The purpose of this study is to provide a description of the repercussions of hydro-dam development upon forestry in southeastern British Columbia. This study develops a systems viewpoint, where selected indicators - timber supply, access and transportation, forest land value, and reservoir clearing - are examined to help place land allocation decisions within a comprehensive framework. First, a timber supply model is developed, in which forest land withdrawal to hydro-dams is scrutinized. The model is then expanded to account for timber supply and demand relationships. Findings reveal that approximately 50,000 hectares of better than average sites were withdrawn from forest land, accounting for a reduction in timber supply of approximately 180,000 cubic meters annually. Second, changes in accessibility and transportation patterns due to hydro-dam projects are identified in terms of timber supply disruption, and strategies followed to re-establish forestry. Mica and Revelstoke dams are examined to show the importance of allocating economic resources to forestry for the maintenance of the activity. Third, forest land is evaluated in following the four methodological steps: (1) outline of a benefit-cost analysis framework, (2) definition of a general approach to evaluation, (3) description of B.C. Hydro's assessment, and (4) recommendations for improvement. The case of the Revelstoke Dam is examined, and it is concluded that resource development scenarios must take into consideration timber supply and demand factors. Fourth, reservoir clearing is described to outline an important aspect of short-term impact, and to express the way by which the Forest Service, B.C. Hydro and forest companies co-ordinated their efforts during this transition phase. The study concludes by suggesting that the impacts may be alleviated by initiating intensive forest management in areas affected by hydro-dam projects. The design of an effective system of timber allocation may also permit maintenance, and possible improvement, of accessibility and transportation patterns. However, the success of these actions depends upon the availability of sufficient funding. Finally, within a broader perspective, it is recommended that integrated resource management, as a control mechanism for land allocation and management, be adopted. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate

PhD / This study investigates how actions – especially narratives and claims – of civil society advocates influenced electricity generation planning and hydropower project implementation, in the context of a democratising authoritarian state. To pursue this research agenda, I use a critical realist philosophy of science to ground a conceptual framework whose fundamental components consist of institutions, interests, and discourses. The research presents three case studies from Thailand, a nation-state with distinct authoritarian legacies, as well as significant economic and political dynamism in the late 20th century. The cases step from macro to micro levels of analysis: (1) Electricity generation planning: an overview and critique of the social construction of peak power demand and supply options in Thailand, 1960s–2004. I focus on the rise of energy conservation advocacy in the early 1990s, and the rise of more confrontational energy activism in the late 1990s; (2) Pak Mun Dam: contention between EGAT, anti-dam villagers, and other state and civil society actors, 1989–2003; (3) Pak Mun Dam: analysis of how knowledge discourses shaped debates over fisheries and local livelihoods in the lower Mun river basin, 1999–2004. I pursue these cases in the larger context of Thai state–society relations, 1932–early 2000s: from the Khana Ratsadorn (People’s Party) and its founders’ increasingly authoritarian struggles to shape the state; through to the rise of civil society in the Indochina-war era; through the emergence of parliamentary politics and NGO evolution in the 1980s and early 1990s; to the Thai Rak Thai “money politics” party that emerged in 1998. Specific research questions focus on patterns and outcomes of state–society interaction, the role of lay and expert knowledge discourses in structuring conflict, and plausible causal connections between outcomes and concepts used in the conceptual framework. The study is based on fieldwork conducted between 2001 and 2005, with 18 months of intensive work concentrated in 2002 and 2004. Recurrent procedures consisted of collecting policy narratives and arguments and re-constructing actors’ interests (including those of leaders in organizations) via participant observation, interviews, and textual analysis. The thesis argues that anti-dam advocates influenced project implementation practices at Pak Mun Dam by forming social change networks, gaining contingent recognition as new political actors. Through innovative and disruptive action, through claims for transparency and justice, through mass performances of worthiness, unity, and commitment, and through the production of local knowledge, they helped set agendas. They triggered elite intervention, as well as reactive counter-mobilization and occasional violence. The escalation of uncertainty from unintended outcomes challenged elites – aided by deliberative exchanges – to reconsider unfavourable decisions, to reconsider their preferences, and to make concessions. At the same time, a number of events made the Assembly of the Poor, the main anti-dam movement organization, vulnerable to destabilizing action at the local and national levels. These include: the formation of competitive organizations in the lower Mun basin; complex and intractable issues (such as multiple rounds of compensation); and inability to take credit for championing the interests of vulnerable small farmers. Destabilizing interactions occurred particularly in the restricted media space of the post-financial and economic crisis years. Populist platforms put forward by Thai Rak Thai and Prime Minister Thaksin Shinawatra pre-empted the AOP’s influence. Sustainable energy advocates influenced practices of power system planning by teaching new techniques of energy conservation, and diffusing new norms. In the recent period, however, as some of them engaged in more contentious interaction, such as intervening in conflicts over new coal and hydroelectric power plants (in southern Thailand and Laos respectively) they disrupted dominant rationalities, and found themselves confronting some of the same core practices of a power-wielding bureaucracy and an authoritarian state, namely rhetorical strategies that police the boundaries of policy-relevant knowledge. The thesis, intended to contribute to social science methodology and theory, concludes with a critical appraisal of the conceptual framework. I suggest new research agendas for analysts interested in mechanisms of civil society advocacy in the context of democratising states.

PhD / This study investigates how actions – especially narratives and claims – of civil society advocates influenced electricity generation planning and hydropower project implementation, in the context of a democratising authoritarian state. To pursue this research agenda, I use a critical realist philosophy of science to ground a conceptual framework whose fundamental components consist of institutions, interests, and discourses. The research presents three case studies from Thailand, a nation-state with distinct authoritarian legacies, as well as significant economic and political dynamism in the late 20th century. The cases step from macro to micro levels of analysis: (1) Electricity generation planning: an overview and critique of the social construction of peak power demand and supply options in Thailand, 1960s–2004. I focus on the rise of energy conservation advocacy in the early 1990s, and the rise of more confrontational energy activism in the late 1990s; (2) Pak Mun Dam: contention between EGAT, anti-dam villagers, and other state and civil society actors, 1989–2003; (3) Pak Mun Dam: analysis of how knowledge discourses shaped debates over fisheries and local livelihoods in the lower Mun river basin, 1999–2004. I pursue these cases in the larger context of Thai state–society relations, 1932–early 2000s: from the Khana Ratsadorn (People’s Party) and its founders’ increasingly authoritarian struggles to shape the state; through to the rise of civil society in the Indochina-war era; through the emergence of parliamentary politics and NGO evolution in the 1980s and early 1990s; to the Thai Rak Thai “money politics” party that emerged in 1998. Specific research questions focus on patterns and outcomes of state–society interaction, the role of lay and expert knowledge discourses in structuring conflict, and plausible causal connections between outcomes and concepts used in the conceptual framework. The study is based on fieldwork conducted between 2001 and 2005, with 18 months of intensive work concentrated in 2002 and 2004. Recurrent procedures consisted of collecting policy narratives and arguments and re-constructing actors’ interests (including those of leaders in organizations) via participant observation, interviews, and textual analysis. The thesis argues that anti-dam advocates influenced project implementation practices at Pak Mun Dam by forming social change networks, gaining contingent recognition as new political actors. Through innovative and disruptive action, through claims for transparency and justice, through mass performances of worthiness, unity, and commitment, and through the production of local knowledge, they helped set agendas. They triggered elite intervention, as well as reactive counter-mobilization and occasional violence. The escalation of uncertainty from unintended outcomes challenged elites – aided by deliberative exchanges – to reconsider unfavourable decisions, to reconsider their preferences, and to make concessions. At the same time, a number of events made the Assembly of the Poor, the main anti-dam movement organization, vulnerable to destabilizing action at the local and national levels. These include: the formation of competitive organizations in the lower Mun basin; complex and intractable issues (such as multiple rounds of compensation); and inability to take credit for championing the interests of vulnerable small farmers. Destabilizing interactions occurred particularly in the restricted media space of the post-financial and economic crisis years. Populist platforms put forward by Thai Rak Thai and Prime Minister Thaksin Shinawatra pre-empted the AOP’s influence. Sustainable energy advocates influenced practices of power system planning by teaching new techniques of energy conservation, and diffusing new norms. In the recent period, however, as some of them engaged in more contentious interaction, such as intervening in conflicts over new coal and hydroelectric power plants (in southern Thailand and Laos respectively) they disrupted dominant rationalities, and found themselves confronting some of the same core practices of a power-wielding bureaucracy and an authoritarian state, namely rhetorical strategies that police the boundaries of policy-relevant knowledge. The thesis, intended to contribute to social science methodology and theory, concludes with a critical appraisal of the conceptual framework. I suggest new research agendas for analysts interested in mechanisms of civil society advocacy in the context of democratising states.

by Mo Pan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 150-160). / Table of Contents --- p.i / List of Tables --- p.vi / List of Figures --- p.viii / List of Plates --- p.viii / Abstract --- p.ix / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Background of the Three Gorges Dam Project --- p.1 / Chapter 1.2 --- Conceptual background of the study --- p.6 / Chapter 1.3 --- Objectives and significance --- p.16 / Chapter 1.4 --- Organization of the thesis --- p.18 / Chapter Chapter 2 --- Study Area and Experimental Design / Chapter 2.1 --- Zigui County --- p.20 / Chapter 2.2 --- Geology --- p.21 / Chapter 2.3 --- Climate --- p.22 / Chapter 2.4 --- Soil and vegetation --- p.22 / Chapter 2.5 --- Study area --- p.23 / Chapter 2.6 --- Experimental design --- p.26 / Chapter Chapter 3 --- Effect of Integrated Farming Practices on Soil Physical Properties / Chapter 3.1 --- Introduction --- p.30 / Chapter 3.2 --- Methodology --- p.32 / Chapter 3.2.1 --- Sampling methods --- p.32 / Chapter 3.2.2 --- Soil texture --- p.33 / Chapter 3.2.3 --- Aggregate stability --- p.33 / Chapter 3.2.4 --- Statistical analysis --- p.34 / Chapter 3.3 --- Results --- p.34 / Chapter 3.3.1 --- Effect of integrated farming practices on soil texture --- p.34 / Chapter 3.3.2 --- Effect of integrated farming practices on aggregate stability --- p.37 / Chapter 3.4 --- Discussion --- p.39 / Chapter 3.4.1 --- Soil textural change in relation to integrated farming practices and cultivation --- p.40 / Chapter 3.4.2 --- Aggregate stability of the newly rehabilitated soils --- p.43 / Chapter 3.5 --- Conclusion --- p.45 / Chapter Chapter 4 --- Effect of Integrated Farming Practices on Soil Chemical Properties / Chapter 4.1 --- Introduction --- p.46 / Chapter 4.2 --- Methodology --- p.48 / Chapter 4.2.1 --- Sample treatment --- p.48 / Chapter 4.2.2 --- Soil reaction --- p.49 / Chapter 4.2.3 --- Organic carbon --- p.49 / Chapter 4.2.4 --- Total Kjeldahl nitrogen (TKN) & available nitrogen (NH4-N and N03-N) --- p.50 / Chapter 4.2.5 --- Total and available phosphorus --- p.50 / Chapter 4.2.6 --- "Exchangeable K, Ca & Mg" --- p.51 / Chapter 4.3 --- Statistical Analysis --- p.51 / Chapter 4.4 --- Results --- p.52 / Chapter 4.4.1 --- Effects of integrated farming practices on soil reaction --- p.52 / Chapter 4.4.2 --- Effects of integrated farming practices on soil organic matter --- p.53 / Chapter 4.4.3 --- Effects of integrated farming practices on available nitrogen --- p.55 / Chapter 4.4.4 --- Effects of integrated farming practices on total Kjeldahl nitrogen (TKN) --- p.57 / Chapter 4.4.5 --- Effects of integrated farming practices on available phosphorus --- p.58 / Chapter 4.4.6 --- Effects of integrated farming practices on total phosphorus --- p.60 / Chapter 4.4.7 --- Effect of integrated farming practices on exchangeable potassium --- p.61 / Chapter 4.4.8 --- Effects of integrated farming practices on exchangeable calcium --- p.63 / Chapter 4.4.9 --- Effects of integrated farming practices on exchangeable magnesium --- p.65 / Chapter 4.5 --- Discussion --- p.66 / Chapter 4.5.1 --- The forgotten importance of pH --- p.67 / Chapter 4.5.2 --- The myth of soil organic matter --- p.70 / Chapter 4.5.3 --- Total Kjeldahl nitrogen and available nitrogen --- p.72 / Chapter 4.5.4 --- Total and available phosphorus --- p.77 / Chapter 4.5.5 --- The myth of exchangeable K and orchard growth --- p.78 / Chapter 4.5 --- Conclusion --- p.81 / Chapter Chapter 5 --- Effect of Integrated Farming Practices on Erosion / Chapter 5.1 --- Introduction --- p.84 / Chapter 5.2 --- Methodology --- p.90 / Chapter 5.2.1 --- Rainfall simulation --- p.90 / Chapter 5.2.2 --- Measurement of runoff and sediment --- p.92 / Chapter 5.2.3 --- Determination of soil volumtric moisture --- p.92 / Chapter 5.2.4 --- Statistical analysis --- p.93 / Chapter 5.3 --- Results --- p.93 / Chapter 5.3.1 --- "Effect of low intensity rainfall on time delay, duration, total runoff and mean discharge" --- p.93 / Chapter 5.3.2 --- "Effect of high intensity rainfall on time delay, duration, total runoff and mean discharge" --- p.95 / Chapter 5.3.3 --- "Effect of low intensity rainfall on sediment load, total soil loss and mean sediment loss rate" --- p.97 / Chapter 5.3.4 --- "Effect of high intensity rainfall on sediment load, total soil loss and mean sediment loss rate" --- p.98 / Chapter 5.3.5 --- Effect of hedgerow and farming practices on soil moisture under low intensity rainfall --- p.101 / Chapter 5.4 --- Discussion --- p.102 / Chapter 5.4.1 --- Effect of Vetivergrass hedgerow and integrated farming practices on runoff --- p.102 / Chapter 5.4.2 --- Effect of Vetivergrass hedgerow and integrated farming practices on soil loss --- p.106 / Chapter 5.4.3 --- Effect of Vetivergrass hedgerow and integrated farming practices on soil moisture --- p.110 / Chapter 5.5 --- Conclusion --- p.111 / Chapter Chapter 6 --- Crop Productivity: A Production Efficiency Analysis between Integrated Farming Practices and Existing Farming Systems in Zigui County / Chapter 6.1 --- Introduction --- p.113 / Chapter 6.2 --- Methodology --- p.115 / Chapter 6.2.1 --- Wheat and soybean production --- p.115 / Chapter 6.2.2 --- Socio-economic survey of agriculture in Zigui County --- p.116 / Chapter 6.2.3 --- Production efficiency analysis --- p.118 / Chapter 6.2.4 --- Statistical analysis --- p.119 / Chapter 6.3 --- Results --- p.119 / Chapter 6.3.1 --- Effect of integrated farming practices on wheat production --- p.119 / Chapter 6.3.2 --- Effect of integrated farming practices on soybean production --- p.120 / Chapter 6.3.3 --- Production efficiency of integrated farming systems (experimental plots) --- p.121 / Chapter 6.3.4 --- Production efficiency of existing systems (agricultural survey) --- p.122 / Chapter 6.5 --- Discussion --- p.124 / Chapter 6.5.1 --- Effect of integrated farming on wheat yield --- p.124 / Chapter 6.5.2 --- Effect of integrated treatments on soybean yield --- p.127 / Chapter 6.5.3 --- Will there be enough food production under integrated farming? --- p.129 / Chapter 6.5.4 --- Production efficiency analysis --- p.132 / Chapter 6.6 --- Conclusion --- p.136 / Chapter Chapter 7 --- Conclusion / Chapter 7.1 --- Summary of findings --- p.138 / Chapter 7.2 --- Implications of the study --- p.140 / Chapter 7.2.1 --- Demonstration farms and application of results to other parts of the TGR --- p.140 / Chapter 7.2.2 --- Commodity agriculture and regional specialization --- p.143 / Chapter 7.3 --- Limitation of the study --- p.145 / Chapter 7.4 --- Suggestion for further studies --- p.147 / Bibliography --- p.150 / Appendix A --- p.161

Thesis (MEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: A dam can have a significant impact on the downstream river morphology by altering both the flow regime and the sediment load. The effect of a dam is dependent on factors such as the storage capacity relative to the mean annual runoff (MAR), the operation of the reservoir and the sediment yield of the catchment. Changes in the river morphology include the degradation and coarsening of the riverbed, generally closer to the dam, and aggradation further downstream where the sediment delivered by tributaries cannot be carried through because of the reduced sediment transport capacity of the river. The impact of a dam can stretch over several hundreds of kilometres. The main objective of this thesis was to gain a better understanding of the impacts that dams can have on the downstream river morphology. This was done by developing equations that can describe the channel geometry, investigating the effect of the presence of clay and silt on the sediment transport behaviour of sediments, as well as detailed evaluation of simulations carried out with a one-dimensional mathematical river model (MIKE 11). The calibrated regime equations were found to be comparable to other internationally developed regime equations and to be suitable for natural rivers. It was found, however, that these regime equations are not applicable to rivers downstream of dams that have highly unnatural release patterns. Further research is needed in this regard. By investigating the effect of cohesive sediments on the sediment transport behaviour of mixed sediments it was found that as little as 7% clay and silt in the bed could affect their sediment transport characteristics. A methodology was also developed by which the critical conditions for mass erosion of cohesive sediments can be described in terms of the applied stream power. Sediment transport equations were calibrated and verified in terms of the unit input stream power for fine and non-cohesivesediments. The sediment transport equation for fine sediments was implemented in MIKE 11. The simulations over a 40 km reach of the Pongola River downstream of Pongolapoort Dam, have shown that even when a large demand is placed on the stored water, and most of the smaller floods are therefore absorbed by the dam, the downstream impact can still be considerable, with as much as 5 m deep erosion in places. The sediment loads are generally reduced (by as much as 35%), but the effective catchment area downstream of the dam has been reduced by as much as 90%, indicating that substantial erosion had to have taken place in the river. Coarsening of the riverbed was also observed during the simulations. / AFRIKAANSE OPSOMMING: 'n Dam kan 'n aansienlike impak he op die riviermorfologie stroomaf daarvan, deurdat dit beide die vloei en sedimentlading drasties kan verander. Die effek van 'n dam hang van verskeie faktore af, soos die opgaarkapasiteit in vergelyking met die gemiddelde jaarlikse afloop (GJA), die bestuur van die dam en die sedimentlewering van die opvanggebied. Veranderings in die riviermorfologie behels die degradering van die rivierbed, sowel as die uitspoel van fyn materiaal uit die rivierbed, veral nader aan die dam. Deponering vind verder stroomaf van die dam plaas, waar die sediment wat deur die sytakke ingevoer word nie deurgevoer kan word nie, weens die verlaagde sedimentdravermoe van die rivier. Sodoende kan rivierlope oor honderde kilometers deur 'n dam bemvloed word. Die hoofdoel van die tesis was om meer insig te verkry oor die impak wat damme op die stroomaf riviermorfologie kan he. Derhalwe is vergelykings ontwikkel wat die riviermorfologie kan beskryf. Die effek van die teenwoordigheid van klei en slik op die sedimentvervoer-eienskappe is ondersoek, en gedetaileerde ontledings is met 'n een-dimensionele wiskundige riviermodel (MIKE 11) is gedoen. Daar is bevind dat die regime-formules goed vergelyk met ander intemasionaalontwikkelde formules en dat hulle geskik is vir toepassing op natuurlike riviere. Daar is egter gevind dat die formules nie geskik is vir riviere wat stroomaf Ie van damme wat hoogs onnatuurlike loslatings het nie. Verdere navorsing is op hierdie gebied nodig. Ondersoek na die effek wat klei en slik op die sedimentdravermoe het, het getoon dat slegs 7% klei en slik in die rivierbed die sedimentvervoer-eienskappe van mengsels van fyn en growwe materiaal kan bemvloed. 'n Metode is ontwikkel waarmee die kritiese toestande vir massa-erosie van kohesiewe sediment beskryfkan word in terme van die aangewende stroomdrywing teen die bed. 'n Sedimentvervoer-vergelyking in terme van die eenheids-insetstroomdrywing vir fyn en nie-kohesiewe sedimente is gekalibreer en geverifieer. Die nuwe sedimentvervoer-vergelyking vir fyn sedimente is gebruik in die MIKE 11 simulasies. Hierdie simulasies oor 'n 40 km loop van die Pongolarivier stroomaf van Pongolapoort Dam, het getoon dat selfs as daar 'n groot aanvraag op 'n dam se water geplaas word, en gevolglik meeste van die kleiner vloede deur die dam geabsorbeer word, die impak van die dam nogs steeds aansienlik kan wees, met soveel as 5 m diep uitskuring in plekke. Die sedimentladings het gewoonlik verminder (met soveel as 35%), maar die die effektiewe opvanggebiedarea stroomafvan die dam het met meer as 90% verminder, wat daarop dui dat daar aansienlike erodering in die rivier plaasgevind het. Die simulasies het ook getoon dat die hoeveelheid fyn materiaal in die rivierbed verminder het.

Mining activity is suspected of contributing sulfate and total dissolved solids (TDS) to ground water downgradient of the Pima mining district. High ionic concentrations in tailing impoundments suggest that tailings-pond recharge may be a source of the contamination. Experiments indicated that sulfate is not significantly produced by inorganic sulfide oxidation in the tailings ponds. Tailings pond water chemistries were compared with historical water quality analyses in the Pima district. The U.S.G.S. computer program PHREEQE modeled saturation indices for anhydrite, calcite, fluorite, and gypsum in water chemistries throughout the study area. Well water downgradient of the mines had lower saturation indices than tailings pond water which discredits the claim that tailings-pond recharge is acquiring salts as it percolates to the aquifer. Evidence supports the opinion that tailings pond seepage is contributing to the sulfate and TDS content in ground water downgradient of the ponds.

There is a paucity of information concerning the invertebrate food resources available to juvenile salmonids in the Columbia River as they migrate seaward. Construction of mainstream dams has altered the temperature cycle, flow regime, and substrate which indigenous invertebrates were adapted to. Studies on how the macroinvertebrate community has adapted to these alterations have been neglected. This study was undertaken to help fill this void. Macroinvertebrate drift samples were collected over a three year period in the Columbia . River downstream from Bonneville Dam. Samples were collected with a D-ring plankton net fished on the bottom for one-half hour. Two sites were sampled; Ives Island (RKM 230), from 1987 through 1989, and Lady Island (RKM 193), in 1988 and 1989.

M.Sc. (Geography) / Severe Aeolian deposition of windblown dust from mine tailings storage facilities (TSFs) is a common phenomenon on the Witwatersrand, especially during the spring windy season. For communities around tailings storage facilities, this poses health and environmental challenges. This dissertation estimates the risk of adverse health effects resulting from human exposure to hazardous elements in particulate matter (sub 20 μm diameter) for selected tailings storage facilities: East Rand Gold and Uranium Company (ERGO); East Rand Proprietary Mine (ERPM); Crown Gold Recoveries (CGR) and Durban Roodepoort Deep (DRD). Samples of surface material from these TSFs were analysed for heavy metal content using the ICP-MS method. Other than the expected gold, five heavy metals (arsenic, cadmium, chromium, lead and uranium) exhibited enrichments in the tailings material significantly above average (greater than a factor of 2) crustal composition. These elements were selected for comprehensive risk assessment through airborne exposure routes. The mean ambient particulate concentration in air of 540 μg m-3 (used in the risk calculations) was based on a conservative worst-case exposure scenario. U.S. Environmental Protection Agency (US EPA) risk assessment methods were used to determine the inhalation and ingestion hazard quotient and hazard indices for adults and children. The sum of the hazard indices was below the non-cancer benchmark (hazard indices 1.0) considered to be acceptable for a lifetime exposure. The risk cancer included the excess life cancer risk for the inhalation and the ingestion risk. The total risk for both exposures was within the range of 1 in 1 000 000 to 100 in 1 000 000 - taken as “acceptable risk” by the U.S. Environmental Protection Agency for adults and children.

A comparative study was made of environmental variables and the density, biomass, diversity, and species composition of macroinvertebrates in areas downstream from a dam with a hypolimnetic release (Hungry Horse Dam on the Flathead River) and a dam with a selective withdrawal system (Libby Dam on the Kootenai River). A major objective of this study was to examine the response of macroinvertebrate communities to defined environmental gradients in temperature, flow, substrate, and food-related variables (periphyton, particulate organic carbon in the seston). In addition, the effects of experimental manipulations in discharge on macroinvertebrate drift and stranding were assessed, and the effects of temperature on the growth rates and emergence of five species of insects were measured.

M.Sc. (Geography) / Gold mine tailings deposits in the Witwatersrand are subjected to intensive wind and water erosion the combination of factors responsible for air and water pollution. Numerous efforts to alleviate this problem through vegetation have succeeded in establishing soil cover, although the surviving species are not representative of original indigenous vegetation and longer-term soil establishment has been poor. Contributing to these difficult conditions for establishing stable soil and plant communities are: low pH values; low surface stability; deficient organic matter and nitrogen; and high levels of heavy metal in the tailings. Although the role of cryptogams on nutrient cycling and positive impacts on growth of plants is well documented, their potential use in the planning of rehabilitation programmes of gold mine tailings has not been explored. In this study, the abundance and diversity of cryptogams and their impact on the chemical properties of Tailings Storage Facilities (TSF) surface material were investigated on three selected tailings dams: Fleurhof (2L3), Rand Leases (2L8), and Durban Roodepoort Deep DRD (2L24). On the third TSF, DRD (2L24), the original vegetation on the northern half has been entirely covered by wind- eroded material from the southern half the current surface represents a fresh un-vegetated surface. Field investigation was conducted to determine the abundance, diversity and coverage of cryptogams and their effect on the surface stability of the selected tailings. Bacteria, cyanobacteria and fungi were isolated and identified to evaluate the diversity and abundance of these organisms in the study area. In addition, electron microscopy observations were performed to understand the formation of the TSF crust. Chemical analyses of pH, electrical conductivity and the nutritional level of cryptogams TSF material were conducted to determine the effects of cryptogams on the chemical properties of the TSF material and predict the suitability of the substrate for the establishment of other microbes and vegetation. Abundant cryptogams, with diversified growth and morphological features, were found within the sampled areas. The cryptogam diversity proved similar to those across the three tailings dams, and was dominated by mosses and lichens. The abundance and growth of these mosses and lichens was dependent on the presence of vegetative cover and the direction of solar radiation. On undisturbed sites, cryptogams covered as much as 30% on DRD, 70% on RL, and 80% on FL. It was observed that the TSF surfaces covered by cryptogams were more stable than the bare ones. Ten genera of cyanobacteria were isolated from samples for the three tailings and identified, based on their morphology and growth characteristics, as: Aphanocapsa sp., Chromonas sp., Chroococcus sp., Cyanothece sp., Microcystis aeruginosa; Microcoleus sp., Nostoc sp., Oscillatoria sp, Scytonema sp. and Stigonema sp. Five fungal (Trichoderma gamsii, Phoma sp., Hypocrea lixii, Lecythophora sp, and Ascomycota) and four bacterial species (Bacillus subtilis, Arthrobacter aurescens, A. histidinolovorans, and A. sulfonivorans), representing the most abundant isolates from each group, iv were identified using DNA sequencing. Under the electron microscope, it was observed that the cryptogams being examined constituted diversified groups of organisms. Mycelia mats and sheathe produced by filamentous cyanobacteria and fungi played a major role in the formation of the crust by binding the TSF particles. The substrate had very low pH, EC, organic matter and nutrients essential for plant growth. However, the presence of cryptogams altered the acidity of the surface material into almost neutral and significantly improved the level of the essential nutrients and organic matter. It was concluded that the diversity of cryptogams in the TSF material was comparable to the diversity reported on other (different) soils. In addition, the cryptogams’ role in ameliorating the chemical properties of the surface material of the TSF is a clear indication that these organisms can play a positive role in stabilising the tailings material surface and promoting the growth of other microbes and higher plant forms.