain a desired level of environmental conditions that will facilitate achievement of agreed-upon Project goals. These goals are not focused on avian disease. Instead, they address a broader range of values that benefit wildlife and the human population of this geographic area.

The Conversion of Liability to Assets

The Salton Sea Restoration Project is an unprecedented effort for using wastewater from agriculture to sustain a large-scale waterbody in a manner that provides a healthy environment for fish and birds, as well as recreational opportunities for humans and economic development. Reused water is only an asset if it provides benefits that exceed any negative impacts resulting from the use of that water and the costs for making the water available. Negative impacts have their foundation in the additives that become constituents of the water during initial use and along the pathways to reuse. The probability for adverse impacts is a function of the environment the water reaches, the specific additives and the level of contamination. Water quality that takes life rather than sustaining it is a liability rather than an asset.

Salts and nutrients are the additives of primary concern present in the agriculture drainwater that constitutes the waters of the Sea. The partially correct, often cited statement that, "dosage alone determines toxicity," applies to salt just as it does to pesticides, heavy metals and other substances. There are finite limits at which organisms can tolerate salt intake before the salt becomes toxic and results in the death of various organisms. The salinity of the Salton Sea is 44 parts per thousand (ppt) and increasing annually at a rate of 0.5 percent. Fish will likely be the first critical component of the Sea’s food chain to be lost from salt toxicity. The loss of fish will eliminate the foodbase for fish-eating birds, a major component of the Salton Sea ecosystem. Therefore, it is essential that the salinity of the Sea be controlled and maintained within acceptable levels.

The nutrient additives make the Sea a highly eutrophic waterbody. Algal blooms are an outcome of this nutrient loading and the environmental conditions present. These blooms and their decay can result in oxygen depletion that compounds the problem of already limited amounts of dissolved oxygen in the water column. Anoxia is a major factor associated with the massive fish kills that occur at the Sea. Also, some forms of algae can produce toxins capable of killing birds and fish. The large-scale grebe mortalities at the Sea are thought to be due to algal toxins but this hypothesis remains to be proven.

It is necessary to understand nutrient loading and cycling processes at the Salton Sea before strategies can be developed for maintaining "safe levels" of nutrients needed to provide for a healthy Sea. Investigations are currently underway to gain this knowledge and guide determinations of the extent of management that may be needed.

Despite the large size of this waterbody, there is strong reason to believe that the water quality of the Salton Sea can be improved and sustained at a level that will support the goals established for the Sea. Also, it will become possible to minimize the potential for major losses from disease as the ecological basis for these diseases becomes better understood.

Discussion

Ninety-seven percent of all the water on earth is unsuitable for drinking or agriculture because it is salt water (Gleick 1993). In many parts of the world the fresh water resources are oversubscribed relative to needs vs. availability. As noted above, these deficiencies will increase. A stark perspective on this matter is offered by Gleick (1993) who stated,

" As we now look to the 21st century, several challenges face us. Foremost among them is how to satisfy the food, drinking water, sanitation, and health needs of ten or twelve or fifteen billion people, when we have failed to do so in a world of five billion."

Given this situation, how can we hope to provide adequate water to sustain global biodiversity, especially when it has been noted that a disproportionate richness of species lives in inland waters? Covich (1993) reported that 12 percent of all animal species live in inland waters compared with 7 percent in the oceans, despite the fact that the oceans comprise 70 percent of the earth’s surface and inland waters only 1 percent. Reusing water for wildlife that cannot be used by humans has become a necessity rather than an option if society is to truly address the conservation of biodiversity.

Much of our wastewater if properly managed has the potential to be "21st Century Gold" relative to its value for biota. However, we have much to learn about how to manage these waters in a manner that provides benefits rather than liabilities. Failure to do so results in the waste of a potential valuable resource and the continued deposition of waters that are "Fools Gold" results in the waste of the wildlife species that "stake claim" to those environments.

This issue is far greater than the conservation of species just for the sake of animal life. Human benefits from ensuring recreational opportunities and their attendant economic contributions are substantial returns from this investment. Further, the aesthetic and other values from our association with water environments and the wild species they support should not be underestimated as contributions to our psyche. Also, it should be remembered that extinction is forever. Currently unrecognized future contributions that some species may have for the well-being of humans are among the reasons for the conservation of global biodiversity.

The Salton Sea Restoration Project is especially relevant for the preservation of global biodiversity because agriculture drainwater is the primary source of waters reaching the Sea. Worldwide, agriculture accounts for about two-thirds of water use (Postel 1993). Regardless of what levels of water conservation take place, there will always be a large amount of water being discharged as a result of providing food for the human population. The Salton Sea presents a unique opportunity to apply, on a large scale, our ingenuity and technology in a manner that reuses water from agriculture in a secondary manner to provide an additional array of major benefits. It is time to get on with the task of demonstrating how to do so.

Conclusion

"Sustaining an adequate quality of life for the world’s people, both those now alive and the generations to come, requires matching our use of resources to our goals and desires. One of those resources, fundamental to life, is fresh water. Better understanding of the connections between water and all of our concerns will lead to better understanding of proper and successful approaches to water management." (Gleick 1993). Our goals and desires as people vary widely with our personal circumstances and are an important component of what constitutes proper and successful approaches to water management. For the most part, water concepts have been heavily focused on serving humans, preventing further degradation in the quality of our remaining fresh water resources and seeking means for conserving water use to provide for the expanding human population. These are all appropriate and needed areas for focus. However, this is not enough.

Not nearly enough attention is given to the conversion of "wastewater" into a water resource for other species. While the alchemists of the past were unable to convert "Fools Gold" to gold, current society has the ability to convert wastewater to "21st Century Gold" and, as stated earlier, water is a necessity where gold is not. It is critical that we recognize and act from the perspective that usable water is not just for people. We have moral obligations regarding our stewardship role for the other species of Planet Earth. Regardless of those obligations, reality is that, "The nation’s biological resources are the basis of much of our current prosperity and an essential part of the wealth that we will pass on to future generations" (Pulliam 1996).

From my perspective, the concept of wealth extends beyond monetary and material considerations to cultural and spiritual wellness. Aldo Leopold (1949) spoke to this matter in the first sentence of the Forward to A Sand County Almanac: "There are some that can live without wild things and some who cannot. These essays are the delights and dilemmas of one who cannot". I share that philosophy and point to the Salton Sea as a contemporary challenge relative to the conservation of wild things for their well-being, and for that of current and future generations of humans.

Prologue

Nash (1993) stated that, "Water quality remains a key indicator of a country’s ability to invest in the health of its population and its environment; it is but one of an integrated set of environment and development issues that require immediate attention." I contend that the ability to reuse water for the benefit of wildlife and humans alike is as important an issue as the focus on primary waters alluded to by Nash. Much of water reuse should involve the development and management of water impoundments created for the receipt of waters not suitable for drinking by humans or use by agriculture. These waters should be considered part of the global water resource for sustaining global biodiversity and managed accordingly rather than accepted as waste. Society can ill afford to waste any of its water resources. The preservation of global biodiversity requires that we do not.


Covich, A. P. 1993. In Waters in Crisis: A Guide to the World's Fresh Water Resources, P.H. Gleick (ed.), pp. 40-55. Oxford University Press, New York.

Gleick, P.H. (ed.) 1993. Waters in Crisis: A Guide to the World's Fresh Water Resources. Oxford University Press, New York.

Leopold, A. 1949. A sand County Almanac. Ballatine, 1991 (re-issue), New York, NY, 296 pp.

Nash, L. and P. H. Gleick. 1993. "The Colorado River Basin and Climate Change: The Sensitivity of Streamflow and Water Supply to Variations in Temperature and Precipitation." U.S. Environmental Protection Agency, EPA 230-R-93-009, Washington D.C. 121 pp

Pulliam, H. R. 1995. Sources and sinks: Empirical evidence and population consequences. In: Population Dynamics InEcological Space and Time, O.E. Rhodes, Jr., R.K. Chesser, and M. H. Smith (eds.),The University of Chicago Press, Chicago, IL.

Postel, S. 1993. Water and Agriculture. In Waters in Crisis: A Guide to the World's Fresh Water Resources, P. H. Gleick (ed.), pp. 56-66. Oxford University Press, New York.



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