A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree Master of Science in Quantitative Conservation Biology, 1993 / The aim of the study was to provide a basis for the determination of acceptable hippo densities along the Crocodile River, outside the Kruger National Park. Hippo densities have to be acceptable to land-user~, who suffer hippo damage, and to the conservation authority, responsible for the resources along the river. Hippo nllmbers and distribution in the study area were determined by using a combination of aerial census and ground count. The hippo population number was estimated at 88 animals. Hippo distribution was influenced by flow speed of water. No hippos were observed in river sections with steep gradients, (>6.0 m/km) , while major herds were observed at low gradients «3.5 m/km). A mean density of 0.6 hippo per km was calculated, with a maximum of 2,5 hLppoe Zkm at Kaapmuiden, next to the Kruger National Park. TPA Nature Conservation records on hippo complaints were analyzed, and no relationship between the occurrence of hippo damage and hippo density could be found. There were strong indications that hippo damage are caused by individual problem hippo , The majority of land-users (92 %) supported the conservation of hippos. The size of the area available to hippo was determined for distances of 5 kn. up- and downriver from the major hippo herds. hippo could move away from the river was 336 restriction when compared to the generally assumed hippo grazing range of 3.2 km. Hippo access to grazing was assessed by determining the effective grazing area. / MT2017

The sedimentary rocks of the Karoo Supergroup in the Tuli Basin (South Africa) consist of various terrigenous clastic and chemical deposits (parabreccias, conglo-breccias, conglomerates, sandstones, fine-grained sediments, calcretes and silc~etes). Four stratigraphic units were identified: the Basal, Middle and· Upper Units, and the CI~rens Formation. The palaeo-environmental reconstructions of the four stratigraphic units are based on evidence provided by primary sedimentary structures, palaeo-flow measurements, clast size/shape analysis, petrographic studies, palaeontological findings, borehole data and stratigraphic relations. The facies associations of the Basal Unit are interpreted as colluvial fan and low sinuosity, braid~d river channel with coal-bearing overbank and thaw-lake deposits. The interpreted depositional environment implies a cold climate, non-glacial subarctic fluvio-Iacustrine system. The current indicators of the palaeo-river system suggest flow direction from ENE to WSW. The lithologies of the Basal Unit are very similar to the deposits of the fluvial interval in the Vryheid Formation (Ecca Group) of the main Karoo Basin. There is no indubitable evidence for glacial activity (e.g. striated pavements or clasts, varvites, etc.), therefore the presence of unequivocal Dwyka Group correlatives in the Tuli Basin remains uncertain. The sedimentary structures and palaeo-current analysis indicate that the beds of the Middle Unit were deposited by an ancient river system flowing in a north-northwesterly direction. A lack of good quality exposures did not allow the reconstruction of the fluvial style, but the available data indicate a high-energy, perhaps braided fluvial system. The lack of bio- and chronostr~~igraphic control hampers precise correlation and enables only the lithocorrelation of the Middle Unit with other braided river systems either in the Beaufort Group or in the Molteno Formation of the main Karoo Basin. The depositional environment of the Upper Unit is interpreted as a low-sinuosity, ephemeral stream system with calcretes and silcretes in the dinosaur-inhabited overbank area. During the deposition of the unit, the climate was semi-arid with sparse precipitation resulting -iFlhighmagnitude, low-frequency devastating flash floods. The sediments were built out from a distant northwesterly source to the southeast. The unambiguous correspondence between the Upper Unit and the Elliot Formation (main Karoo Basin) is provided by lithological similarities and prosauropod dinosaurs remains. The palaeo-geographic picture of the Clarens Fonnation indicates a westerly windsdominated erg environment with migrating transverse dune types. The ephemeral stream deposits, fossil wood and trace fossils are only present in the lower part of the Formation, indicating that the wet-desert conditions were progressively replaced by dry-desert conditions. Based on lithological and palaeontological evidence, the Formation correlates with the Clarens Formation in the main Karoo Basin. At this stage, it remains difficult to establish the exact cause of the regional palaeo-slope changes during the deposition of the Karoo Supergroup in the Tuli Basin. It is probable that foreland system tectonics, which affected the lower part of the Supergroup (Basal Unit and Middle Unit?), were replaced by incipient continental extension and rift related tectonic movements in the Middle and Upper Units, and Clarens Formation.

This thesis identifies determinants of market participation of smallholder sorghum and millet farmers and proposes strategies for improving their market participation. The study used survey data from 195 smallholder communal and resettled farmers, and agribusiness firms dealing with sorghum and millet. The farmers were selected from three sorghum and millet producing districts of Zimbabwe. The firms were located in Bulawayo and Harare. Data was collected through face-to-face interviews with the sampled farmers and firm representatives. The thesis also explores the way the small grains have been marketed and the extent of field crop contracting in Zimbabwe. In addition, literature on determinants of market participation for other commodities was reviewed. Recommendations were then drawn on strategies for improved market participation for smallholder farmers. Transaction cost related factors are an important component of marketing that determines the extent of market participation for smallholder farmers. Results of the multiple regression and the probit models showed that transaction cost related factors, such as previously agreed prices (PRICEAGREE), confidence and trust in the buyer (CONFIDENCE), the difference in price knowledge (PRICEKNOW) and delayed payment for sold grain (DELAYPAY) have a significant impact on the quantity of grain sold and the extent of smallholder farmer participation in the market. Discriminant analysis was used to identify factors discriminating sorghum and millet sellers and non-sellers. The division was made according to whether or not a household sold sorghum and/or millet during the period 2004/05 to 2006/07. Of the fourteen potential discriminating variables, six explained group differences with statistical significance. The six important variables in the discriminant function analysis were: number of donkeys owned by a household, crop production levels, source of household income, method of transporting grain to the market, district and area cultivated. Five of the six discriminating variables point to wealth-ranking factors (household asset endowments) implying that poorer households are unable to participate in markets effectively. Farmers identified issues that need to be addressed for sorghum and millet production and marketing to be improved. The identified issues offer guidelines for priority areas to focus on when addressing limitations that are currently inhibiting farmer market participation. The major issues which included; seed unavailability, lack of access to draft power, lack of access to fertilizer, establishment of irrigation schemes; provision of transport to the market, production of marketable surplus and establishing a local market, all point to the need for external assistance to farmers. A review of literature confirms that contracting is an effective way to coordinate and promote production and marketing in agriculture. Sorghum and millet can be grown under contract successfully. The presence of successful contracts for other commodity crops is an indicator of the potential to increase marketing of sorghum and millet through contracting. However, for contracting to succeed, it is necessary to improve sorghum and millet productivity with an assured quality of the grain. The conclusion is that small grains are important food crops for smallholder farmers in drier environments but their productivity is low. Hence, to enhance farmer access to markets, it is necessary to increase the productivity of sorghum and millet and thus, enable smallholder farmers to produce adequate marketable surplus. Interventions by government and private sector should aim at addressing the major factors that determine market participation. Important to note is that, if poorer households are unable to effectively participate in markets, then interventions to increase households’ productive assets or the public goods that support agricultural production and marketing may be necessary. Based on the study findings, the thesis proposes possible key intervention ingredients for successful contracting of sorghum and millet in Zimbabwe. An enabling environment and legal framework created by government and private sector, addressing identified priority areas, primarily will largely determine the level of market participation of smallholder farmers in Zimbabwe. Copyright / Dissertation (MScAgric)--University of Pretoria, 2010. / Agricultural Economics, Extension and Rural Development / unrestricted

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Hydrogeology. July 2017. / Hydrogeological research was undertaken in the transboundary Ramotswa dolomitic aquifer to provide understanding and quantification of the processes governing recharge mechanism and rates, in order to promote efficient and sustainable groundwater resource utilization and development, as well as to improve the Ramotswa transboundary aquifer management. Hydrochemical and tracer approaches were utilized to evaluate the processes governing the recharge mechanism while the chloride mass balance approach was further applied to assess groundwater recharge rates. Results indicated that all groundwater samples contained detectable amounts of tritium highlighting the renewability of the transboundary Ramotswa aquifer resources. Two distinct water types were characterised: sub-modern waters approximately recharge prior to the 1950s and a mixture of modern and sub-modern waters of recently recharge rainfall indicative of active recharge in the area through intensive rainfall. Correlation between δ18O and δ2H, and soil Cl- indicated that groundwater recharge in the Ramotswa dolomitic aquifer takes place mainly by two flow mechanisms: a displacement of moisture through a diffuse or piston flow through permeable soils and from concentrated runoffs due to surface depressions, and a preferential flow component through fractures that outcrop at surface and riverbed infiltration along the ephemeral Notwane River. Annual groundwater recharge estimates varied from 0.4% MAP to 12% MAP and from 5% MAP to 14% MAP within the northern parts and the southern parts of the study area, respectively. Recharge estimates correlated well with the proposed mechanism of flow both in the southern and in the northern parts of the study area as well as with the previous studies conducted within the greater Ramotswa area. A way forward to ensure the long-term sustainability of the transboundary Ramotswa aquifer resources is recommended, such as to preserve and protect potential recharge areas through carefully controlled land use planning and development, and to equate abstraction rates to average recharge rates, which has to be subjected to the Limpopo Watercourse Commission. / MT2018

After the International Conference on Water and Environment in Dublin in 1992, the four socalled Dublin Principles created new managerial approaches for the water sector. This case study, which was conducted in the Limpopo Basin in Mozambique, examined the performance in the implementation of the principle related to “water development and management based on a participatory approach involving users, planners and policy makers at all levels”. The study was motivated by the fact that experience with the implementation of this principle in the Limpopo Basin of Mozambique has not delivered the anticipated outcomes. To this effect, this study analysed the history and performance of the decentralization process in the Limpopo Basin, and the factors that might have contributed to the outcomes we observe The methodology employed by the study was based on the framework for institutional analysis of decentralization reforms in natural resource management proposed by Dinar et al. (2005), Kemper et al. (2006), and Blomquist et al. (2008). This framework recommends that for the decentralization process to be successful, the following pre-requisites must be in place: (1) financial assistance from the state to enable basin level stakeholders to establish some of the organisations; (2) actors' participation and equitable representation of different segments of society, and acceptance of it from the communities; (3) the presence of basinlevel institutions, availability of forums for information sharing, communication and for conflict resolution; and (4) legitimacy, relevant human capacities and adequate financial resources among the River Basin Organizations (RBOs). The results from this study indicate that in as much as the Water Law, the Regulations of Water Services Provision and the Water Policy in Mozambique created the basis for the decentralization of water resources management, the operationalisation of the process has not been successful, considering that the prerequisites for an effective and sustainable decentralization process as postulated by Blomquist, Dinar and Kemper are still lacking. The study established that incentives for the decentralization process were not linked to the scarcity of water. The study further established that most prerequisites postulated by Blomquist, Dinar and Kemper were not satisfied, in particular: (1) the financial assistance from the state to enable basin level stakeholders to establish some of the organisations is inadequate; (2) the actors' participation and equitable representation of different segments of society with interest in water resources management is not satisfactory; and (3) the legitimacy, relevant human capacities and adequate financial resources for effective functioning of the Water Users Associations (WUAs) are still lacking. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2012. / Agricultural Economics, Extension and Rural Development / unrestricted

Severe flooding events in subtropical southern Africa are not uncommon and can cause damage to infrastructure, lead to huge economic losses, and fatalities. Although extreme rainfall events can have far-reaching negative consequences, they can also provide large amounts of freshwater within a short time span, which supports the rain-fed farming upon which much of the population depends. However, the mechanisms through which extreme rainfall is produced in southern Africa are still not well understood. In particular, relatively little is known about where the moisture, a key ingredient in the rainfall, is sourced and how it is transported into the region. This thesis aims to address some of the gaps in this understanding by examining the moisture sources and subsequent moisture transport moisture into one of the key river basins in southern Africa, the Limpopo River Basin (LRB). The LRB, located in eastern southern Africa and spanning four countries, has experienced a number of extreme flooding events over the last three decades. Using CHIRPS satellite merged rainfall data for 1981-2016, the thesis identified the top 200 heavy extreme rainfall events in the LRB and the associated weather systems. It was found that tropicalextratropical cloud bands account for almost half of the events and tropical lows are responsible for just over a quarter. The remaining quarter of the events are associated with mesoscale convective systems and cut-off lows, the latter more important during transition seasons. Most of the events occur in the late summer when tropical lows and cloud bands are more common. Some relationships between the frequency of heavy rainfall events over the LRB and interannual climate modes of variability such as ENSO, SIOD, and SAM were found. Having examined the annual cycle of the top 200 heavy rainfall events, the analysis then applied the Lagrangian trajectory model HYSPLIT, with NCEP II reanalysis data as input, to backtrack air parcels from the LRB to their moisture source on seasonal scales and in terms of the types of weather systems involved. The resulting trajectories show that the seasonal transport of moisture over the LRB originates from seven moisture source regions; namely, local continental, tropical southeast Atlantic Ocean, midlatitude South Atlantic Ocean, tropical Northwest Indian Ocean, tropical southwest Indian Ocean, subtropical southwest Indian Ocean, and the Agulhas Current. Important differences in moisture source regions and pathways exist between early (OctoberDecember) and late (January-April) summers, with the tropical northwestern Indian Ocean and the northern Agulhas Current sources more prominent during JFMA than OND. Generally, moisture v source regions and transport pathways for LRB tend to be influenced by both the regional summer season circulation and the synoptic systems involved. Thus, it was found that cloud band and tropical low events within the top 200 tend to have the Congo Basin as an important moisture source whereas this source is less evident for cut-off low events. To help assess the robustness of the composite synoptic approach, the final part of the thesis applied the Lagrangian analysis to the most severe case in the top 200 events over the LRB (11- 21 January 2013). It was found that this case was largely linked to three main moisture sources: (1) tropical northwest Indian Ocean, (2) the Agulhas Current / Mozambique Channel, subtropical Southwest Indian Ocean, and (3) continental sources over the Congo Basin and northern Tanzania. Generally, the moisture source regions and pathways for the January 2013 event agreed with the climatological moisture source regions over the LRB, apart from the obvious absence of the tropical southeast Atlantic source in this case. In general, the thesis has provided a better understanding of the characteristics of heavy rainfall events over the LRB in terms of their associated weather systems, seasonality, interannual variability, and moisture source regions and trajectories.

Thesis (MA)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The Crocodile River Greenbelt area, located along the northern edge of Nelspruit, is a unique ecological system that must be protected from encroaching urbanization and invasive alien vegetation. The writer has attempted through policy intervention to achieve this goal. A policy for a greenbelt was compiled to allow for limited development along the Crocodile River Greenbelt area. The first step was to compile a policy for the Crocodile River Greenbelt area, and to contextualise the legislative requirements to compile such a policy. The second step was to discuss the State of Environment Report, which was compiled for the Crocodile River Greenbelt area and reflects directly the physical environment of the policy area. The third step was to lay the foundation of the policy by discussing guiding principles for open space systems. These principles form the basis of the policy. The fourth step was the compilation of the policy itself, which is underpinned by a spatial framework to guide the future physical development of the area. As conservation of the Crocodile River Greenbelt area is the main objective of the policy as well as allowing for limited development within the urban area, a management structure was proposed as Step 5 to achieve these objectives. / AFRIKAANSE OPSOMMING: Die Krokodilrivier-groengordelgebied is in die noordelike deel van Nelspruit geleë en is 'n unieke ekologiese stelsel wat beskerm moet word teen verstedeliking en indringer plante. Die skrywer poog deur 'n beleidsintervensie om hierdie doel te bereik. Die beleid vir 'n groengordel is saamgestelom voorsiening te maak vir beperkte ontwikkeling in die Krokodilrivier-groengordelgebied. Die eerste stap om so 'n beleid saam te stel vir die Krokodilrivier-groengordelgebied was om dit te kontekstualiseer binne die wetlike vereistes vir so 'n beleid. Die tweede stap was om die resultate van die Omgewings-toestandsverslag, wat vir die Krokodilrivier-groengordelgebied opgestel is en die fisiese omgewing van die beleidsgebied opsom, te bepreek. Die derde stap was om die rigtingewende beginsels van oopruimtes te bespreek wat die grondslag van die beleid vorm. Die vierde stap was die saamstel van die beleid self, wat gerugsteun word deur die grondgebruik plan wat toekomstige fisiese ontwikkeling van die gebied rig. Omdat bewaring van die Krokodilrivier-groengordelgebied die hoofdoel van die beleid is, tesame met beperkte ontwikkeling binne die stedelike gebied, is in Stap 5 'n bestuurstruktuur voorgestelom hierdie doel te bereik.

Thesis (D. Phil.(International Politics))--University of Pretoria, 2003. / Includes bibliographical references.

The aim of this thesis has been to reconstruct paleoenvironment, paleohydrology and paleoclimate in coastal southern Mozambique, with emphasis on tracing past flooding events on the lower Limpopo River floodplain. In order to extend flood chronologies beyond periods covered by instrumental data, sediments from lakes on the floodplain were studied (Lake Lungué, Coassane Oxbow, Lake Magandane and Lake Soane). Past sea-level variations and climate changes were deduced by analyzing sediments from coastal sites north of the floodplain area (Lake Chilau, Lake Nhauhache and Macassa Bay). To achieve the established objectives, a multi-proxy approach was applied on most of the retrieved sediment cores, involving analysis of mineral magnetic parameters, grain-size and organic carbon in combination with analysis of microfossils such as diatoms and/or phytoliths. Chronologies for the constructed time-series analysis were obtained by radiocarbon dating and age-depth modelling. The synthesized data from the sampled sites on the Limpopo River floodplain suggest that the area was affected by at least 16 flooding events of variable magnitudes during the studied period. These are dated to c. AD 940, 980, 1040, 1100, 1250, 1300, 1370, 1580, 1665, 1730, 1755, 1855, 1920, 1945, 1970 and 2000. In calibrated years BP these ages correspond to 1010, 970, 910, 850, 700, 650, 580, 370, 285, 220, 195, 95, 30, and 5 cal yrs BP. The two youngest are dated to 20 and 50 years AP (After Present being 1950). Proxy data further suggest that southern Africa was subject to two periods of sea-level highstands, at c. 5000–4200 BC (6950–6150 cal yrs BP) and AD 300–950 (1650–1000 cal yrs BP). The former represents the middle part of the postglacial climatic optimum. The wettest period in the Limpopo River floodplain was reported between AD 1360 and 1560 (590 and 390 cal yrs BP) in the Lake Lungué record, while Lake Chilau experienced wet conditions between AD 1200 and 1400 (750 and 550 cal yrs BP), then returning to drier conditions that prevailed until c. AD 1600. In Lake Nhauhache, however, drier conditions prevailed from c. AD 1200–1700 (750–250 cal yrs BP), shifting towards wetter at c. AD 1900 (50 cal yrs BP). The deviating signals between records can partly be explained by Lake Lungué basin being located on the Limpopo River floodplain, responding to flooding events associated with precipitation upstream the drainage area. Therefore, wet and dry periods in floodplain lakes (e.g. Lake Lungué) are not expected to correlate with precipitation changes on a local scale, as indicated by e.g. Lake Nhauhache. This is supported by a relatively weak agreement between Lake Lungué record and other nearby records (outside the floodplain), but a better correlation with records from the upper catchment, where a more regional climate signal is provided of the southern African summer rainfall region. / Denna avhandling behandlar studier av paleomiljöer i södra Mozambique med fokus på översvämningshistorik i Limpopo-flodens nedre lopp. Tidsspannet är mitt- och sen-holocen och inkluderar även klimat och havsnivåvariationer. Följande analysmetoder har applicerats på ett flertal sedimentkärnor för att belysa ovanstående frågeställningar: mineralmagnetiska parameterar, kornstorlek, organiskt kol samt kiselmikrofossil (diatoméeter och fytoliter). Åldrar har bestämts med 14C-metoden.  Analyserna visar att mineralmagnetiska parametrar är lämpliga för att identifiera översvämningar, speciellt magnetisk susceptibilitet och SIRM. Dessa parametrar visar på ett sediments magnetiska kornstorlerkar och koncentrationen av finkorniga magnetiska mineral. Även kornstorleksanalyser fungerade som ett bra komplement till dessa metoder. Sammantaget har ett minimum av 16 översvämningar registrerats i Limpopo/flodens nedre lopp under de senaste 1100 åren. Särskilt stora översvämningar har daterats till AD 1250 (700 kal år BP), AD 1370 (580 kal år BP), AD 1580 (370 kal år BP), AD 1855 (95 kal år BP), AD 1920 (30 kal år BP), AD 1970 (20 kal år AP) och AD 2000 (50 kal år AP), där AP betyder ”after present”, vilket är 1950. Mindre kraftiga översvämningar har daterats till AD 940 (1010 kal år BP), AD 980 (970 kal år BP), AD 1040 (910 kal år BP), AD 1100 (850 kal år BP), AD 1300 (650 kal år BP), AD 1665 (285 kal år BP), AD 1730 (220 kal år BP), AD 1755 (195 kal år BP) och AD 1945 (5 kal år BP). Skriftliga källor visar på att åtminstone åtta översvämningar har ägt rum under de senaste 62 åren. Under samma period har denna undersökning registrerat två händelser, vilket indikerar att endast ett fåtal har registrerats med ovan nämnda metoder. Det är sannolikt att sedimentationsmönstret under en översvämning är komplicerat och inte heller likartad från gång till gång. Detta innebär att ett flertal sedimentkärnor behöver analyseras och dateras väl. Ytterligare en försvårande faktor är flodens mycket aktiva meandringsaktivitet. Analys av diatoméer har visats vara värdefulla när det gäller översvämningshistorik, klimatförändringar och havsytevariationer. Sedimenten i den något till flodslättens nedre lopp perifert belägna sjön Lungué indikerar fuktiga förhållanden mellan AD 1360 och 1560 (590 till 390 kal år BP). Kombinerade fytolit- och diatoméanalyser av sedimenten i sjön Chilau indikerar fuktiga förhållanden från AD 1200 till 1400 (750 till 550 kal år BP), varefter torrare förhållanden rådde till ca AD 1600 (350 kal år BP). Diatoméanalys av sedimenten i sjön Nhauhache indikerar generellt sett torrare förhållanden mellan AD 1200 och AD 1700 (750 till 250 kal år BP) då klimatet blev fuktigare. De fuktiga och torra förhållanden som dokumenterats i sjön Lungué och översvämningshistoriken korrelerar inte helt med lokala nederbördsförhållanden. Däremot stämmer erhållna data bättre med förhållanden i den övre delen av Limpopoflodens dräneringsområde. Även sjöar och fyllda meanderbågar på själva flodslätten verkar reagera tydligare på översvämningar orsakade av nederbörd i den övre delen av flodloppet. Undersökningen indikerar två faser av en förhöjd havsyta längs kusten i södra Mozambique. En äldre fas är daterad till ca 5000–4200 f.Kr. (6950–6150 kal år BP), vilken representerar den mellersta delen av det postglaciala värmeoptimet. Denna tolkning stöds även av andra undersökningar. En yngre fas har daterats till AD 300–950 (1650–1000 kal år BP), vilken korresponderar till en period med något förhöjda temperaturer i ett globalt perspektiv. / O presente projecto teve como objectivo a reconstrução do paleoambiente, paleohidrologia e paleoclima da costa Sul de Moçambique, com ênfase na identificação de vestígios de eventos de cheias que tenham, no passado, afectado a planície de inundação do Rio Limpopo, com vista a fazer a extensão das datações de cheias para o período anterior aos instrumentos de medição. Deste modo, foram estudados sedimentos recuperados através de testemunhos de sondagem em lagos dentro da planície de inundação (Lago Magandane, Lago Lungué, Lago Soane e o canal abandonado Coassane). As variações do nível do mar e mudanças climáticas do passado foram deduzidas a partir da análise de sedimentos de áreas costeiras a norte da planície de inundação (Lago Chilau, Lago Nhauhache e a Baía de Macassa). Para o alcance destes objectivos, os sedimentos dos testemunhos de sondagem recuperados foram submetidos a várias análises laboratoriais que incluem propriedades de minerais magnéticos, granulometria, teor de matéria orgânica e de microfósseis (diatomáceas e fitólitos). Para o estabelecimento do modelo cronológico foram usadas datações pelo método 14C feitas em matéria orgânica, assim como conchas de gastrópodes e bivalves. A combinação dos resultados obtidos para os pontos de amostragem localizados dentro da planície de inundação do Rio Limpopo, sugerem que esta área foi afectada por um mínimo de 16 eventos de cheias de variada magnitude nos últimos 1100 anos. As cheias de alta magnitude tiveram lugar nos anos 1250, 1370, 1580, 1855, 1920, 1970 e 2000. Por seu turno, as cheias de magnitude moderada ocorrerram nos anos 940, 980, 1040, 1100, 1300, 1665, 1730, 1755 e 1945.. Os anos a negrito são indicativos de eventos de cheias de alta magnitude. O número total de eventos identificados no presente estudo é um mínimo que poderá ter afectado a planície de inundação, tendo em consideração que fontes escritas reportam a ocorrência de pelo menos oito eventos nos últimos 62 anos, tendo o presente estudo revelado somente dois. Isto indica que apenas eventos de cheias intensos podem ser revelados pelos métodos aplicados nesta investigação. Adicionalmente, este estudo mostra a necessidade de aumentar o número de pontos de amostragem para permitir a identificação de mais eventos de cheias ocorridos no passado, devido à diferenciada resposta sedimentológica e geomagnética às cheias, a qual se encontra directamente relacionada à distância do rio meandrante. As análises de microfósseis de diatomáceas permitiram reconstruir o paleoclima e as influências do nível do mar nas áreas de estudo deste projecto. Os registros de diatomáceas do Lago Lungué indicam um período húmido entre AD 1360 e 1560. No Lago Chilau, dados de diatomáceas e fitólitos sugerem condições de humidade entre AD 1200 e 1400. Por seu turno, no Lago Nhauhache, condições de seca dominam entre AD 1200 e 1700. As condições de seca e humidade documentadas no Lago Lungué e os eventos de cheias revelados pelos sedimentos analisados da planície de inundação do Rio Limpopo não mostram total correlação com períodos de baixa e alta precipitação a nível local, mas apresentam boa correlação com evidências a montante na área de drenagem do Rio Limpopo. Em geral, lagos activos ou preenchidos por sedimentos mostrarão ser mais susceptíveis a cheias com origem a montante do que a nível local. As investigações conduzidas permitiram identificar dois períodos de alto nível do mar na região sul de Moçambique. A fase mais antiga teve lugar há cerca de 5000–4200 BC (6950–6150 anos do calendário BP), representando a fase mais recente do pós-glaciar climático óptimo (postglacial climatic optimum, PCA). A fase recente é datada de AD 300–950 (1650–1000 anos do calendário BP), correspondendo a um período de temperaturas relativamente altas a nível global. / Climate and Environmental Research

Disaster risk reduction policies and practitioners alike emphasise the importance of vulnerability reduction. However, the concept of vulnerability is highly dynamic, and research still strives to understand and capture its complexity. The purpose of this study was to improve the understanding of flood vulnerability in rural disaster-prone communities in Mozambique. To explore previous experiences of floods, I conducted semi-structured interviews with local risk committee members and community members in the lower Limpopo river basin. The findings were analysed with an analytical framework consisting of the Disaster Pressure and Release (PAR) model, drawing on political ecology and the Access model. Disaster was studied as a process revealing important factors, capabilities and strains affecting peoples’ vulnerability. This paper illustrated that rural communities in the lower Limpopo river basin are vulnerable to floods in a variety of ways. The findings presented unsafe conditions such as the fragile local economy, unsafe natural resources, strained physical resources and limited access to human and social capital. Several factors deriving from political, social and economic structures were found to influence specific forms of vulnerability expressed in relation to floods. Therefore, this paper contributes to new insights of how flood vulnerability can be described and explained in Mozambique.