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Research and advocacy for the best use of Zambezi waters
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Africa: > Research and advocacy for the best use of Zambezi waters
Research and advocacy for sustainable Zambezi management
In recent years, scientists have undertaken significant research to prepare the groundwork for evaluating resource management and environmental flow needs in the Lower Zambezi Valley and Delta. ICF’s Dr. Richard Beilfuss conducted the fundamental hydrological studies in cooperation with the Department of Water Affairs in Mozambique, analyzing long-term changes in regional runoff patterns, flooding processes, and water balance components for the lower Zambezi. The study built on previous hydrological studies by Department of Water Affairs staff, Rendel Palmer and Tritton, the Swedish Consultancy, Dr. Peter Bolton, Dr. Jan Sushka and Dr. Policarpo Napica, Dr. Bryan Davies, and others, reviewing the sources and quality of data available for modeling flow requirements. Beilfuss and Carlos Bento assessed key indicators of hydrological alteration that relate changes in the magnitude, timing, duration, and frequency of river flows to important social and ecological processes in the delta.
Several studies have linked the Zambezi flooding regime with important economic and socio-cultural benefits. Dr. Tor Gammelsrod and Dr. Antonio Hoguane studied the effect of Zambezi River management on the prawn fishery of central Mozambique, establishing that shrimp abundance is directly related to Zambezi runoff patterns and that past Cahora Bassa operation has resulted in a loss of $10-20 million per annum. Dr. Jose Negrão examined one hundred years of change in the Zambezi Delta subsistence economy, while Dr. Jane Turpie and colleagues estimated the current economic value of subsistence farming and fishing activities in the Zambezi Delta. Dr. Jeremy Anderson, and Baldeu Chande, and Paul Dutton projected a substantial economic return, in terms of trophy hunting and meat production, on restoring healthy populations of Cape buffalo and other game species that were decimated by illegal hunting on the dry floodplain grasslands below the dam. During 2000 and 2001, Dr. Arlindo Chilundo, Dr. Wapu Mulwafu, and Dr. Allen Isaacmen, and their students collected more than 750 hours of oral history interviews in a sample of communities between Cahora Bassa reservoir and the Zambezi Delta. The oral histories describe the economic and cultural importance of the pre-dam flood for the people of the Zambezi, and compare these findings with the current production and social systems of those communities.
Other studies have examined the implications of flow management for Zambezi basin biodiversity. Ecological research by Beilfuss and colleagues compared the historical distribution of vegetation communities of the Zambezi Delta with the current distribution and assessed patterns of change, including woody species invasion into floodplain grasslands, displacement of flood-tolerant species by more upland species, terrestrialization of floodplain water bodies, displacement of freshwater vegetation by salt-tolerant species, and degradation of coastal mangrove. Bento analyzed the link between Zambezi flooding patterns and the breeding and feeding ecology of endangered Wattled Cranes, an umbrella species for biodiversity conservation in the lower Zambezi.
The first phase of the IUCN Zambezi Basin Wetlands Conservation and Sustainable Utilization Project (from 1996-2000) promoted the wise use of natural resources in the wetlands of the Zambezi Basin, including the Zambezi Delta. A series of IUCN reports describe current land use patterns in the Zambezi Delta. The project focused on two community-based natural resource management schemes, one for palm wine production in Borassus palm savanna and one for sustainable use of each of the nine species of mangrove in the Marromeu Complex.
A series of aerial surveys were conducted to establish baseline numbers and trends in the population of large mammals in the Marromeu Complex over the past 35 years by Dr. Ken Tinley, Dutton, Roberto Zolho, and others. These surveys enable the quantitative evaluation of changes in wildlife populations and distribution following the implementation of the management plan. Intensive waterbird surveys were conducted during the period 1995-2000 by Beilfuss, Bento, David Allen, and others.
Most recently, Beilfuss simulated the capacity for different flood releases from Cahora Bassa Dam using the U.S. Army Corps of Engineers HEC-5 reservoir routing model for the entire Zambezi catchment. Using an historical 92-year flow series accepted by the SADCC Hydroelectric Hydrological Assistance Project and Unidade Tecnica de Implentacao de Projectos Hidroelectricos-Mozambique, he modeled the potential to generate short-duration, high-volume flood release of different magnitude, timing, and duration from Cahora Bassa Dam. Each flood release is analyzed in terms of its effect on hydropower generation, including firm power reliability and total energy output. The study demonstrates that a variety of options are available for generating meaningful flood pulses during the normal flood season months of January, February, or March, without a significant reduction in hydropower output.
We disseminated research findings through a series of face-to-face meetings, including three international workshops and numerous public forums and private presenatations to the stakeholders, decision-makers, and the general public. The first international meeting, the Workshop on the Sustainable Use of Cahora Bassa Dam and the Zambezi Valley (October 1997) was hosted by the dam managers and attended by three national ministers, two governors, and other prominent decision-makers. During this meeting, participants reached consensus on an ecologically sustainable framework for managing the water resources of the lower Zambezi and improving the living standards of thousands of riverine households. The second international meeting (March 2001) outlined the ways forward for gathering the necessary social and ecological data needed to improve the management of the Zambezi, and provided detailed training for staff of the Zambezi Valley Development Authority and the University of Eduardo Mondlane towards conducting this research. The third meeting (July 2002) engaged lower Zambezi stakeholders, dam operators, policy makers, and NGOs in developing a common vision for the future of the Zambezi Valley. This work has featured in journals, radio and television programs, and newspapers in Mozambique and abroad. This extensive dialogue has resulted in the political will and commitment necessary to to implement a vision for future of the Zambezi Valley and Delta.
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