Newswise — Lake Naivasha, Kenya's second largest lake, is an ecosystem in crisis. The lake level has dropped by three meters from its maximum, the area has shrunk to half its size, and precious wetlands are degraded beyond recognition. At the Fourth World Water Forum, in Mexico City, Dr. David Harper of the University of Leicester presented evidence of three decades of ecological decline at Lake Naivasha and made urgent recommendations for the lake's sustainable future.

Harper contributed to a March 18 session titled "Ecosystem and Ecohydrology Approaches to Integrated Water Resources Management," coordinated by U.N. Environmental Program and UNESCO-International Hydrology Program (IHP). A member of IHP's international committee on ecohydrology, Harper's talk focused on Lake Naivasha and the Malewa Basin as one of only a dozen UNESCO "ecohydrology demonstration sites."

"Lake Naivasha was once considered one of the world's top ten sites for birds and a paradise of clear water, with beautiful papyrus and water lily fringes," said Harper, principal investigator of Earthwatch's Lakes of the Rift Valley project. "A haven for African wildlife and a major source of water for the lakeside's quickly growing population, the health of Lake Naivasha is critically important."

Harper highlighted three factors that have led to the precipitous decline of the lake. The most harmful has been the unsustainable extraction of water for agriculture and horticulture, urban and residential water supplies, and a geothermal power plant at Olkaria, leading to dropping water levels. This leads directly to the second factor: Riparian vegetation, left high and dry, is further destroyed by grazing herbivores and people looking for more arable land. Finally, more than a dozen exotic species, including the destructive Louisiana crayfish, have restructured and simplified the lake food web.

"These three factors combined mean the lake that remains has no natural buffer against the inflow of sediment and nutrients," said Harper. "The ever-smaller lake is becoming an over-enriched muddy pool, which shortly will become unusable through the development of toxic blue-green algae blooms. Its inflowing rivers, formerly sparkling and permanent, are now muddy and unpredictable."

Over the past 15 years Harper's ecological research, supported by the work of Earthwatch volunteers, has resulted in more than 50 articles in scientific journals and helped spur conservation efforts both locally and internationally. The long-term commitment of the project has been critical to understanding the true scale of ecological cycles in the lake, such as the 10-15 year cycle of destruction and regrowth caused by the introduced Lousiana crayfish.

"Without Earthwatch's support we could only have achieved a fraction of any of this," said Harper. "Most scientific support lasts for 3 years, 5 years maximum. If we had had that kind of support, we could have put a larger team of scientists into the field for that brief period only. We would have achieved some good science, at the expense of understanding neither the lake nor the country."

The Lake Naivasha Riparian Association (LNRA), a local voluntary organization formed in the 1930s, re-aligned itself in response to modern environmental concerns in the 1990s. In 1995, using the scientific results from Harper's team, LNRA successfully lobbied the Kenyan government to declare the lake as a Ramsar site, or wetland of international importance. However, management actions have not yet effectively taken hold at Lake Naivasha.

The Lake Naivasha Management Committee was legally authorized by the government to implement the Community Management Plan in 2004, but recent court challenges have inhibited their efforts. In the meantime, Lake Naivasha continues to be subjected to unsustainable extraction demands, made worse by a drought over the past two years.

"The main lesson is that the 'Tragedy of the Commons' works for water in a lake just as well as cows on a Commons," said Harper. "Each user group sees short-term benefits in money-making, or mere survival, which override any perceived long-term gain from sustainable water use."

Harper urged the support of three objectives to save Lake Naivasha from ecological collapse. First, an upper limit on basin extraction must be agreed upon and shared equitably and transparently, counteracting the dishonesty of over-use and ignorance of waste. Second, the lake wetlands and riparian vegetation in the basin must be restored to functionality. Finally, an educational campaign must be launched encouraging the principles of ecohydrology and the real value of water to all basin inhabitants.

"This is already being promoted in schools, since last year, by short, locally-made films with the message maji ni uhai, 'Water is Life' in Swahili," said Harper. The films were funded by the Vodaphone Foundation through a grant to Eartwatch (Europe) "The next step is to educate and encourage adults—all of them, from illiterate farm workers to Ph.D. horticultural experts—so that they understand the principles of wise use of water."

The World Water Forum is an initiative of the World Water Council that has the aim of raising the awareness on water issues all over the world. As the main international event on water, it seeks to enable multi-stakeholder participation and dialogue to influence water policy making at a global level, thus assuring better living standards for people all over the world and more responsible social behavior towards water issues.

Earthwatch Institute is a global volunteer organization that supports scientific field research by offering members of the public unique opportunities to work alongside leading field scientists and researchers. Earthwatch's mission is to engage people worldwide in scientific field research and education to promote the understanding and action necessary for a sustainable environment. The year 2006 marks Earthwatch's 35th anniversary.

For more information on how to volunteer on Earthwatch's Lakes of the Rift Valley project, go to