Academic literature on the topic 'Zambezi River Delta'

Abstract. Groundwater plays an important role as a source of water for various socio-economic uses and environmental requirements in the lower Zambezi basin in Mozambique. Hence it is important to know its availability and adequacy in space to inform decision making for sustainable water management practices. For a derivation of a Groundwater Availability map and a Groundwater Adequacy map we adapted the DRASTIC methodology in a GIS environment to determine how different parameters, such as precipitation, topography, soil drainage, land use and vegetation cover, aquifer characteristics and groundwater quality affect (i) groundwater recharge on a long-term sustainable basis, (ii) the short-term abstraction potential and (iii) the long-term adequacy of groundwater utilization for domestic use. Results showed that groundwater availability in the Zambezi basin varies mostly from medium to low, with highest potential along the perennial rivers and in the delta where it plays a crucial role in environmental preservation. The southern margin of the Zambezi River shows low groundwater availability and also presents low adequacy for domestic use due to poor groundwater quality. The results from this study will be used in determining the most promising future development pathways and select the most attractive strategic development plans of the Mozambican government for the Lower Zambezi basin.

This study aims at documenting the value chain derived from mangrove forests in selected sites in central Mozambique (Zambezi Delta, Nhangau and Chiveve River), through the identification of the services delivered by mangrove forests and assessment of stakeholder’s engagement within the value chain. Furthermore, this work evaluates the income pathways as well as the current and potential benefits of different stakeholders and the socio-economic sustainability of mangroves in the three regions. Zambezi Delta is one of largest mangrove swamps in Africa and Chiveve is located in Beira City, impacted by Cyclone Idai in 2019. The main benefits obtained by the communities both in the Zambezi Delta and Nhangau were derived from commercially important wood extraction and honey production for domestic use. Within the Zambezi Delta, profit for small mangrove poles accrued at the wholesale level (82.6%), while that for large poles accrued to harvesters (125.0%), after a small initial direct investment. At Nhangau, small poles fetched profits of 17%, medium poles 11.5%, and large poles 24%; for charcoal, the greatest portion of profits went to retailers at 50%. Men were mostly involved in mangrove wood harvesting for commercial purposes, while women collected firewood mainly for domestic use. At the Chiveve, the community benefited predominantly from non-extractable services such as flooding control, water purification, nursery grounds for fisheries and aesthetic beauty. It is suggested that Mozambique mangrove forests are valued at USD 2 400 per hectare per year. This monetary accounting can be used to inform decision making on mangrove management and to improve the performance of the value chain and the wellbeing of local communities.

AbstractPopulations of the common hippopotamus Hippopotamus amphibius in Mozambique were surveyed in 2010 during a national survey of the crocodile Crocodylus niloticus. Numbers of hippos seen during aerial counts along major rivers and lake shores were corrected to allow for undercounting of groups and these data were supplemented with the results of other recent surveys. There are now estimated to be c. 3,000 hippos in Mozambique and c. 50% of these live in Lake Cabora Bassa or the Zambezi River. The national total is much lower than the figure of 16,000–20,500 hippos estimated in 1986, used for the latest (v. 2012.1) IUCN Red List. The 1986 total included an estimated 10,000–12,000 in Marromeu Complex, an area that includes the southern Zambezi delta. We review the results of past surveys and find that the number of hippos in Marromeu Complex in 1986 was probably three times fewer than estimated. Although the number of hippos in this area declined markedly during the 1980s we believe that the 1986 overestimate of hippos in Marromeu Complex is an error that has been perpetuated for 25 years. Particular care should be taken when Red List assessments roll-over old and unsupported estimates of numbers. Even if an old estimate was accurate there comes a time when it should not simply be rolled-over. The 2007 IUCN Species Survival Commission's African Elephant Status Report provides a model for future assessments of the status of the common hippopotamus, categorizing the numbers of a species according to the type of survey, its reliability, and how long ago it was conducted.

Abstract. Water infrastructure investment planning must consider the interdependencies within the water–energy–food nexus. Moreover, uncertain future climate, evolving socio-economic context, and stakeholders with conflicting interests, lead to a highly complex decision problem. Therefore, there is a need for decision support tools to objectively determine the value of investments, considering the impacts on different groups of actors, and the risks linked to uncertainties. We present a new open-source hydro-economic optimization model, incorporating in a holistic framework, representations of the water, agriculture, and power systems. The model represents the joint development of nexus-related infrastructure and policies and evaluates their economic impact, as well as the risks linked to uncertainties in future climate and socio-economic development. We apply the methodology in the Zambezi River basin, a major African basin shared by eight countries, in which multiple investment opportunities exist, including new hydropower plants, new or resized reservoirs, development of irrigation agriculture, and investments into the power grid. We show that it is crucial to consider the links between the different systems when evaluating the impacts of climate change and socio-economic development, which will ultimately influence investment decisions. We find that climate change could induce economic losses of up to USD 2.3 billion per year in the current system. We show that the value of the hydropower development plan is sensitive to future fuel prices, carbon pricing policies, the capital cost of solar technologies, and climate change. Similarly, we show that the value of the irrigation development plan is sensitive to the evolution of crop yields, world market crop prices, and climate change. Finally, we evaluate the opportunity costs of restoring the natural floods in the Zambezi Delta; we find limited economic trade-offs under the current climate, but major trade-offs with irrigation and hydropower generation under the driest climate change scenario.

Thesis (MEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The Zambezi River is the largest east-draining river in Africa. It captures runoff from 8 different countries before draining into the Indian Ocean in Mozambique through the Zambezi Delta which is recognised as a (Ramsar) Wetland of international importance. The Zambezi River flows are currently regulated by four large hydropower dams within its catchment. Much attention has been given in recent literature to the detrimental effects of the altered flow regime as a result of dams on the Zambezi River and the Delta in particular. Existing research relating to these negative effects includes many detailed ecological, hydrological and qualitative morphological studies but to date no detailed morphological modelling studies have been conducted in this regard. In this thesis a two-dimensional coupled hydrodynamic and morphological numerical model of the Zambezi Delta is created using topographical information obtained from a navigational study (Rio Tinto, 2011). The model hydrodynamics are calibrated using recorded water levels and flows at two gauging stations within the model domain. The bed load sediment transport is calibrated using field measurements (ASP, 2012b). The effects of dams on the Zambezi Delta are investigated by performing two 10 year simulations, one representing the current (post-dam) scenario and the other representing a pre-dam scenario. These simulation results show a significant decrease in flooded areas and sediment movement on the floodplains as a result of dams. Additional effects on channel widths and depth, on bed gradings, and on tidal water level variations are analysed. The model is then used to simulate a proposed environmental flood release scenario. Such releases have been recommended as a means to partially mitigate the negative impacts of dams on the Zambezi River. In this case an annual flood release supplying a peak flow of 8500 m3/s (slightly less than the pre-dam mean annual flood of 10 000 m3/s) was found to cause slightly more flooding of the close floodplains and to have small effects on the river channel width. The model predicts hydrodynamics and bed sediment transport of non-cohesive sediments with suitable accuracy but an issue with the suspended transport of cohesive sediments was identified. Recommendations are made for addressing the suspended sediment transport inaccuracy. The model, in its current form, can provide quantitative information regarding the hydrodynamics and course sediment transport of the general delta region on a coarse scale. With additional computational resources and accurate topographical information the model can be refined to give accurate predictions for localised areas within the delta. Such information would be valuable to specialist studies addressing the environmental effects of various proposed flooding scenarios or future dams.
AFRIKAANSE OPSOMMING: Die Zambezirivier is die grootste oos-dreineerende rivier in Afrika. Dit ontvang afloop van ag verskillende lande voor dit in die Indiese Oseaan in Mozambiek uitmond. Die Zambezidelta work erken as 'n RAMSAR vleiland van internasionale belang. Die vloei in die rivier word tans gereguleer deur vier groot hidro-elektriese damme binne sy opvangsgebied. Baie aandag is in die onlangse literatuur gegee aan die nadelige gevolge van die veranderde vloei as gevolg van damme op die Zambezi Rivier en spesifiek op die Delta. Bestaande navorsing met betrekking tot hierdie negatiewe effekte sluit in detail ekologiese, hidrologiese en kwalitatiewe morfologiese studies, maar tot op datum is geen gedetailleerde morfologiese modelleringstudies gedoen nie. In hierdie tesis is 'n twee-dimensionele gekoppelde hidrodinamiese en morfologiese numeriese model van die Zambezi Delta geskep met behulp van topografiese inligting wat verkry is uit 'n navigasiestudie (Rio Tinto, 2011). Die model hidrodinamika is gekalibreer deur teen watervlakke en vloei by twee meetstasies in die model domein. Die bedvrag sedimentvervoer is gekalibreer met behulp van veldmetings (ASP, 2012b). Die ȉnvloed van die damme op die Zambezi Delta is ondersoek deur twee 10-jarige simulasies, een wat die huidige ( na-dam ) scenario en die ander wat 'n voor-dam scenario ondersoek. Hierdie simulasie resultate toon 'n beduidende afname in die oorstroomde gebiede en sedimentbeweging op die vloedvlaktes as gevolg van damme. Bykomende effekte op kanaalbreedtes en -diepte, op die bedgraderings , en op getywatervlak variasies is ontleed. Die model is vervolgens gebruik om 'n voorgestelde omgewingings vloedloslaating te ondersoek. Sodanige loslaatings is aanbeveel om die negatiewe impak van damme op die rivier gedeeltelik te verminder. In hierdie geval gee 'n jaarlikse vloedloslaating met 'n piekvloei van 8500 m3/s (effens minder as die voor-dam gemiddelde jaarlikse vloed van 10 000 m3/s) effens meer oorstromings van die vloedvlaktes en het 'n klein uitwerking op die rivierkanaalbreedte. Die model voorspel die hidrodinamika en bedsedimentvervoer van nie-kohesiewe sedimente met betroubaarheid, maar 'n probleem met die vervoer van kohesiewe sedimente is geïdentifiseer. Aanbevelings word gemaak vir die aanspreek van die kohesiewe sedimentvervoer onakkuraatheid. Die model, in sy huidige vorm, kan kwantitatiewe inligting oor die hidrodinamika en natuurlik sedimentvervoer van die algemene delta streek by benadering verskaf. Met bykomende rekenaar hulpbronne en akkurate topografiese inligting kan die model verfyn word om akkurate voorspellings vir plaaslike gebiede binne die delta te gee. Sulke inligting kan waardevol wees vir spesialis-studies van die omgewingsimpakte van verskillende voorgestelde vloedloslaatings of toekomstige damme.