• 
• Japanese
• 
• IETC's Focal Area
• Waste Management
• Publications & Tools
• Meetings & Workshops
• Global Partnership on Waste Management
• Water and Sanitation
• Publications & Tools
• Meetings & Workshops
• Resources
• Publications & Tools
• About IETC
• Background and History
• Director
• Activity Reports
• Supporting Foundations
• Contact Us

CHAPTER 7. MANAGEMENT

7.1. Introduction

Freshwater resources of the globe, though renewable, are nevertheless finite and are also threatened by pollution from industrial, domestic, and agricultural wastes and emissions. These emissions lead to eutrophication, acidification, and other freshwater transformations, which compromise their quality and capacity to support aquatic freshwater ecosystems. It is now possible, but very rare, to draw water at source for direct human consumption without treatment. An adequate water supply of acceptable standard remains the cornerstone of sustainable development, and indeed life on earth. As the human enterprise in technological development progresses and becomes global it becomes necessary to manage the planet's water resources, and the hydrological components of water storage, particularly lakes and reservoirs for their optimal use while maintaining an ecological balance. This chapter discusses the state of lakes and reservoir management globally by examining various management arrangements at local and national, as well as international, levels using selected cases as examples. In this way it illustrates management issues pertinent to given circumstances and how such issues are historically dynamic. Consequently, there is a need for management strategies to be adaptable to evolving management environments. The varying formats and development stages of institutional and legal instruments of lakes and reservoir management are illustrated, while issues, which need international resolution are pointed out. The issue of displaced persons in reservoir projects is briefly discussed with respect to equity in the long-term benefits participation. Changes in the world's climate, which need to be considered in planning and management of lakes and reservoirs, are also outlined.

The knowledge accumulated by limnologists on the hydroecological behaviour of water reservoirs and the first attempts to control their water quality testify that the success in solution of the task of the management of eutrophication depends first of all on the theoretical background concept and the reliability of the selected management strategies. It is also indispensable to consider the individual features of each water reservoir and its ecosystem. There cannot be general strategies, which would be common for even similar reservoirs situated in similar natural and social settings. The biological and hydrological regimes of each and any reservoir are individual because they are determined by a multitude of natural and technological factors.

It is commonly accepted that the degree of eutrophication of water bodies depends, to a great extent, on the concentration of nutrients in water, particularly phosphorus. The calculations show that due to the population growth and the increasing urbanization, the world input of phosphorus from the sanitation systems into the river networks will have reached 2.56 million [metric] tons per year by the end of the 20^th century. The non-point sources provide approximately an additional 0.6 million tons, mainly due to agricultural and livestock farming. As a result, the world river transport of total phosphorus (TP) has increased by no less than four times. This is the main reason for the progressing eutrophication of rivers, lakes, water reservoirs, and coastal marine waters.

The increase in the phosphorus load to water ecosystems is no longer compensated by the phosphorus holding capacity of lakes and reservoirs. Globally, these water bodies accumulate no less than 0.63 million tons of TP a year due to the physical, physico-chemical, and biochemical processes leading to the transformation of the water masses with the subsequent accumulation of the nutrients in the bottom sediments. For example, during the last 50 years, the urban population of the Volga River watershed has increased about three times, and the increase of nutrient load was of a similar proportion. In spite of the increased load, the transport of TP into the Volga's delta has grown by no more than 5%. This is due to the enormous purification capacity of the water reservoirs in the watershed, which absorb, process, and precipitate about 75% of the phosphorus transported by the sanitation systems into the reservoirs. Simultaneously, the reservoir's ecosystem precipitates heavy metals and many other harmful substances.

Observations on those parts of water reservoirs, which have a considerable input of effluents, demonstrate that the biological processes play the leading role in the self-purification of water. Near the points of effluent discharge, at the City of Tver at the Ivankovo Reservoir and at the City of Cherepovets at the Rybinsk Reservoir, the condition of the plankton community has been investigated. A zone of toxification is situated next to the effluent points while a zone, a few times larger, of eutrophication surrounds it. In the toxification zone, the mineral nutrient is regenerated from the decaying organic compounds. In the eutrophication zone, the intensity of the phytoplankton's photosynthesis is twice as much as it is in the clean parts of the reservoir. In the latter zone, the zooplankton's quantity and the species diversity increase, the biological sedimentation is intensified, as well as the co-precipitation with the detritus and pellets of phosphorus and other pollutants. It is in the eutrophication zone where the self-purification of water is completed and the concentration of the man-made pollutants comes down to the background levels.

Therefore, the eutrophication of an aquatic ecosystem should be considered as the system's reaction to its pollution. The eutrophication control strategy should not be considered as a struggle against this phenomenon, which is seen by many as environmentally harmful. The strategy should pursue an optimization of the production-and-destruction processes in the reservoir's ecosystem in such a way that the water organisms consume the solar and chemical energy in the most efficient way for the purification of water from man-made pollutants. The water reservoirs in a river system should be considered as a tool for controlling not only the quantity of water, but also its quality.

The construction of large reservoirs in Africa and South America started in the middle of the 20^th century. The first largest reservoir, Lake Kariba, was constructed between 1955 and 1958. The construction of the West African Lakes (i.e., Upper Volta, Kainji, and the massive Aswan Dam) followed soon after. These were landmarks in the economic development of Africa. From the African continent, large impoundment construction spread to other continents (Table 7.1.). It is estimated that worldwide there are 40,000 large dams, 300,000 medium dams, and 800,000 small dams. The proliferation of man-made dams and the environmental concerns attendant to them, as well as the increasing pressure on natural lakes and reservoirs by human utilisation and modification, has given rise to international concerns about the sustainable use of the earth's freshwater resources. The development of water resources for human benefit can create significant environmental and social conflicts whose resolution call for skilled management on behalf of the water resources managers and developers.

(continued)

Table of Contents

• Brochure
• 
• 



• International Year of Forests
• 
• 



• World Environment Day
• 
• 



• UNEP Campaign
• 
•