The role of economic analysis in groundwater management in semi-arid regions: the case of Nigeria

The aim of this paper is to use an economic framework to derive decision making rules for river basin management with a focus on groundwater resources. Using an example from northern Nigeria, the paper provides an example of how decision making for sustainable water resources management may be facilitated by comparing net benefits and costs across a river basin. It is argued that economic tools can be used to assess the value of water resources in different uses, identify and analyze management scenarios, and provide decision rules for the sustainable use and management of surface and ground water resources in the region.

Volunteer tourism: The case of Habitat for Humanity South Africa

Volunteer tourism as a subset of alternative tourism is the focus of analysis. This paper contributes to the limited writings on volunteer tourism by investigating the activities in South Africa of Habitat for Humanity, a grassroots ecumenical Christian organization that works in partnership with communities to eliminate poverty through the provision of shelter. A profile of the volunteer tourist and of their tourism experience in South Africa is presented which is based largely upon the return of 123 questionnaires from volunteer tourists in South Africa working with the local branch of Habitat for Humanity. This revised version was published online in August 2006 with corrections to the Cover Date.     

Regenerating rural economies: The case of Limehill, South Africa

The issue of the quality of life of rural South Africans has become a key focus of attention of the national and provincial governments in postapartheid South Africa. This focus stems from legislation that enshrines concurrent responsibility for rural development to both these spheres of government. However, post-1995 legislation including the introduction of wall-to-wall municipal authorities and the subsequent initiatives by municipalities to assume responsibility for service delivery in their areas have infused considerable complexity into the development landscape at the local level. Within this context and against the background of different perspectives and strategies for rural development, this paper examines, in a case study of the Limehill Complex within the Ndaka Municipality in KwaZulu-Natal, the specific development problems that the `deep' rural communities experience. The paper then discusses strategic interventions that the Ndaka Municipality, in conjunction with other role players and the different spheres of government, needs to consider for implementation in order to regenerate the rural economy of the Limehill Complex and assist in the alleviation of widespread poverty in the area. This revised version was published online in July 2006 with corrections to the Cover Date.     

Re-balancing racial economic power in South Africa: The development of black small-scale enterprise

This paper examines the problems and prospects of developing black small-scale enterprise as part of the challenge to re-balance racial economic power in South Africa. The findings are presented of several studies identifying major blockages to black small business development. Policy issues of concern include finance, training and urban planning. Considerable importance is attached to the potential for expanding subcontracting linkages between large and small production enterprises.     

Invisible towns: A case study in the cartography of South Africa

Many large Black settlements are downgraded or made invisible on maps of South Africa. This form of subjective generalisation gives a false prominence to small White towns. A more realistic map of the major settlements in South Africa is presented. The problems associated with mapping of Black settlements are discussed. These include the lack of census data, absence of official recognition of places, difficulties of place naming and the lack of functional imcomparability with other places.     

The evolution of coastal barrier systems: a case study of the Middle-Late Pleistocene Wilderness barriers,South Africa

Barrier systems contain lengthy, but complex, records of long-term environmental fluctuations. The Wilderness embayment, South Africa, contains a system of shore-parallel barriers reaching up to 200 m above modern sea level. This study reports the results of chronological, topographical (both on- and off-shore), sedimentological and micromorphological analyses within the Wilderness embayment. Sixty-one new luminescence ages from sixteen sites in unconsolidated dunes and three separate barriers are presented which, when combined with previously published luminescence ages from the area, provide a high-resolution chronological framework for the emplacement and evolution of the barrier system. The preserved barriers have been constructed within at least the last two glacial–interglacial cycles with notable phases between 241–221 ka, 159–143 ka, 130–120 ka, 92–87 ka and post 6 ka. Multiple phases of barrier construction occurred during sea-level highstands, with sediment deposition on each individual barrier occurring over at least two interglacials. Holocene evolution of the system sheds light on earlier events, with dune preservation occurring only during early regression from the Mid-Holocene highstand. Tectonic stability at Wilderness allowed glacio-eustatically formed shorelines to occupy similar positions on multiple occasions. This, in conjunction with a relatively humid climate and a well-vegetated landscape, enabled deflated sediment from beaches to form dunes which stacked upon each other to form an extensive and complex vertical accretionary sequence. Repeated erosion and recycling of pre-existing barriers as well as barrier construction on what is currently the off-shore platform during still-stands in sea-level regressional cycles, when sea levels dropped below ca ?50 m from the present day, has added to the complexity of the preserved terrestrial barrier record. The Wilderness barrier system contrasts with barriers developed elsewhere in the world where higher rates of crustal uplift have allowed preservation of a more complete and more widely spaced palaeorecord. This research also shows the utility of integrating off-shore topography as revealed by bathymetry, with terrestrial topographic data for the better understanding of the evolution of palaeo-coastlines and the preserved dune record found on present-day coastal plains. Local variation in the topography of the continental shelf at Wilderness has generated spatial and temporal complexity within the sedimentary records of individual barriers as well as having a significant influence on preservation.     

Inner city gentrification in South Africa: The case of Woodstock,Cape Town

The focus in this paper is residential change taking place since 1980 in the innercity suburb of Woodstock, Cape Town. This area is significant as it was one of the few multiracial spaces which survived the deliberate whitening of South African cities during the apartheid era. The paper analyses the major threat posed to the longstanding multi-racial complexion of Woodstock by the state's attempt to declare part of the suburb for exclusive coloured residence under Group Areas legislation. Nonetheless, while community resistance in the form of the Open Woodstock campaign was successful in halting enforced residential change, processes of gentrification have shaped a new class composition in this inner-city suburb.     

The economic mineral potential of the mid-Proterozoic Waterberg Group, northwestern Kaapvaal craton, South Africa

The 1900–1700 Ma Waterberg Group in the main Waterberg fault-bounded basin consists of dominantly coarse siliciclastic red beds with minor volcanic rocks. The sedimentary rocks were deposited mainly by alluvial fans, fluvial braidplains and transgressive shallow marine environments, with lesser lacustrine and aeolian settings. Uplifted, largely granitic source areas were located along the Thabazimbi-Murchison lineament (TML) fault system in the south, and along the Palala shear zone in the northeast. Palaeoplacer titanomagnetite-ilmenite-zircon heavy mineral deposits, best developed in the Cleremont Formation in the centre of the basin, reflect initial fluvial reworking and subsequent littoral marine concentration. Coarse alluvial cassiterite placer deposits are found in the Gatkop area in the southwest of the basin, and appear to have been derived from stanniferous Bushveld Complex lithologies south of the TML. Hydrothermal zinc and U-Cu mineralisation in the Alma lithologies in the same area appears to be related to the TML fault system. Small manganese deposits and anomalous tungsten values occur in the south of the basin, where they are again closely spatially associated with the TML. Copper-barium mineralisation is found associated with dolerite dykes, and in stratigraphically controlled, inferred syngenetic settings. The most interesting of these apparently syngenetic occurrences is found within green coloured reduced mudrocks and inferred volcanic rocks, at an unconformity developed within the overall red bed sequence of the Waterberg Group, adjacent to the TML in the southwest of the basin. The most important potential mineralisation in the main Waterberg basin thus encompasses shoreline placer Ti and the possibility of substantial sediment-hosted copper deposits. Received: 31 May 1996 / Accepted: 17 February 1997     

Microscopic charcoal in sediments: Quaternary fire history of the grassland and savanna regions in South Africa

The microscopic charcoal content of several Quaternary pollen sequences is used to investigate fire history in South Africa both during the Holocene and the Late Pleistocene. Although fluctuations in charcoal composition are recorded, it is difficult to link them directly to either human‐made or natural fires. Strong long‐term variations in microscopic charcoal of Middle and Upper Pleistocene layers are independent of pollen indications of past temperature and moisture conditions. Holocene charcoal sequences from different areas show no correlation, so no phases of regional burning are found. Some fluctuations in charcoal probably are the result of local burning in the various regions. The arrival of Iron Age people some 2000 yr ago apparently did not coincide with widespread wild fires, as these events do not consistently appear in regional microscopic charcoal records. The only exception appears to be the Wonderkrater spring deposit. Relatively open savanna environments, which are implied by pollen analysis at some sites during this period and the generally low microscopic charcoal contents, were either caused by climate change or controlled burning by Iron Age people. Copyright © 2002 John Wiley & Sons, Ltd.     

The Reitz ring: a possible circular structure, 350–500 km in diameter,in South Africa

The accurate northwestern rim of the upper Witwatersrand sedimentary basin in South Africa can be regarded as representing 120 degrees of an original circular structure roughly 400 km in diameter. Extrapolation of the perimeter passes, on the east and northeast, near to outcrops of the older, but lithologically similar, Mozaan Series. The center of this circle coincides with a positive Bouguer gravity anomaly, near Reitz (“Ray-tz”), South Africa. If these features are genetically related, the symmetry may reflect an early meteorite impact structure.     

The Role of non-timber forest products as safety-nets: A review of evidence with a focus on South Africa

Poor, rural communities are vulnerable to adversity. To secure their livelihoods, people adopt multiple livelihood strategies, including using non-timber forest products (NTFPs). NTFPs have been identified as important to rural livelihoods, as an alternative land-use option as well as in fulfilling an important safety-net function although empirical evidence on the latter’s strength is limited. Whilst NTFPs may contribute towards alleviating poverty, this safety-net function needs more critical and quantitative investigation. This includes the establishment of an applicable definition so this function can be communicated to policy makers and taken into account in national poverty alleviation strategies and, in attempts to promote resource-conserving behaviour by highlighting the value of natural resources (including NTFPs) compared to alternative land-use options. Poverty in rural households is complex and households are vulnerable to a range of shocks. During adversity households can turn to a range of possible safety-nets. What determines the use of NTFPs as a safety-net, how this safety-net function manifests and the strength of this function is poorly understood and there is need for further investigation.     

The Karoo Basin of South Africa: type basin for the coal-bearing deposits of southern Africa

The coal-bearing sediments and coal seams of the Karoo Basin, Southern Africa are described and discussed. The Karoo Basin is bounded on its southern margin by the Cape Fold Belt, onlaps onto the Kaapvaal Craton in the north and is classified as a foreland basin. Coal seams are present within the Early Permian Vryheid Formation and the Triassic Molteno Formation.The peats of the Vryheid Formation accumulated within swamps in a cool temperate climatic regime. Lower and upper delta plain, back-barrier and fluvial environments were associated with peat formation. Thick, laterally extensive coal seams have preferentially accumulated in fluvial environments. The coals are in general inertinite-rich and high in ash. However, increasing vitrinite and decreasing ash contents within seams occur from west to east across the coalfields. The Triassic Molteno coal seams accumulated with aerially restricted swamps in fluvial environments. These Molteno coals are thin, laterally impersistent, vitrinite-rich and shaly, and formed under a warm temperate climatic regime.Palaeoclimate, depositional systems, differential subsidence and basin tectonics influence to varying degrees, the maceral content, thickness and lateral extent of coal seams. However, the geographic position of peat-forming swamps within a foreland basin, coupled with basin tectonics and differential subsidence are envisaged as the primary controls on coal parameters. The Permian coals are situated in proximal positions on the passive margin of the foreland basin. Here, subsidence was limited which enhanced oxidation of organic matter and hence the formation of inertinitic coals. The coals in this tectonic setting are thick and laterally extensive. The Triassci coals are situated within the tectonically active foreland basin margin. Rapid subsidence and sedimentation rates occurred during peat formation which resulted in the preservation of thin, laterally impersistent, high ash, vitrinite-rich, shaly coals.     

The indigenous growth towards a cash economy in Africa — A case study of a lacustrine economy in Malawi

Chilwa, an endohreic lake in East Central Africa, lies in a basin peripheral to the developed areas of the Shire Highlands in Malawi. In 1965 the catch of fish accounted for half the estimated catch of Malawi, while the seasonally inundated grasslands sustain 35,000 head of cattle. The receding lake has left a series of terraces favourable to cotton and tobacco production. This study examines the responses of the people in the southern section of the plain to circumstances which could offer an integrated rural economy with the additional advantage of an entry into the money nexus through commercial fisheries.     

Environmental preferences for recreation within deprived areas: the case of black townships in South Africa

The urban black townships in South Africa differ from other deprived areas largely as a result of the circumstances under which they came into existence. The environmental preferences for recreation in these areas, hitherto uncharted territory, form the nucleus of this contribution. Comprehensive research has revealed the residents' specific environmental preferences for recreation. The most important aspect is the significance of the home as the recreational environment. Furthermore, evidence of the extensive utilization of informal recreational areas provides a new dimension to the inadequacy of the provision of facilities. The CHAID computer program, applied to certain demographic variables, was used to gain new insight into the factors that determine environmental preferences for recreation in deprived areas. The most significant of these appears to be the level of education, which could mean that a general increase in the level of education could result in an increased demand for recreational facilities. This analysis has revealed a number of important guidelines for planning.     

Textural evidence for quartz and feldspar dissolution as a mechanism of formation for Maggs Pipe,Zaaiplaats tin mine,South Africa

Shallowly plunging and branching pipe systems in Lease and Bobbejaankop Granite at the Zaaiplaats mine are host to major tin mineralization. Detailed textural study of Maggs Pipe indicates that dissolution of the granite was a major process in the formation of open space which provided permeability for the passage of hydrothermal fluids, and sites for the precipitation of ore and gangue minerals. The pipe formation process initiates with the dissolution of granite quartz and subsequently extends to feldspar dissolution, particularly in the central portion of Maggs Pipe. Spaces created by mineral dissolution are filled by hydrothermal phases and the relict feldspar matrix becomes progressively more altered toward the centre of the pipe. The distribution of alteration and infill minerals defines a zoning pattern which, from the outer margin to the central core, includes calcite-quartz, chlorite (± cassiterite, albite, fluorite) and synchisite-calcite zones. It is postulated that quartz and feldspar dissolution resulted from interaction between the granite and hydrothermal fluids containing alkali-chloride, -fluoride or -carbonate complexes which had separated from the granite magma during crystallization. Preliminary observations on several other pipes at Zaaiplaats indicate that quartz and feldspar dissolution was a major procress in forming the pipe systems.     

典型喀斯特岩性组合结构的流域水文干旱机制研究——以贵州省为例

水文干旱已成为全球气候变化背景下典型的自然现象, 是气象干旱和农业干旱的延续和发展, 是最终、最彻底的干旱.岩性是流域下垫面的重要组成物质, 其岩性类型及结构控制着地貌及水系的发育、促进流域储水空间的形成, 影响流域的储水能力, 关系到流域水文干旱的发生.本文在贵州省选择40个典型流域为研究样区, 利用面向对象分类技术, 提取流域岩性类型的遥感信息; 利用主成分分析及灰色理论, 研究岩性类型及其结构对流域水文干旱的影响机制.研究表明: 1)从岩性类型因素上看, 流域岩性类型对水文干旱影响总体较大, 影响从大到小排序(关联度)为: K(0.985) > Z(0.96) > O(0.924) > J(0.922) > S(0.806) > D(0.788) > ε(0.75) > C(0.69) > Pt(0.684) > P(0.568) > T(0.542); 2)岩性类型的主成分因素对流域水文干旱影响从大到小排序(关联度)为: Z3(0.48) > Z4(0.47) > Z1(0.44) > Z5(0.42) > Z2(0.39); 3)岩性类型组合方式对流域水文干旱影响从大到小排序为: Ⅰ、Ⅱ > Ⅴ、Ⅳ > Ⅲ.     

The evolution of a grospydite from the Roberts Victor mine,South Africa

A grospydite from Roberts Victor contains the most Ca-rich garnets yet found in South African kimberlite xenoliths and also sub-micron sized sodic nepheline in melted and quenched clinopyroxene. Three stages can be recognised in the textural evolution of the grospydite. The first is the development of a layering of large kyanite laths. Kyanite together with complex aluminous clinopyroxene precipitated and accumulated from an evolved residual eclogitic liquid which has penetrated across the garnet join so that garnet no longer precipitated. Solidus conditions for the Roberts Victor grospydite are estimated as T = 1350–1550 ° C, P = 27–39 kbars. Adjacent layers in the grospydite have slightly different mineral compositions suggesting that the small-scale layering (1–5 cm) in this, and associated rocks, may be related to varying activities of R₂O₃ components and possibly to f _{o 2}.The second stage is represented by a necklace texture in which all the garnet and some kyanite developed along grain boundaries of clinopyroxenes with triple-point textures. This is interpreted as an example of incoherent, grain-boundary exsolution resulting from large subsolidus volume changes. The conditions for subsolidus equilibration are estimated to be T= 1120–1320 ° C, P = 42–56 kbars.Moderate Ca-contents in garnet and excess Al^[6] in clinopyroxene may be subsolidus indicators of eclogite samples evolving towards grospydite at the solidus.The third stage is represented by the melting of jadeite-rich clinopyroxenes and quenching to glass, nepheline and plagioclase. Most of the glass has a composition similar to clinopyroxene, except for K₂O, though local areas of different glass, possibly the result of phase separation, also occur. The melting process seems to be a low-pressure feature involving limited addition of H₂O at temperatures between 900–1000 ° C. Water-absent melting could indicate temperatures up to 1500 ° C.The temperatures and pressures assigned to the three-stage evolution of this grospydite imply formation at moderate pressures and subsolidus equilibration at higher pressures. This is equated with downgoing mantle/asthenosphere tectonic processes. After entrainment in a kimberlite magma the grospydite fragment apparently ascended rapidly, thus allowing low-pressure melting and quenching.