'And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters. ' Genesis 1:6 Lake McIlwaine is a man-made lake. It was formed in 1952 by the Hunyani poort Dam and is situated on the Hunyani River some 37 km southwest of Salisbury* in the Republic of Zimbabwe**. It is a lake of many aspects: being a popular recreational site, the City's primary water supply reservoir (and the fourth largest impoundment in Zimbabwe), a source of irrigation water to downstream farms, an important fishery, and, until the 1970s, the receptacle of Salisbury's sewage effluent. It is, in short, typical of so many 'urban' lakes in Africa and throughout the world. Lake McIlwaine is also unique, to my knowledge: being amongst the first of the major man-made lakes on the continent to suffer from what is known as cultural eutrophication, and the first to be r:ehabilitated to a mesotrophic state through a rational programme of lake management. This volume synthesizes this process of eutrophication and recovery in terms of the geology and geography (Chapter 2), physics (Chapter 3), chemistry (Chapter 4) and biology (Chapter 5) of the lake, and, whilst discussion of the trophic relationships between these components is beyond the scope of this monograph, discusses its utilisation, conservation and management (Chapter 6). * Subsequent to writing, the name of the Zimbabwean capital was changed to Harare on 18 April 1982. - Ed.

This compilation of papers provides useful insights on the differing approaches to water quality and the diversity of strategies in water quality management worldwide. Considering the current situation and looking to the future, the aim of this publication is to provide a sensible addition to the literature by concentrating on several important aspects of water and the environment.

A synthesis of tropical freshwater systems which illustrates the basic theory of freshwater biology.

Limnology - the study of inland waters - had its genesis in Europe about the turn of the century. The studies of Fore1 on Lake Geneva were of seminal value at this time. It prospered under the early guidance of Thienemann, Naumann and Wesenberg-Lund in Europe and, soon transplanted, of Birge and Juday in North America (to name just a few early spirits). Now, liminology is a respectable scientific discipline taught at many universities, and limnologists are recognized as important contributors to our understanding of how this fragile spaceship functions. All this acknowledged, it must also be acknowledged that limnology is not yet a globally comprehensive science. To be sure, much is known about globally applicable processes, and the structural elements of aquatic ecosystems worldwide, but limnological emphases, interests and concerns remain essentially European and North American in balance. Much is known about lakes and rivers in less than one fifth of the world's land area (northern temperature regions); rather little is known about inland waters elsewhere.

Humans and animals are not the only creatures that migrate. Plants also do. This book is a comprehensive and analytical account of the migration of an Old World plant, water hyacinth (also known to botanists as Eichhornia Crassipes) from the Amazon Basin and surrounding areas to Africa through human agency from about 1800 to the present. As an integrative work, which benefits from methodologies and conceptual approaches drawn from limnology, botany, biology, geography, history, ecology and other social sciences and humanities, the book further explores the political, economic, and ecological consequences of the spread of water hyacinth from its native habitat through European botanical gardens to Africa rivers, lakes, dams, and wetlands. In part, as a narrative of Western tinkering with African ecologies gone awry, the study has strong lessons for environmental historians, and social scientists as well as contemporary foundations, aid workers, development experts and African governments. Although it may appear to be a micro-history of a single plant, water hyacinth, it illuminates broader issues in the history of the modern environment in Africa and similar studies worldwide. This study is primarily rooted on the histories of colonialism, bioinvasion, environmental realities and experiences in Africa. The highly visible pathways of hyacinth’s spread across international frontiers along watercourses and communication networks means that not only is this a trans-boundary environmental affair, but one which directly involves bilateral relations between African states.

Presents readers with an overview of lake management problems and the tools that can be applied to solve probelms. Lake management tools are presented in detail, including environmental technological methods, ecotechnological methods and the application of models to assess the best management strategy.