Climate change is altering hydrological processes with varying degrees in various regions of the world. This research work investigates the possible impacts of climate change on water resource and Hydropower production potential in central and southern Africa. The Congo, Zambezi and Kwanza, Shire, Kafue and Kabompo basins that lie in central and southern Africa are used as case studies. The review of climate change impact studies shows that there are few studies on impacts of climate change on hydropower production. Most of these studies were carried out in Europe and north America and very few in Asia, south America and Africa. The few studies indicate that southern Africa would experience reduction in precipitation and runoff, consequently reductions in hydropower production. There are no standard methods of assessing the resulting impacts. Two approaches were used to assess the impacts of climate change on water resources and hydropower. One approach is lumping changes on country or regional level and use the mean climate changes on mean annual flows as the basis for regional changes in hydropower production. This is done to get an overall picture of the changes on global and regional level. The second approach is a detailed assessment process in which downscaling, hydrological modelling and hydropower simulations are carried out. The possible future climate scenarios for the region of central and southern Africa depicted that some areas where precipitation are likely to have increases while other, precipitation will reduce. The region northern Zambia and southern Congo showed increases while the northern Congo basin showed reductions. Further south in southern African region, there is a tendency of decreases in precipitation. To the west, in Angola, inland showed increases while towards the coast highlighted some decreases in precipitation. On a global scale, hydropower is likely to experience slight changes (0.08%) due to climate change by 2050. Africa is projected for a slight decrease (0.05%), Asia with an increase of 0.27%, Europe a reduction up to 0.16% while America is projected to have an increase of 0.05%. In the eastern African region, it was shown that hydropower production is likely to increase by 0.59%, the central with 0.22% and the western with a 0.03%. The southern, and northern African regions were projected to have reductions of 0.83% and 0.48% respectively. The basins with increases in flow projections have a slight increase on hydropower production but not proportional to the increase in precipitation. The basins with decreases had even high change as the reduction was further increased by evaporation losses. The hydropower production potential of most of southern African basins is likely to decrease in the future due to the impact of climate change while the central African region shows an increasing trend. The hydropower system in these regions will be affected consequently. The hydropower production changes will vary from basin to basin in these regions. The Zambezi, Kafue and Shire river basins have negative changes while the Congo, Kwanza and Kabompo river basins have positive changes. The hydropower production potential in the Zambezi basin decreases by 9 - 34%. The hydropower production potential in the Kafue basin decreases by 8 - 34% and the Shire basin decreases by 7 - 14 %. The southern region will become drier with shorter rainy seasons. The central region will become wetter with increased runoff. The hydropower production potential in the Congo basin reduces slightly and then increases by 4% by the end of the century. The hydropower production potential in the Kwanza basin decreases by 3% and then increases by 10% towards the end of the century and the Kabompo basin production increases by 6 - 18%. It can be concluded that in the central African region hydropower production will, in general, increase while the southern African region, hydropower production will decrease. In summary, the analysis has shown that the southern African region is expected to experience decreases in rainfall and increases in temperature. This will result in reduced runoff. However the northern part of southern Africa is expected to remain relatively the same with slight increase, moving northwards towards the central African region where mainly increases have been registered. The southern African region is likely to experience reductions up to 5 - 20% while the central African region is likely to experience an increase in runoff in the range of 1 - 5%. Lack of data was observed as a critical limiting factor in modelling in the central and southern Africa region. The designs, plans and operations based on poor hydrological data severely compromise performance and decrease efficiency of systems. Climate change is expected to change these risks. The normal extrapolations of historical data will be less reliable as the past will become an increasingly poor predictor of the future. Better (observed) data is recommended in future assessments and if not better tools and methods for data collection/ should be used. Future designs, plans and operations should include and aspect of climate change, if the region is to benefit from the climate change impacts.

Made available in DSpace on 2015-05-14T12:09:40Z (GMT). No. of bitstreams: 1 parte2.pdf: 1500075 bytes, checksum: 38d49cb673692e0f852411fc280a488d (MD5) Previous issue date: 2006-03-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Nowadays, problems including urban drainage are increasing with the percentage of urban area. In fact, the quality of life in big cities is directly affected by the drainage problems. In case of special areas, such as a closed watershed, the problems are increasing because in this sort of watershed there is not an outlet. This peculiar characteristic in its relief or its soil uses originates diversified questions about hidrology, sedimentology and water quality. In this paper, it was made a study about urban drainage problems in a watershed called Lagoa do Buracão, in the city of João Pessoa, State of Paraíba, Brazil. Each feature of the studied area was researched and several hydrological simulations were made in order to analyze three different sceneries of the soil occupation. The sceneries include changes in the level of the lake. It was used rainfall data and physical characteristics of the studied watershed. The results showed that the satisfactory scenery is the first one. Important positive impacts are involved with the proposed solution as well as negative impacts too. The main conclusion is that the proposal solution is highly recommendable for the resolution of the problem of urban drainage of Lagoa do Buracão. It adds other functions as the creation of a desirable landscape in the composition of the urban space, the valuation of the neighboring areas and the restoration of the environment which is currently degraded. / A problemática das inundações e dos alagamentos urbanos vem crescendo paulatinamente nas últimas décadas como conseqüência, principalmente, do crescimento das áreas urbanizadas. Logo, nota-se o comprometimento da qualidade de vida do habitante urbano, em particular no que tange aos transtornos causados pela presença de água em excesso nas vias e lotes urbanos. Tal situação agrava-se caso se considere a ocorrência desta problemática em bacias fechadas (ou endorreicas), uma vez que neste tipo de bacia o escoamento superficial se acumula em lagos ou sumidouros que não se comunicam por uma rede superficial com outros cursos de água a jusante. Constituem, desse modo, entes especiais na abordagem da gestão do meio urbano por não apresentarem uma saída natural para o escoamento das águas pluviais. A avaliação de áreas especiais fornece subsídios para a gestão do meio urbano, possibilitando o tratamento combinado das questões de drenagem pluvial com outras questões urbanísticas para o desenvolvimento sustentável. Na presente pesquisa, estudou-se a problemática da drenagem urbana de uma bacia fechada denominada Lagoa do Buracão, localizada no bairro de Oitizeiro, município de João Pessoa, Estado da Paraíba. Após caracterização detalhada dos diversos aspectos relativos à área enfocada e de variáveis hidrometeorológicas pertinentes, simulou-se o comportamento hidrológico-hidráulico do conjunto bacia-lagoa a partir da modelagem efetivada com o auxílio do Software ABC 6. São considerados três cenários propostos simulados a partir de uma cenário base, que corresponde a conformação atual da área. Os cenários propostos incluem desassoreamento e aprofundamento da lagoa. Os resultados mostraram que a alternativa mais adequada seria a do cenário 1, que abrange desassoreamento da lagoa para profundidade constante de 3 metros e soleira do vertedor na cota 30,5. Com base neste cenário eleito, propõe-se uma solução de drenagem para a lagoa de uso multifuncional, combinando a utilização de técnicas compensatórias de drenagem urbana e a inserção de elementos que propiciem a requalificação da paisagem urbana. São apontados ainda os principais impactos positivos e negativos esperados da implementação desta intervenção na bacia. Conclui-se que a solução proposta é altamente recomendável para a resolução do problema de drenagem urbana da Lagoa do Buracão, agregando outras funções como a criação de uma paisagem que valoriza as áreas do entorno e restaura um ambiente atualmente degradado.