• 
• Japanese
• 
• IETC's Focal Area
• Waste Management
• Publications & Tools
• Meetings & Workshops
• Global Partnership on Waste Management
• Background
• Objectives
  & Expected Outcomes
• Framework
• Sub-focal Areas
• Information Platform
• Meetings
• Participation / Membership
• Water and Sanitation
• Publications & Tools
• Meetings & Workshops
• Resources
• Publications & Tools
• About IETC
• Background and History
• Director
• Activity Reports
• Supporting Foundations
• Internship
• Contact Us

Lessons Learned from Lake Chivero

Watershed dynamics

The changes in the watershed of Lake Chivero showed that watersheds can change rapidly. Population increases, increased livestock on communal lands, urban drift led to rapidly expanding urban populations, and intensified urban cultivation due to increasing urban poverty all added to nutrient loads in the lake. With all the best intentions, traditionally trained sanitary engineers were not adequately equipped to deal with rapidly changing environmental issues. Lake models generally assume a semi-equilibrium state, i.e., a more or less fixed nutrient loading as a base line. However, this case study shows that nutrient loading rates can change rapidly, and water quality managers should be able to respond accordingly.

Multiple nutrient sources

Sanitary engineers design operational wastewater treatment works to cope with expected deliveries from the sewage transport system. They assume that the most important source of nutrients to receiving waters is the sewage reticulation, and that if sewage is adequately treated, eutrophication problems would not occur. As a result, the Harare Municipality invested heavily in sophisticated sewage treatment works. However, the Lake Chivero case shows that nutrients can arise from multiple sources, such as communal land farms, inadequately serviced peri-urban areas, street runoff and badly sited waste dumps. Water quality managers in developing countries must be alert and imaginative to deal with multiple causes of eutrophication.

Public involvement

The Lake Chivero case also shows that the typical public servant tends to be a lone bureaucrat quietly working on his assignments, and thus missing the potential power of public participation. The majority of Harare dwellers are unaware of the problems faced by the Municipality to provide them with clean water, and are therefore not conditioned to taking remedial measures themselves. However, for a eutrophication management strategy to be effective, there must be participatory governance.

Table of Contents

• Brochure
• 
• 



• International Year of Forests
• 
• 



• World Environment Day
• 
• 



• UNEP Campaign
• 
•