Дисертації з теми "Dams Environmental aspects Thailand"

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.

The issue of water supply throughout the world is of concern for many reasons. It is projected that by the year 2025 two-thirds of the world's population will encounter moderate to severe water shortages. As a result of unsustainable development over the past decade, Thailand has faced pollution problems as well as the depletion of many natural resources. These problems have impacted on the country's main rivers (Chaopraya River, Thachine River, and the Bangpakong River), that are crucial to a sustainable economy, society, and culture. There needs to be a concentrated effort at all levels (individual to community) to address this problem. This thesis reports on a collaborative water conservation project undertaken in the Banmai and Bone market communities located on the banks of the Bangpakong River in Chachoengsao province, Thailand. In the first phase a qualitative research paradigm was used to gain an understanding of sixteen Bangpakong River stakeholders' perceptions of the river and to determine the factors motivating or constraining their water conservation behaviour. Information obtained in this phase was used to construct a questionnaire to measure a range of variables associated with water conservation behaviours and to provide a framework for the subsequent phases of the study. The second phase used the information accumulated in phase one and involved twenty community leaders in partial participant action research in order to obtain solutions for solving the water pollution problem, plan an appropriate Water Conservation Campaign and empower the leaders to mobilise community members. The third phase, the community-based Water Conservation Campaign planned by the community leaders in phase two was implemented over a six month period. Prior to the campaign, immediately following the campaign and three months after the completion of the campaign a sample of 110 community members completed a questionnaire designed to assess the effectiveness of the campaign and to determine the factors predicting their intention to conserve water. An additional 109 participants from Bang-Wua, and Bangkhla market community which was not involved in the campaign also completed the questionnaire as a control group. Multiple Regressions and repeated MANCOVA indicated that the Water Conservation Campaign had a significant effect on the participants in the experimental group across times in six aspects; namely Knowledge, Attitudes, Past Behaviour, Perceived Behaviour Control, Situational Supporters, and also the Intention to Conserve Water. However it did not have a significant effect on Subjective Norm or Sense of Community. With the exception of Situational Supporters, similar results were obtained when the leaders were excluded from the analysis. In comparison to the control group, the experimental group scored significantly higher on Water Conservation Knowledge, Intention to Conserve Water, Attitude towards Water Conservation, Subjective Norm, Past Behaviour, Perceived Behavioural Control and Situational Supporters immediately after the campaign. The same results were obtained when leaders were excluded from the analysis. However, three months later, the experimental group (with and without leaders) scored significantly higher only on Water Conservation Knowledge, Subjective Norm and Past Behaviour, and significantly lower on Situational Supporters. These results suggest that community involvement in a water conservation campaign is an effective, empowering and useful approach to address the issue of water pollution in the Bangpakong River.

Lastly, the study demonstrated that in order for hotels to become more sustainable, support is needed from government or hotel associations to provide education and training for the hotel managers.; This study explored the attitudes of hotel managers in Phuket, Thailand, in an attempt to identify whether their attitudes influence their utilization of environmental sustainability practices. Due to the increasing number of visitors to Phuket, Thailand, the consumption of natural resources has increased in the region, causing serious environmental problems. A sustainable way forward is needed for the tourism industry in the region in order to maintain quality of service while reducing environmental damage. The data analyzed in this study came from self-administered questionnaires that surveyed hotel managers in Phuket, Thailand, with a sample of 243 respondents. Research results revealed three dimensions of hotel manager attitude toward environmental sustainability practices, including operational management, social obligation, and sustainability strategy and policy. Furthermore, three constraints on the implementation of environmental management practices were identified: lack of support, perceived difficulty, and lack of demand. The attitudes of hotel managers regarding specific factors and barriers are also presented in this study. The results of this study show that hotel managers overall possess positive attitudes toward environmental sustainability practices. Finally, the findings reveal that hotel managers' attitudes toward sustainability practices depend on their social demographics, the type of hotel they operate, their degree of ownership of the hotel, whether or not their hotel was affected by the 2004 tsunami, and the year their hotel was built. The results of this study suggest that it is necessary for hotel managers to understand the importance of environmental sustainability practices because this understanding can help motivate them in implementing sustainability practices in their hotels. Furthermore, it can guide hotel managers when deciding which environmental policies are suitable for their hotels.
ID: 029810123; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 110-119).
M.S.
Masters
Rosen College of Hospitality Management
Hospitality and Tourism Management

The global hospitality industry is currently facing many challenges from the external business environment. These include the effects of global recession, a downturn in overall trade and an increased demand for service excellence from a much more quality conscious clientele. A more recent challenge, however, relates to an increase in global awareness of environmental issues. Contemporary consumers require goods and services to be produced, or delivered, in environmentally friendly ways. As a result, managers are being forced to reconsider their business strategies and activities. Indeed a wide range of industries has already responded to consumers' dictates on conservation issues. It is now universally accepted that organisations can only achieve their strategic objectives by adopting an environmentally friendly philosophy. The global hotel industry, like any other industry sector, can no longer resist this trend. This study, therefore, shall examine the extent of environmental management practice in the hotel industry, which is one of the major sectors responsible for the development of sustainable tourism. In particular, this study investigated the extent of Green Practice within the Phuket hotel industry, in Thailand. It reports the findings from a two-stage methodology that was designed to shed light on both the current extent of environmental practice within the Phuket hotel industry, as well as the motivation(s) for such practice. Empirical research is reported on a survey of Phuket hotels, with results suggesting that whilst there is evidence of environmentally sensitive practice within the Phuket hotel industry, this is not widespread and rather uncoordinated. The results further suggest low levels of environmental awareness amongst Phuket hoteliers and that where environmentally sensitive practices have been operationalised, this has been due more to the search for bottom line savings than any internalised believe in the value of any such practice.

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.

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.

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.

This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution. The study area included three provinces (namely, Kanchana Buri, Ratcha Buri, and Suphan Buri) located in the western part of central Thailand. Factors used for this purpose were soil texture, percent slope, primary land use, well depth, and monthly variance of rainfall. These factors were reclassified to a common scale showing potential to cause groundwater contamination by pesticides. This scale ranged from 5 to 1 which means high to low pollution potential. Also, each factor was assigned a weight indicating its influence on the movement of pesticides to groundwater. Well depth, the most important factor in this study, had the highest weight of 0.60 while each of the remaining factors had an equal weight of 0.10. These factors were superimposed by a method called “arithmetic overlay” to yield a composite vulnerability map of the study area. Maps showing relative vulnerability of groundwater to contamination by pesticides were produced. Each of them represented the degree of susceptibility of groundwater to be polluted by the following pesticides: 2,4-D, atrazine, carbofuran, dicofol, endosulfan, dieldrin & aldrin, endrin, heptachlor & heptachlor epoxide, total BHC, and total DDT. These maps were compared to groundwater quality data derived from actual observations. However, only the vulnerability maps of atrazine, endosulfan, total BHC, and heptachlor & heptachlor epoxide showed the best approximation to actual data. It was found that about 7 to 8%, 83 to 88% and 4.9 to 8.7% of the study area were highly, moderately, and lowly susceptible to pesticide pollution in groundwater, respectively. In this study a vulnerability model was developed, which is expressed as follow: V = 0.60CW + 0.10CS + 0.10CR + 0.10CL + 0.10CSL. Its function is to calculate a vulnerability score for a certain area. The factor “V” in the model represents the vulnerability score of a certain area, whereas CW, CS, CR, CL, and CSL represent the values or classes assigned to well depth, soil texture, monthly variance of rainfall, primary land use, and percent slope in that area.

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.

Thesis (MScAgric (Agricultural Economics))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: The rising demand of fish due to population growth coupled by stagnation of fish supply from natural capture has led the world to turn to aquaculture to fill in the gap between fish supply and demand. Aquaculture has emerged as the only sustainable way of supplying the rising population with fish. However the rapid expansion of aquaculture has been met with growing concerns over its environmental effects especially waste produced from aquaculture. The net cage system that is currently being used by small scale trout farmers in the Western Cape is an open water based system where release of waste into the water bodies is inevitable and this put into question the long term sustainability of trout farming using net cages in irrigation dams in the Western Cape. This study sought to compare identified production techniques that can be used by aquaculture farmers to reduce accumulation of organic waste in irrigation dams. The proposed ‘clean’ production techniques include use of net cages fitted with Lift-up system, semi intensive floating tank system (SIFTS) and intergrated aquaculture systems. The study revealed that the intergrated aquaculture system is the most effective way of recovering waste that shows great potential of moving aquaculture towards long term sustainability as it fullfills sustainability dimensions such as ‘zero emission’, nutrient recycling and integrated production. Mechanical methods of recovering waste such as Lift-up system and SIFTS are also effective in recovering particulate waste but however dissolved nutrients are lost into the environment. The study went on further to investigate if economic, environmental and social benefits of recovering waste from irrigation dams outweigh the costs of recovering waste using different production techniques. Models of small scale aquaculture farms using the three identified production techniques were developed and compared with a modelled small scale net cage farm where there was no waste recovery. A comparative financial analysis of the modelled small scale trout farms using alternative production techniques carried out showed that trout production using any of the three alternative ‘clean’ production techniques is financially viable with the SIFTS production technique giving the farmer the highest returns, followed by the intergrated system, then the net cage with a Lift-up system and lastly the net cage system without waste recovery. The second part of the study used the contingent valuation method to estimate the environmental and social benefits of removing waste from dams. Households revealed that they were willing to pay (WTP) R40 on average annually to improve water quality from a state where eutrophication had occurred to a state suitable for irrigation and aquaculture. To improve water quality from a state suitable for irrigation to a state suitable for swimming, households were willing to pay R16.67 annually. If water was to be improved from a state suitable for irrigation to a level suitable for domestic purposes, average willingness to pay (WTP) was R26.17 annually. WTP indicate that besides financial benefits associated with using ‘clean’ production techniques there are environmental and social benefits that will arise to the farm community using water from the irrigation dams.
AFRIKAANSE OPSOMMING: Die stygende vraag na vis as gevolg van bevolkingsgroei, tesame met die stagnering van die aanbod van vis vanaf natuurlike vangste het daartoe aanleiding gegee dat die oë van die wêreld op akwakultuur gerig is om die gaping in die voorsiening van vis te vul. Akwakultuur het ontwikkel as die enigste volhoubare manier om aan die groeiende vraag na vis te voldoen. Die vinnige uitbreiding van akwakultuur het egter toenemende besorgdheid in die nadelige omgewingsimpak, veral ten opsigte van akwakultuurafval, tot gevolg gehad. Die nethokstelsel wat tans deur kleinskaalse forelboere in die Wes-Kaap in oop watergebaseerde sisteme gebruik word en die vrystelling van afval in die wateromgewings wat onafwendbaar is, plaas ’n vraagteken oor die langtermyn volhoubaarheid van die nethokstelsel forelboerdery in besproeiingsdamme in die Wes- Kaap. Die studie het ten doel gehad om geïdentifiseerde produksiestelsels wat deur akwakultuurboere gebruik kan word om die akkummulasie van organiese afval in besproeiingsdamme te verminder, te vergelyk. Die voorgestelde “skoon” produksietegnieke sluit in nethokke wat aan ’n opligstelsel gekoppel word, ‘n semi-intensiewe drywende tenk- stelsel (“SIFTS system” in Engels) en ‘n geïntegreerde akwakultuurstelsel. Met hierdie studie is bevind dat die geïntegreerde stelsel die mees effektiewe manier is om afval te herwin en toon potensiaal om akwakultuur op ’n vohoubare pad te plaas aangesien dit aan die volhoubaarheidsdimensies van geen emissie, voedingstofherwinning en geïntegreerde produksie voldoen. Meganiese metodes van afvalherwinning soos die nethokopligstelsel en die SIFTS-stelsel is effektief in die herwinning van vastestofdeeltjies, maar opgeloste voedingstowwe word steeds in die omgewing vrygestel. Die studie het voorts ten doel gehad om te bepaal of die ekonomiese, omgewings- en sosiale voordele om afval uit besproeiingsdamme te herwin, groter is as die herwinningskoste van die verskillende produksietegnieke. Modelle van kleinskaalse akwakultuurplase wat die drie geïdentifiseerde produksiestelsels gebruik, is ontwikkel en aangewend om te vergelyk met ’n nethokstelsel waar geen afvalherwinning gedoen word nie. ’n Vergelykende finansiële ontleding van die gemodelleerde kleinskaalse forelboerderye met die verskillende produksietegnieke is gedoen en daar is bevind dat enige een van die drie “skoon” stelsels finansieel lewensvatbaar is, met die SIFTS-stelsel wat die hoogste vergoeding aan die boer bied, gevolg deur die geïntegreerde stelsel, dan die nethokke aan ’n opligstelsel en dan die nethokstelsel sonder afvalherwinning. Die tweede deel van die studie het van die voorwaardelike (“contingent”) waardasiemetode gebruik gemaak om die omgewings- en sosiale voordele om afval uit besproeiingsdamme te verwyder, te bepaal. Huishoudings het aangetoon dat hulle bereid sou wees om tot R40 per jaar te betaal om die waterkwaliteit te verbeter vanaf ’n toestand waar eutrifikasie plaasgevind het na ’n toestand waar die water vir besproeiing en akwakultuur geskik sou wees. Om die waterkwaliteit vanaf ’n toestand geskik vir besproeiing te verander na ’n toestand geskik om in te swem, sou huishoudings bereid wees om R16.67 per jaar te betaal. Indien water vanaf ’n toestand geskik vir besproeiing verander sou word na ’n toestand geskik vir huishoudelike gebruik, sou huishoudings gewillig wees om jaarliks R26.17 te betaal. Die “gewilligheid om te betaal” dui aan dat daar bo en behalwe die finansiële voordele om van “skoon” produksietegnieke gebruik te maak, ook omgewings- en sosiale voordele vir die plaasgemeenskap bestaan met die gebruik van die water uit die besproeiingsdamme.

The Chehalis River Basin is located in the southwest region of Washington State, originating in the Olympic Mountains and flowing to Grays Harbor and the Pacific Ocean. The Chehalis River is over 125 miles, exists within five counties, and flows through agricultural, residential, industrial, and forest land areas. Four major rivers discharge to the Chehalis River, as well as many smaller creeks, five wastewater treatment plants, and groundwater flows. Flooding is a major problem in the relatively flat areas surrounding the cities of Chehalis and Centralia, with severe consequences for property, safety and transportation. As a result, construction of a flood-control dam in the upper basin has been proposed. One major concern of constructing a dam is the potentially severe impacts to fish health and habitat. The Chehalis River has routinely violated water quality standards for primarily temperature and dissolved oxygen, and has had multiple water quality and Total Maximum Daily Load studies beginning in 1990. CE-QUAL-W2, a two-dimensional (longitudinal and vertical) hydrodynamic and water quality model, was used to simulate the Chehalis River, including free flowing river stretches and stratified (in summer) lake-like stretches. The goals of this research were to assess the flood retention structure's impacts to water quality, as well as river responses to potential climate change scenarios. In order to use the model to achieve these goals, calibration to field data for flow, temperature, and water quality constituents was performed. This involved developing meteorological data, riparian shading data, and flow, temperature, water quality records for all tributaries during the calibration period of January 1, 2013 to December 31, 2014. System cross-sectional geometry data were also required for the model grid. Because of the short travel time in the river, the model was sensitive to boundary condition data, wind speed, bathymetry, nutrient kinetics, and algae, epiphyton, and zooplankton kinetics. Future conditions showed predictions of warmer water temperatures and slight changes to water quality conditions on the river. As fish in the area prefer cooler water temperatures, this could pose a threat to fish health and habitat. Flood retention structures also showed impacts to river temperature and water quality. Structures with the purpose of flood retention only (only operating during times of flooding) gave model predictions for daily maximum temperature higher than structures that employed flood retention and flow augmentation (operating during all times of the year). This suggested the management of flow passage or retention by the dam is important for water quality on the river. As this research continues improvements will be made, particularly to temperature and water quality constituents. Additional data for the system would be beneficial to this process. Model predictions of temperature were sensitive to meteorological data, including cloud cover, which were largely estimated based on solar radiation. Additional meteorological data throughout the basin would be useful to temperature results. Temperature results were also sensitive to the model bathymetry, and additional investigations into segments widths and water depths may improve temperature predictions. Water quality constituent data were largely lacking for the system. Many estimation techniques and approximations were used for input water quality constituents for the model upstream boundary and tributaries when little or no data were available, introducing uncertainty to the model. It was not possible to calibrate pH to field data because alkalinity data were essentially unavailable. However, other constituents had good agreement between model predictions and field data, including dissolved oxygen, nitrates, total phosphorus, and total suspended solids.

Expanding anthropogenic development within the tropical forest biome is driving the loss of an irreplaceable global resource. Mega-diverse tropical forests are vital for regulating the global carbon cycle, and are essential for climate change mitigation. Today, over half of the world’s remaining tropical forest is degraded or regenerating secondary forest. Tropical forests are becoming increasingly fragmented through the expansion of agriculture and roads. Landscape-scale flooding of terrestrial habitats caused by dam construction is an emerging driver of habitat loss and fragmentation. Much attention has been paid to the long-term impacts of tropical forest fragmentation for biodiversity, ecosystem functioning, and carbon emissions. Most of our understanding of the impacts associated with habitat fragmentation originates from systems in which the habitat matrix surrounding remnant forest patches is another, albeit low quality, terrestrial habitat. However, dam-induced habitat fragmentation results in remnant terrestrial biological communities becoming isolated on islands within a water matrix. A water matrix presents the worst-case scenario for remnant habitat fragments. In Chapter 2 I synthesise the results of numerous studies reporting the responses of taxonomic groups to isolation on reservoir land-bridge islands, and uncover a globally-applicable pattern of extinction debt acting upon remnant biological communities on reservoir islands. All islands, regardless of taxonomic group, habitat type, or island area lose species as island isolation time increases. Moreover, I show that contrary to existing ecological theory, once terrestrial habitat becomes isolated within a water matrix, it is effectively too isolated for species losses to be buffered by metapopulation dynamics. Dam development is rapidly expanding in the largest remaining tract of intact tropical forest, the Amazon Basin. In Chapters 3 and 4 I study the Balbina mega-dam system in the central Brazilian Amazon. Here, I use detailed field inventories of trees and lianas on islands and in continuous mainland habitat to determine the impact of landscape-scale habitat fragmentation caused by reservoir creation on these taxonomic groups. I find that islands maintain tree communities at significantly lower densities, richness and diversity compared to continuous forest. Furthermore, tree communities on islands exhibit compositional divergence from those found in mainland continuous forest. Island tree assemblages are dominated by low-wood density species, and may be on a trajectory towards communities characteristic of early successional forests with reduced carbon storage capacity. In contrast, liana assemblages remain compositionally intact and are becoming increasingly dominant relative to trees. Thus, lianas appear robust to many of the negative impacts associated with landscape-scale habitat fragmentation. As insular tree communities continue to degrade through area- and edge-effects, lianas may become a key feature of this archipelagic landscape due to their competitive advantage over trees in disturbed forest habitats. Lianas significantly inhibit tree recruitment and carbon storage. Thus, findings from Chapters 3 and 4 provide strong evidence for additional, and currently unaccounted-for biodiversity and carbon impacts associated with tropical dams. As development of tropical forest regions increases, there is an urgent need to reconcile the need for resources with the need for ecosystem service provision, such as carbon storage, particularly as we attempt to mitigate the impacts of rising atmospheric carbon. Recent studies have shown that secondary tropical forests have the potential to rapidly uptake atmospheric carbon, and act as a powerful tool in climate change mitigation policy. Broad-scale estimates of secondary forest carbon uptake are currently based on above-ground biomass alone. In Chapter 5 I present carbon stock estimates of additional tropical forest carbon pools - soil and dead woody biomass - in secondary forests ranging from 40-120 years. I find that soil fertility (nitrogen concentration) is key in determining carbon storage in secondary forests, and that the stability of carbon stocks held in dead woody biomass increases with secondary forest stand age. I highlight the need to integrate detailed site-specific information into broad-scale predictive models of secondary tropical forest carbon sequestration. This thesis links ecological theory and landscape-scale field inventories, to provide new understanding of the long-term costs of tropical forest fragmentation for biodiversity conservation and carbon storage, and provides further evidence of the important role secondary tropical forests may play in carbon sequestration and climate change mitigation.

Pacific lamprey (Entosphenus tridentatus), an endemic species to the Columbia River Basin, U.S.A, has experienced staggering decreases in returns to spawning territories in recent decades. As lamprey are threatened severely by a lack of passage at mainstem dams, lamprey specific passage structures have been designed and constructed to address the problem. The Cascades Island Lamprey Passage Structure (LPS) at Bonneville Dam is the longest and steepest structure of its type, following the addition of an exit pipe which allows lampreys to travel from the tailrace of the dam to the forebay. The intent of this study was to assess lamprey use of the structure and whether the structure hinders lamprey migration to subsequent dams. The study was carried out during the 2013 migration season. The study used three different treatment groups of lampreys released on five dates spanning the migration season (n=75 lamprey). Two of these groups (n=50), with different tagging methods, were released directly into the LPS to assess passage success, travel time, and tagging effect. The third group (n=25) was released into the forebay to test whether the structure impedes migration upstream. Fish were monitored via receiver arrays on the LPS and at dams on the river system. Overall passage efficiency was 74% (37 of 50 used the CI LPS successfully). Mean travel time to navigate the structure was 12 h. Fish size had no significant effect on travel time in the LPS. Water temperature had a significant effect on travel time in the LPS. There was no statistically significant effect of tagging on passage efficiency or travel time. The groups that used the LPS performed slightly better migrating upstream to the next dam than the group that bypassed the structure, but the difference was not significant. The groups that used the LPS traveled to more subsequent dams upstream than did the group that bypassed the LPS. It can be concluded that lamprey passed the structure successfully. Temperature (proxy for seasonality) had an effect on travel time in the LPS; however fish size and tagging had no effect. The LPS does not affect the ability of migrating lampreys to continue migration to subsequent dams. Such findings have important implications for management of lamprey in the region.

Thesis (PhD (Conservation Ecology and Entomology))--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: Water storage in reservoirs forms an integral part of the agricultural landscape in the Western Cape Province, South Africa. A few large reservoirs serve primarily as a drinking and industrial water supply, while on private farms, small reservoirs provide irrigation water for the dry summer period. Protection of water quality to secure irrigation and drinking water quality, and the extension of water use efficiency are priority issues in the Western Cape. In the current study, the suitability of rainbow trout (Oncorhynchus mykiss) cage farming as a non-abstractive water use was investigated. The current study concentrated on the identification, and where possible quantification of aquaculture impacts, the identification of successful sites and a description of requirements in which net-cage aquaculture has none or a very low negative impact on water quality (e.g. <15 % change from previous water quality conditions for phosphorus concentrations). In order to study the effects of 5 t trout cage production units in reservoirs <15 ha in area, the general ecology of the irrigation reservoirs was assessed. Sixteen reservoirs without aquaculture production (reference reservoirs) were compared to 26 reservoirs with aquaculture production (production sites with varying production histories). Catchment characteristics were also monitored. Water from different depths (0 m, 2 m, 6 m and near bottom) was tested for physical and chemical qualities as well as nutrient concentrations. Phytoplankton and zooplankton biomass and species composition was monitored. In addition to the general phytoplankton findings, cyanophytes were evaluated for their contribution to algal taint problems that emerged at a number of production sites. Sediments were tested for total phosphorus content and phosphorus release capacity. Indicators and minimum conditions to avoid the most common production problems were formulated. In order to determine long-term production success, which prevents trophic level changes of reservoirs, a mass balance approach (nutrient budget) was employed to indicate the limits for nutrients that can be added. The phosphorus balance indicated long term trends for reservoirs with and without aquaculture. The detailed mass balance approach was compared to a “ready to use” carrying capacity model that estimated the maximum fish load each reservoir could support. The anthropological input of phosphorus into the reservoirs causes a decreasing water quality in the studied reservoirs and this development was also reported for lowland rivers. Twenty percent of the studied reservoirs are in a condition that could be an immediate threat to fish or water bird health (e.g. free ammonia concentrations and pH). Harmful algal blooms were not observed. Aquaculture production evoked changes in water chemistry and ecology in most of the studied reservoirs. Adverse effects of aquaculture sites versus non-aquaculture sites were: increased phytoplankton biomass and species shifts towards sizes >80 μm. The increased phytoplankton abundance influenced pH maxima to values >9 at mid-day. The high pH fluctuations were greatly influenced by the naturally low alkalinity and hence low calcium buffering capacity of Western Cape waters. The deoxygenation of the hypolimnion during stagnation (summer) occurred faster in reservoirs of certain character, greatly dependent on elevation and surface area, with consequent acidification of the hypolimnion, as well as ammonia and total phosphorus (TP) accumulation. In this context, a diversity of each reservoir with and without aquaculture production, with a similar ratio of undisturbed reservoirs to reservoirs with influence of e.g. agriculture, were compared to each other. When grouping the respective differences from the average reference reservoir (i.e. no trout production), a low impact on water quality was manifested at four sites (15 %) with <15 % increase of bottom TP and ammonia, while eight sites (31 %) showed medium effects (59 % mean increase), and a high impact was found at 54 % of the sites (312 % mean increase). In reservoirs without aquaculture, the extent of incoming phosphorus (which could represent an influence by runoff from agricultural land) was very high. However, in small reservoirs (<5 ha), these values were exceeded by the incoming phosphorus from aquaculture practices. In the case of small reservoirs where the carrying capacity was clearly surpassed, effects caused by aquaculture were severe and the assimilation of waste by the system was not possible (in extreme cases aquaculture waste delivered 60 to 90 % of all incoming phosphorus – two to nine times the phosphorus brought in by rivers and runoff). With regards to sediment, only indirect conclusions could be drawn. Aquaculture production increased hypolimnetic anoxia and the latter was shown to increase potential phosphorus release from sediments. This implies that not only will aquaculture increase the phosphorus concentration of surface waters directly, but it will also increase internal loading. The sedimentation rate was increased with cage aquaculture which affects a hypothesized area of approximately 0.2 to 1.0 ha depending on reservoir hydrology. The composition of the sediment increased organic components which can impact on sediment processes. It can be postulated that increased sedimentation of aquaculture waste and extended anoxic conditions impact on macrozoobenthos. Hydrological and nutrient mass exchange of the reservoirs indicated that no annual increase of phosphorus was achieved with low nutrient input (good inflowing water quality) or good water exchange (>5 times per year), and sometimes with extraction of hypolimnetic water during the stagnation period (summer). A model developed by Beveridge (1984) showed similar results to the mass balance approach and can therefore serve as a more ready model to determine suitable stocking rates. The small (man-made) reservoirs in the Western Cape are in a eutrophication process which far exceeds the speed of natural eutrophication (trophic states indicating highly eutrophic or hypertrophic conditions after approximately 10 to 20 years following construction of the reservoirs) and this process is triggered by agricultural practice (indicated by literature – not a subject of this study). However, it is concluded from the data of this study that trout-cage aquaculture duplicated the total phosphorus already present (independent of continuation of the projects, the phosphorus introduced was trapped in the closed systems the reservoirs represent) in only 1 to 2 years of production - which means a significant acceleration of the eutrophication process already in place. There are positive exceptions where trout-cage production is possible without negative effects. Careful site selection is the most important step in successful and sustainable trout production. No impact of aquaculture was recorded at four reservoirs (15 % of the investigated reservoirs) which shared the characteristics of good water exchange (>3 times per year) and a minimum surface area of 5 ha. Additionally, criteria that reduced the risk of algal taint included a minimum water depth of 6 to 7 m in a reservoir at its lowest water point (to avoid intermediate mixing during the stagnation period) as well as cold hypolimnetic conditions (<17 °C) to minimize cyanophyte cyst remobilization. Further improvement of food conversion ratio (feeding management) and feed quality are the next (after site selection) two most important components that determine if a reservoir can be utilised for cage production without any long-term changes. There is potential in advances in feed quality, feed management and waste collection systems. These measures (e.g. the cage size could be decreased to efficate feeding management) can increase the number of sustainable sites and achieve multiplication of water use without water quality deterioration.
AFRIKAANSE OPSOMMING: Die stoor van water in reservoirs vorm ‘n integrale deel van die landboulandskap in die Westelike Kaap gedeelte van Suid-Afrika. ‘n Aantal groter reservoirs voorsien primêr water primer vir drinkdoeleindes en vir aanwending deur industrieë, terwyl kleiner reservoirs op private plase gebruik word vir besproeiing gedurende die droë somerperiode. Die beskerming van die waterkwaliteit en die uitbreiding van watergebruik se doeltreffendheid, word bestempel as ‘n prioriteit vir die Wes-Kaap. In die huidige studie is die geskiktheid van forel hokkultuur as ‘n bykomende watergebruik, maar sonder waterverbruik, ondersoek. Die huidige studie fokus op die identifisering en waar moontlik die kwantifisering van die impak van akwakultuur op besproeiingsreservoirs; die identifisering van potensiële reservoirs vir akwakultuur; en die beskrywing van toestande waarin akwakultuur geen of ‘n baie lae negatiewe uitwerking op die waterkwaliteit (bv. < 15 % verandering vanaf oorspronklike waterkwaliteitstoestande vir fosforkonsentrasies) sal hê. Om die impak van 5 t forel hokproduksie eenhede in <15 ha reservoirs te bestudeer, is die algemene ekologie van die besproeiingsreservoirs bepaal. Watermonsters, geneem op verskillende dieptes (0, 2, 6 en naby die bodem), is getoets vir fisiese- en chemiese kwaliteit sowel as vir die nutriëntkonsentrasies. Die biomassa en spesiesamestelling van fitoplankton sowel as zooplankton is gemonitor. Sestien verwysingsreservoirs is vergelyk met 26 produksiereservoirs (met wisselende vlakke van produksiegeskiedenis). Die karakeristieke eienskappe van die opvangsgebied is ook gemonitor. Tesame met die algemene fitoplankton bevindinge, is blougroen alge ook geëvalueer vir hul bydrae tot algae besmettingsprobleme wat voorgekom het by ‘n aantal produksie persele. Sedimente is getoets vir die totale fosforinhoud en fosforvrystellingskapasiteit. Perseelseleksie is geidentifiseer as een van die mees belangrikste faktore vir suksesvolle hokproduksie. Indikatore en minimum toetstande wat vereis word om die mees algemene produksieprobleme te verhoed, is geformuleer. Om die langtermyn produksie sukses te bepaal, wat trophiese vlakke se verandering in die reservoirs verhoed, is ‘n massa balans benadering (nutriënt balans) gebruik. Die fosfor balans het langtermyn tendense aangetoon en in die geval van die produksie reservoirs, is die akwakultuurimpak gekwantifiseer. Die gedetaileerde massa balans benadering is vergelyk met ‘n “gereed om te gebruik” drakapasiteitsmodel wat die maksimum vis wat die reservoir kan onderhou, geskat het. Die antropogeniese toevoer van fosfor na die reservoirs veroorsaak ‘n afname in die waterkwaliteit van die reservoirs wat bestudeer is. Die verskynsel van ‘n afname in waterkwaliteit is ook vir verskeie laagliggende riviere geraporteer. Sowat 20 % van die besproeiingsreservoirs wat bestudeer is, is tans in ‘n toestand wat die onmiddelike gesondheid van vis en watervoëls kan bedreig. Skadelike algebbloei is nie waargeneem nie. Akwakultuurproduksie het negatiewe effekte getoon in ‘n aantal reservoirs. Die nadelige uitwerking van akwakultuur waar digthede te hoog was, is: toename in fitoplankton biomassa en spesiesverskuiwinge. Die toename in fitoplankton teenwoordigheid het die pH maxima beïnvloed tot waardes >9 teen 12 uur middag. Die hoë pH fluktuasies is grootliks beïnvloed deur die natuurlike lae alkaliniteit en gevolglike kalsium bufferkapasitiet van die Wes-Kaap se waterbronne. Die deoksiginasie van die hipolimnion gedurende stagnasie (somer) het vinniger plaasgevind in oorbelaaide reservoirs, met gevolglik ‘n versuring van die hipolymnion, sowel as die akkumelering van ammoniak en totale fosfor. In hierdie konteks word reservoirs met en sonder landbouproduksie, met ‘n gelyke verhouding van onversteurde reservoirs tot reservoirs wat deur landboubedrywighede beinvloed word, met mekaar vergelyk. By vier persele (15 %) is ‘n lae impak vasgestel (<15 % toename in bodem TF en ammoniak), terwyl agt persele (31 %) ‘n medium impak getoon het (59 % gemiddelde toename in bodem TF en ammoniak) en ‘n hoë impak is opgemerk by 54 % van die persele (31 % gemiddelde toename in bodem TF en ammoniak). In reservoirs sonder akwakultuur, was die omvang van fosforinvloeiing baie hoog en is moontlik veroorsaak deur die invloei van afloopwater uit omliggende landbougebiede. Alhoewel in klein reservoirs (<5 ha) was hierdie waardes oorskadu deur die invloeiing van fosfor deur akwakultuur praktyke.In die geval van klein reservoirs, waar die drakrag duidelik oorskry is, was die gevolge, soos veroorsaak deur akwakultuur ernstig, en die assimilasie van afval deur die sisteem nie moontlik nie. In die uiterste gevalle het akwakultuurafval 60 % - 90 % van alle inkomende fosfor gelewer - twee tot nege maal die fosfor wat deur riviere en afloopwater ingevloei het. Wat die sediment aanbetref, kon slegs indirekte gevolgtrekkings gevorm word. Akwakultuurproduksie het hipolimnetiese anoksia laat toeneem en die laasgenoemde verskynsel, het die potensiaal aangedui vir die toename in die vrystelling van fosfor vanaf die sediment. Dit dui daarop dat akwakultuur nie alleen die fosforkonsentrasie in die oppervlaktwater laat toeneem nie, maar sou ook die interne belading laat kon toeneem. Die sedimentasie tempo het toegeneem met die teenwoordigkeid hokkultuur en het ‘n hipotetiese area van ongeveer 0.05 tot 1.00 ha, afhangende van reservoir hidrologie, beïnvloed. Die samestelling van die sediment het toegeneem in teme van die organiese komponente wat die sedimentasie prosesse kon beïnvloed. Dit kan gepostuleer word dat die toename in sedimentasie van akwakultuurafvalprodukte tesame met verlengde anoksiese toestande, ‘n invloed op die makrosoöbentiese organismes het. Hidrologiese en nutriënt massa uitruiling van die reservoirs het aangetoon dat geen jaarlikse toename in fosfor verkry kan word met lae nutrient toelae (kwaliteit van invloeiende water) of met goeie waterverplasing nie, en soms met die ekstraksie van hipoliminetiese water gedurende die stagnasie periode (somer). Die Beveridge model het soortgelyke resultate getoon tot die massabalans benadering en kan daarom dien as ‘n meer aanvaarbare model om gepaste beladingstempo vas te stel. Kleiner mensgemaakte reservoirs in die Wes-Kaap is onderhewig aan ‘n eutrofikasie proses wat die spoed van natuurlike eutrofikasie (trofies verwys na ‘n hoogs eutrofiese of hipertrofiese toestand ongeveer 10 tot 20 jaar na reservoir konstruksie) oorskry. Literatuur (nie ondersoek in die huidige studie) dui aan dat hierdie versnelde eutrofikasie proses meegebring word deur landbouaktiwiteite in die opvangsarea van die reservoirs. Resultate van die huidige studie het getoon dat forelproduksie in hokstelsels, die konsentrasie van total fosfor wat reeds beskikbaar was, verdubbel het. Die toename in fosforkonsentrasie het binne 1 tot 2 jaar na die aanvang van forelproduksie in die betrokke reservoirs, plaasgevind. Daar is egter uitsonderings waar forelproduksie in hokstelsels moontlik was, sonder die gepaardgaande afname in die waterkwaliteit. Die belangrikste stap vir suksesvolle en volhoubare forelproduksie is deeglike perseelseleksie. Daar is geen impak van akwakultuur waargeneem by vier persele (15 %) wat die eienskappe van goeie waterverplasing (>3 keer per jaar) en ‘n minimum oppervlakarea van 5 ha gehad het nie. Bykomend, sluit kriteria wat die risiko van algbesmetting laat afneem, ‘n minimum waterdiepte van 6 tot 7 m in ‘n reservoir by die laagste punt in (om te verhoed dat intermediêre vermenging plaasvind gedurende die stagnasieperiode) sowel as koue hipolimnetiese toestande (<17 °C) om sianobakterieë sist remobilisasie te minimaliseer. Verdere verbetering van die VOH (voeromsettingsverhouding onder voedingsbestuur) en voerkwaliteit is na perseeleleksie, die volgende komponente wat kan aandui of ‘n perseel gebruik kan word vir hokkultuur sonder enige impak. Vordering met voerkwaliteit en voedingsbestuur kan die aantal volhoubare persele laat toeneem en daardeur meer effektiewe watergebruik teweeg bring, sonder die verwante waterkwaliteit verswakking.

Thesis (MScAgric (Conservation Ecology and Entomology)--University of Stellenbosch, 2007.
Small farm dams (< 20 ha) in the Western Cape Province provide adequate water conditions for intensive cage production of rainbow trout (Oncorhynchus mykiss). A major environmental concern of cage aquaculture, however, is the high inputs of nutrients via commercial diets and the subsequent eutrophication of the water source. Eutrophication can result in the degradation of the general water quality (increasing pH levels, oxygen depletion, increased hydrogen sulphide and free ammonia) and shifts in the phytoplankton structure (increased biomass, single species dominance). Deterioration of water quality will affect the success of the fish farming enterprise as well as the performance of irrigation equipment by increasing the risk of clogging and corrosion. Water quality, phytoplankton and zooplankton compositions were monitored at four sites from June 2005 to November 2006 to determine the effects of cage culture on the farm dam environment, its associated biota as well as irrigation water quality. The distribution of nutrients, nitrogen and phosphorus, was mainly influenced by the stratification and mixing regime of the water bodies. Nutrient concentrations increased during the winter mixing period while in the summer months, they seem to settle to the lower part of the water column. Nutrient concentrations of production sites and reference sites were comparable except for the ammonia levels that were significantly higher at the production sites. Phytoplankton corresponded with nutrient availability resulting in high biomass during winter. In terms of biomass, phytoplankton was approximately two times more abundant in production sites compared to reference sites. Assemblage dominance by cyanophytes (Anabaena circinalis, Microcystis spp.) was found more often in production sites, while reference sites were dominated by dinophytes (Ceratium hirundinella, Peridinium spp.). Zooplankton biomass concurred with high phytoplankton biomass in winter. Zooplankton assemblages in production sites sustained much higher biomass. Effects of cage culture on irrigation water quality are evident from increased algal biomass and shifts in species composition. These results indicated that at its present production level, cage culture had impacts on the farm dam environment and irrigation water quality. The most significant evidence was given by increased plankton biomass and single species dominance in production sites. However, these findings can not solely be ascribed to the introduction of aquaculture as various other factors may also contribute to the water quality of these ecosystems.

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

This thesis examines the role of district-level forest rangers in Northern Thailand. It builds an ethnographic case that Thai forest rangers have been largely successful in establishing with the local people their legitimacy to regulate the environment, but their effectiveness is limited by the influence of other stakeholders. The primary data that informs the thesis was collected during 15 months of living and working with a watershed management unit of the National Park, Wildlife and Plant Conservation Department. Other studies of Thai forestry often portray district-level foresters as part of a singular, uncompromising forestry bureaucracy. This thesis adds to literature on Thai state-society relations by illustrating how forestry regulation in Northern Thailand is profoundly influenced by local factors and by sometimes conflicting government interests. As the personal interface between the forestry department and village people, district-level foresters are in a unique position in the system of governance. They need professional expertise, political nous and social skills to carry out their department's conservation mandate while maintaining a welcome presence in the community. The thesis draws attention to how richly we can see the regulatory pluralism of Thai environmental governance by imagining it as a Thai dance of identities - the strategic interactions the rangers employ to achieve their ends. It highlights various sources of power and influence that district-level foresters have to consider as they tailor broad environmental management policies to a local situation. It notes that the public image of environmental protection projected by the department, and the reality on the ground, are not the same - the difference between them being influenced by Thai cultural norms. District-level foresters make effective use of their geographic isolation, their social embeddedness in local villages, and religious and political ceremonies to aid them in their regulatory task.

D.Phil.
Over a century gold exploration and extraction on the central Witwatersrand has left a legacy of mine residue deposits. Although there have been numerous complaints and claims of health effects associated with dust from these residue deposits, mostly these have been dismissed as mere nuisance. This study hypothesized that gold mine tailings on the Witwatersrand pose significant health risks to the nearby communities due to respirable airborne tailings material. Preliminary review of information on the tailings led to the insight that tailings source material and atmospheric properties at receptor sites are poorly characterized from the point of view of particle size-mass distributions. For years, routine monitoring of emissions from tailings storage facilities has been limited to sampling of dust fallout (settlable particles ≥ 30 μm). A suite of fifty four source samples (thirty-six slime, six newer slime and twelve sand) were collected from tailings storage facilities along the mining corridor covering deposits in the Carltonville area through to Springs. Size class characterization of source material was performed in the diameter range 0.05 μm to 900 μm using a Malvern® MS-14 Particle Analyser with 64 channels, from which the respirable (dp< 5 μm) and thoracic (dp < 10 μm) components were measured. Secondly, source materials were sieved (using a sieving cloth) in dp < 5 and < 10 μm fractions and the data derived was used in validating the size class results from the Malvern® MS-14 Particle Analyser before subjecting the samples to chemical analyses (elemental, mineralogical and radioactivity). Two years of continuous dust fall samples were collected in two different residential areas close to selected tailings storage facilities and subjected to similar size class characterization with the Malvern® MS-14 Particle Analyser. Further, continuous size-mass characterization of airborne aerosols was conducted in two different locations in the vicinity of tailings storage facilities with the Grimm® aerosol particle counter, in the diameter range 0.25 μm to 32 μm. The Grimm® aerosol particle counter was collocated with the MicroVol® PM10 filter sampler ambient monitor. The risk zones around selected tailings storage facilities were established by conducting dispersion modeling with American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD). The spatial evolution of tailings storage facilities and built-up areas is assessed using multiple aerial photographic images, covering four periods from 1952 to 2008. Overall, detailed spatial analysis was conducted and human inhabitants are now at greater risk than before. We have quantified the number of inhabitants living within the high-risk zone surrounding selected tailings storage facilities. The combined areas occupied by tailings storage facilities have increased from ~4 km2 (1952) to 10 km2 (2002); and residential areas ~4 km2 (1952) to 27 km2 (2002) within a buffer of 2 km. Population grew between 1952 and 2002 by a factor x29 at Crown Gold Recoveries; x43 at Durban Roodepoort Deep (from 1976); and x25 at East Rand Proprietary Mines.

褚涓.
"2010年9月".
"2010 nian 9 yue".
Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 99-106).
Abstract in Chinese and English.
Chu Juan.
論文摘要 --- p.i
Abstract --- p.ii
Chapter 第一章 --- 導論 --- p.1
Chapter 第一節 --- 研究背景與研究問題 --- p.1
Chapter 第二節 --- 理論文獻綜述 --- p.4
“碎片化的權威主義´ح與“多元化´ح --- p.5
中國環保NGO的政治闡釋 --- p.11
Chapter 第三節 --- 研究設計 --- p.16
研究對象 --- p.16
研究意義 --- p.17
資料收集 --- p.20
文章結構 --- p.20
Chapter 第二章 --- 水壩政治的制度環境變遷 --- p.21
Chapter 第一節 --- 水電體制改革：行動者與利益 --- p.23
水電管理與投資體制改革 --- p.23
水電的規劃與決策 --- p.26
Chapter 第二節 --- 官僚政治：環保總局分享決策權 --- p.29
環保總局的“升遷´ح之路 --- p.29
環評制衡水電開發 --- p.30
Chapter 第三節 --- 公民社會政治：環保NGO結緣江河開發 --- p.33
都江堰“保衛戰´ح --- p.34
漫灣電站社會影響評估 --- p.36
Chapter 第三章 --- “保留一條原始生態江´ؤ´ؤ怒江！ ´ح --- p.38
Chapter 第一節 --- 怒江水電開發政策議題的開端 --- p.38
怒江水電項目的由來 --- p.38
環保總局發力 --- p.40
Chapter 第二節 --- 環保NGO的初期動員 --- p.44
掀起媒體“風暴´ح --- p.44
遊說官員 --- p.47
尋求國際社會的支援 --- p.49
NGO之間的聯盟 --- p.S1
深入怒江考察和調研 --- p.52
通過兩會提案保護怒江 --- p.54
Chapter 第三節 --- 總理批示：“慎重研究、科學決策´ح --- p.55
政府内部的角力 --- p.55
爭論聲中叫停 --- p.57
Chapter 第四節 --- 社區行動與政府的反應 --- p.59
綠色流域走進社區 --- p.59
遭到打壓 --- p.62
Chapter 第四章 --- 新一輪的挑戰與動員 --- p.65
Chapter 第一節 --- 轉折：總理再次批示 --- p.65
“傳媒戰´ح受挫與院士考察團訪問怒江 --- p.65
地方政府遊說中央 --- p.67
Chapter 第二節 --- 環保NGO的第二輪動員 --- p.69
呼吁知情权与参与权 --- p.69
啟動法律工具 --- p.71
Chapter 第三節 --- 陷入膠著 --- p.72
官方的表態 --- p.72
環保NGO的後續倡導 --- p.75
Chapter 第四節 --- 虎跳峽、小南海電站再掀波瀾 --- p.77
Chapter 第五章 --- 結論：決策開放化的解讀 --- p.80
政府的“碎片化´ح與“權威´ح --- p.82
利益代表：有序的政治參與官僚包辦 --- p.85
公眾參與的“陷阱´ح --- p.92
參考文獻 --- p.99
附件：訪談對象 --- p.107

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.

In the Kingdom of Lesotho, large dams are currently being constructed with the sole purpose of selling water to the Republic of South Africa, in order to earn royalties and to generate electricity for Lesotho. The focus of this study was to investigate the perception of the community on the socio-environmental impacts of Metolong Dam and Reservoir in Lesotho. A qualitative research methodology was adopted and grounded theory was used in collecting data from the study area. Qualitative research techniques used were document analysis, field notes and semi-structured interviews. After conducting an audit which evaluated the accuracy of the initial Environmental Impact Assessment (EIA) by comparing actual to predict impacts, it was found that the perceptions of the community on the socio-economic impacts of Metolong project were: the community had poor education due to expensive school fees and their level of education did not help with dynamics on climate for they are complex and not easily to be understood, alcoholism existed due to unemployement, cultural constraints existed dominated by the patriarchal structures on the land and decision making, compensation policy was not honoured by project developers, the project brought benefits and loss of life-support resources, people are unable to grow wheat, beans and peas for their fields are taken and the community experienced loss of building sand that is not addressed. Information obtained helped the study to close the gap which appears not to have been addressed by the Government of Lesotho Department of Water Affairs Lowlands Water Supply Unit, 2008. Results of the study revealed that local villagers in the study area were happy with the project benefits, but they were discontented with the project as they were not incoporated in the management and supervision of the project. Rather, the local villagers were engaged only as labourers. The study recommends that when large dams are constructed, local villages should not be given promises that are dressed with many enticing commitments. The reason is that, communities never asked for the project, but it is set forth authoritatively as obligatory upon them. Project authorities should increase their efforts to fulfil promises made. Not only that, they should have respect, compassion, care and dedication when dealing with affected people. It is in this regard that the Local Based Project Execution and Observation Model is proposed, which will incorporate local villagers in the management steps of all large dam developments within their communities, in order to contend with environmental impacts of large dams.
Environmental Sciences
Ph. D. (Environmental Management)

Msc.
This study focuses on the functional evaluation of a gold Tailings Storage Facility (TSF), the Fleurhof TSF (designated slimes dam 2L3), which is representative of gold slimes (tailings) dams in the Witwatersrand. The aim is to evaluate the rehabilitation status (in terms of species composition and landscape function) of TSF surfaces that were planted ~20 to ~40 years ago using the most common rehabilitation practice, namely pasture grassing. Pasture grassing aims to obtain rapid dust control. Mine closure was not considered at the time, and the vegetation was hence not designed with ecological processes or long-term objectives in mind. However, over time, grassing practices became routine in the TSF vegetation industry, and the contribution that they have made towards surface rehabilitation needs to be assessed against the current site closure objectives. On the selected site, evaluations of vegetation cover, species composition, and substrate physical and chemical properties were conducted in 1975 (Thatcher, 1979). The aim of the current mid-summer study in 2009 was addressed by assessing the same parameters of vegetation cover, species composition, and soil physical and chemical properties, and comparing these to the results of the previous assessment in 1975. Landscape Function Analysis (LFA – an index-based method of evaluating the retention of resources by surfaces and soil condition), was applied to determine the landscape function (stability, infiltration and nutrient cycling that are derived from the eleven soil surface assessment indicators), and compared with the landscape function of natural analogues in the same locality. Landscape organisation (also an indicator of LFA) was used to investigate the contribution of vegetation overall, and of discrete plant functional groups to landscape functionality. A total of 35 plant species were observed in the quadrats (56 species on the TSF overall), with 51% of species overall being alien. Perennial vegetation and cryptogam covers contributed the most to stabilising the TSF slopes and flat (top) surfaces. The percentage of vegetation basal cover on the TSF (30% – 70%) was lower than for analogue grassland sites on a nearby hill (80% – 100%). Lower basal vegetation cover on the TSF than on the analogue site, were associated with lower LFA indices of stability on all TSF slope aspects (P = 8.19 x 10-13 for all aspects), iii lower nutrient cycling for the northern and southern TSF slopes (south aspect P = 4.20 x 10-6; top aspect P = 0.03), and lower infiltration on the southern slope of the TSF (P = 2.68 x 10-6). However, a higher infiltration on the northern TSF aspect (P = 0.02) than on the analogue site, was attained. Perennial tussock grass patch types (which included perennial forbs) made the largest contribution to the soil surface assessment (SSA) indicators on the TSF and analogue sites, and therefore to the LFA indices that were derived from these SSA indicators. The contribution of woody patches to function was not evaluated.

Graduation date: 2006
Dam removal is increasingly viewed as a river restoration tool because dams affect so many aspects of river hydrology, geomorphology, and ecology; but removal also has impacts. When a dam is removed, sediment accumulated over a dam’s lifetime may be transported downstream; and the timing, fate and consequences of this sediment remain some of the greatest unknowns associated with dam removal. In this thesis, I develop a conceptual model for erosion and deposition following removal of sediment-filled dams in mountain streams, and use field studies to document actual change. The data show that reservoir erosion in mountain rivers is likely to occur by knickpoint migration, with 85% of stored sediment being released during a single storm event in two field studies, at shear stresses less than that required for mobilization of the median surface particle size. Coarse sediment is predicted to deposit close to the dam with channel aggradation decreasing exponentially with increasing distance downstream, although some channel features are shown to have a greater propensity for aggradation than others. Field studies show that turbidity associated with dam removal and reservoir erosion may decrease hyporheic exchange, but gravel deposition (e.g., 470 m3 of gravel from Dinner Creek Dam) has the potential to more than offset that decrease, and increased hyporheic exchange is shown to reduce diurnal temperature change. Macroinvertebrate density and taxa richness did not respond to dam removal itself, but rather with time-lagged reservoir erosion. Following reservoir erosion, macroinvertebrate density recovered quickly, although longterm taxa community composition appears to be altered. On the Sandy River, field measurements of shear stress and patterns of sediment deposition following cold lahars were used as an analog to predict the fate of fine sediment, which is likely to deposit far from the dam. Results show that the Sandy River has little capacity for fine sediment storage in pools above RK 6.4 (~ 42 kilometers below Marmot Dam) at discharges associated with reservoir sediment releases. Taken as a whole, this paper illustrates a complex suite of process that may accompany removal of sediment-filled dams in mountain rivers.

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.

Thesis (M.A.(Development Studies))--University of the Witwatersrand, Faculty of Humanities, School of Social Sciences, 2016.
Public participation has become an integral component of development projects, and is encouraged in the South African constitution as well as national laws governing the development and management of the environment. Especially in large infrastructure projects such as dams and water transfer systems, community participation is essential, as these projects leave great social and environmental footprints, with the benefits often accruing far beyond the immediately affected areas. Yet, there is little consensus on how this participation should manifest or what it should hope to achieve. This study sought to examine public participation processes through a case study of a dam and pipeline project, the Mooi Mgeni Transfer Scheme Phase II, particularly in terms of its social impacts. The study draws from the perspectives of all stakeholders involved, namely the various project authorities (government architects, implementing company, engineers, construction contractors), the interested and affected community members, and the independent authorities hired to monitor different aspects of the project. This study found that differing views of participation among these different actors greatly affected the participation that manifested in the project. While project authorities’ primary focus for participation was as a means to achieve project goals, community members expected that participation directly benefit them, whether through mitigating impacts or maximising benefits. These differences are complicated by conflicting conceptions of participation in South African legislation, and scant conflict management mechanisms. These conflicting views of participation led to conflict in participatory spaces, and resistance against the project. This study examines five participatory spaces, namely Environmental Impact Assessment public participation meetings, Environmental Monitoring Committee meetings, the engagement with marginalised communities, the engagement with expropriated landowners, and the engagement with relocated informal farm workers. The analysis illuminates the way that power manifests in participatory spaces and can work for or against community goals, and also the effectiveness of different community strategies to leverage their interests. It finds that trust between project authorities and community members is often lacking, but can significantly reduce conflict when it is present. When conflict does arise, if community members are able to upset the project from proceeding, they can make significant inroads in achieving their interests. However, marginalised contingents of the community are faced with ingrained disempowerment in participatory spaces which is difficult to overcome
GR2017

The extensive reduction in adult Pacific lamprey (Entosphenus tridentatus) counts at many hydroelectric dams in the northwestern USA signals a substantial decline in lamprey numbers across the entire region in the past 40 to 50 years. Among the many potential causes of this decline, obstruction of migration routes has likely played a substantial role. Within the North Umpqua River basin in southwest Oregon, USA, I focused on the following three research goals: 1) to describe the passage efficiency and migration routes of adult Pacific lamprey at Winchester Dam; 2) to evaluate the seasonal movement patterns of adult Pacific lamprey and their use of holding habitat at Winchester Dam in relation to temperature conditions; and 3) to portray the diversity of upstream migratory behaviors of adult Pacific lamprey and the environmental factors that influence these behaviors. This radio telemetry study was conducted between March 2009 and August 2011 with a combination of fixed stations and manual tracking. Passage efficiency was low in both years (8% and 19%, respectively), and all tagged lamprey that successfully passed the dam used routes other than the fish ladder. Lamprey that migrated early within the run and those with relatively small tags had higher passage rates and traveled further than the other groups of lamprey. Lamprey released above of the dam or those that passed the dam on their own distributed themselves widely in the upstream environment, suggesting that the dam deterred their upstream migration. Using mark-recapture data for the two years, the adult Pacific lamprey population upstream of Winchester Dam was estimated at 960 (95% C.I. [188, 4760]) in 2009 and 556 (95% C.I. [110, 2798]) in 2010, which was considerably lower than historical counts at the dam (between 14,532-46,785 in 1965-1971). Most tagged lamprey that did not pass the dam remained at the base of the dam at the end of the summer migration (63% in 2009 and 67% in 2010). Types of habitat most frequently used by lamprey downstream from the dam included the dam surface (wooden structures with crevices), interface zones between fast and slow water, and highway bridge pilings. The lamprey movement changed considerably between August and September, and the frequency of movements decreased sharply during this period. Tagged lamprey were detected using thermal refuges immediately downstream of the dam that were 0.4 to 2.8 C° colder than the mean river temperature at the dam, and this temperature differential increased as the season progressed. Lamprey may be seeking overwintering habitat associated with hyporheic exchange flows at the dam towards the end of the summer season after their display of heightened activity early in the summer. Ninety-five percent of the overall upstream migration took place during the first spring/summer period, and only small-scale upstream movements were observed during the winter and second spring/summer (4% and 1%, respectively). The rate of upstream migration (median) was the fastest during the initial migration phase and was 1.9 km/day (ranging from 0.3 to 11.0 km/day) for tagged lamprey released above Winchester Dam. During winter, 71% of the lamprey remained in the same location where they initiated holding. Multiple regression analysis indicated that the total upstream distance traveled by individual lamprey was most strongly related to presence/absence of Winchester Dam, relative tag size, and water temperature and photoperiod conditions at release. The presence of Winchester Dam, large relative tag size, and high water temperature / short photoperiod conditions at release significantly reduced upstream migration distance.
Graduation date: 2012