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ASIA 2008 debates achievements and challenges for water resources development in Asia and the Pacific region High level delegations from 40 countries met at ASIA 2008 in Danang, Vietnam, to discuss all issues of relevance to the region with respect to developing water and renewable energy schemes. Deputy PM underlines Vietnam’s commitment to WRD and hydro Introduction of ASIA 2008 In her welcome address, AquaMedia Director Alison Bartle set the scene for the various sessions by drawing attention to some of the major issues in the Asian region. She looked at the vast amount of development under way in the host country, Vietnam, and other nations in the region, and felt that it was important to bring together representatives of countries at very different stages of their development programmes, for a constructive exchange of experience. She showed some statistics for world hydro development, and corresponding figures for the Asian region, which demonstrated that 84 per cent of the hydropower capacity under construction at present is in Asia (> 126 GW), and that a further 220 GW of hydro capacity is planned. She presented some of the current major projects and achievements of countries such as China, India, Russia, Vietnam and Lao PDR. She also pointed out that as well as setting records for achievements, the Asian countries also set less positive world records, in terms of vulnerability to natural disasters – floods, earthquakes, tsunamis, droughts, and so on. Water related disasters had caused around 600,000 casualties between 1960 and 2006, she said. She also spoke of future challenges for irrigation, with the need for food production to more than double by mid-century. More detailed information about the hydro development plans in Vietnam were given by Dr Lam Du Son, Vice President of EVN, in his opening address. Hydro currently provides about 36 per cent of electricity in the country; increasing demand would be met by increased domestic production, expansion of the national grid, and imports from neighbouring China, Lao PDR and w w w .v nc H.E. Hoang Trung Hai, Vice Prime Minister of Vietnam, inaugurated the event, and gave an opening address in which he underlined his Government’s commitment to water resources development. He pointed out that Vietnam’s water resources were extremely unevenly distributed in both space and time, with 80 per cent of precipitation falling within just two months, causing major flooding in some regions, and severe droughts during the dry season. He also reminded participants that Vietnam had only exploited about 20 per cent of its hydroelectric potential, and it was clear that hydro had a major role to play over the next 20 years. The Deputy Prime Minister participated throughout the first morning of the Symposium, listening to the keynote addresses, and then touring the ASIA 2008 Exhibition, where he discussed various technical innovations with the exhibiting companies. Above left, His Excellency Mr Hoang Trung Hai, Deputy Prime Minister of Vietnam, giving his opening address; right, Prof Pham Hong Giang, President of VNCOLD. ol d. early 500 participants representing 40 countries assembled in Danang, Vietnam, for ASIA 2008 – the Second International Symposium on Water Resources and Renewable Energy Development in Asia. This represented a much larger gathering compared with ASIA 2006 in Bangkok, indicating the increasing interest and activities in the water and energy sectors in this part of the world. The event was organized by Hydropower & Dams (Aqua-Media International), and co-hosted by Electricity of Vietnam. Strong support was also given by Vietnam’s Ministry of Agriculture and Rural Development (with the Vice Minister present), and the Vietnamese National Committee on Large Dams. vn N General view of the ASIA 2008 audience in Danang. 32 EVN Vice President, Dr Lam Du Son, describes Vietnam’s plans for hydro development. Cambodia. He pointed out that Vietnam has a total hydro potential of 18,000 MW, of which only about 4500 MW had been exploited. Projects under construction would provide an additional 5000 MW by 2010. He added that a total of 27 hydro projects were to be completed by 2015. He gave details of the schemes planned, by river basin. Keynote addresses This session was co-chaired by C.V.J. Varma, President of CPU, of India, and Dr Lam Du Son of EVN. VNCOLD President Prof Pham Hong Giang gave a keynote address in the opening session, in which he described the country’s dam development strategy; he explained dams played a key role in Vietnam’s socioeconomic development. The country has a humid sub-tropical monsoon climate, he said, with high annual rainfall (especially in the north and centre), and various mountainous areas, which provided excellent potential for hydropower development. He noted that there were many large dams currently under construction, and others planned for the near future. Various technical challenges included complex natural conditions, weak foundations, river bank eroHydropower & Dams Issue Two, 2008 Prof Luis Berga, President of ICOLD, who discussed the role of dams in sustainable development, in his keynote address. ICID President Peter Lee, who called for a policy to address rural needs, while developing a productive commercial sector. sion, sedimentation and environmental protection, he said. High level delegations were present from all Asian countries with major development programmes under way, including China, Lao PDR, Cambodia, Indonesia, Malaysia, Myanmar, Russian Federation, India, Pakistan and Nepal. More than 130 participants from Vietnam were present. ICOLD President Prof Luis Berga underlined the important role of dams worldwide, to meet a variety of human needs, and he pointed out the clear links between water infra-structure and various socio-economic development indicators. He stressed the need for a holistic approach to dam construction, taking all possible options into account at the planning stage. He also recommended the policy of integrated water resources management. He concluded that the key priority with respect to water resources development was poverty alleviation, and he underlined the importance of using and re-using water efficiently. ICID President Mr Peter Lee discussed development and productive objectives of agriculture, discussing the challenges of making different objectives compatible. He questioned, for example, how agriculture could continue to be one of the principle pathways out of poverty for the rural poor, ensuring food security at local village level, while at the same time producing enough food for cities, and ensuring national and global food security. Given that food supplies were predicted to need to increase by nearly 70 per cent over the next 30 years, he felt another ‘green revolution’ would be required to serve the needs and aspirations of the rapidly increasing world population. Future steps, Lee suggested, could include consolidating farm units, and improving connections to markets, as well as assisting farmers to bear costs and generate revenues to invest in improved techniques, as well as dealing with variability in both weather and market conditions. Lee concluded that a dual policy was necessary at present: investment should, on the one hand, be aimed at eliminating rural poverty and hunger, while on the other hand (as far as human and environmental needs would allow), developing a highly productive commercial sector. A keynote address on revisiting the concept of sustainable water infrastructure in Asia and the Pacific was given by Le Huu Ti, Chief of the Sustainable Development and Water Resources Section of UNESCAP. He noted that investment in water infrastructure in Asia and the Pacific region was now facing major challenges emerging from the complex socio-economic conditions of the region, the requirement for much higher annual investment, the urgent need to protect the environment, and the emerging challenges of climate change. He summarized some recent experiences relating to the concept of sustainable development, with special reference to the ‘Green Growth’ approach of UNESCAP, and he also stressed the value of regional collaboration, aimed at inclusive socio-economic development in the context of water infrastructure. Climate change was the subject of a special debate later in the day, when various diverging viewpoints were presented on the status of current research, but there was a consensus on the need for action in relation to water infrastructure. finance, powerplant design and operation, managing floods, earthquakes and sedimentation problems, and various aspects of civil engineering, including challenges site conditions. The following are summaries of the 12 sessions of ASIA 2008, which have been prepared by the Chairmen. ol d. .v nc w w w Hydropower & Dams Issue Two, 2008 vn Le Huu Ti, who described the ‘Green Growth’ policy of UNESCAP in his keynote address. Session 1: Hydro potential – National and regional development Christoph Mor, Mekong River Commission, Lao PDR With the initial geographic focus on the Greater Mekong Subregion (GMS), comprising Cambodia, Lao PDR, Vietnam, Thailand, Myanmar and the two neighbouring provinces in PR China, the session explored in some detail the region’s hydropower development plans. On the demand side, we roughly see two categories of countries: Vietnam, Thailand and the southern Chinese provinces show high growth rates of more than 10 per cent until 2020. Modest growth of energy demand is also apparent for Cambodia, Myanmar and Lao PDR; however, starting and remaining at very much lower levels. An impressive number of hydropower projects are currently under construction or at the planning stage. A National Hydropower Plan, a rigorous four-year exercise, supporting the prioritization of investments at country level, was recently completed in Vietnam. In Lao PDR, hydropower development is now Christoph Mor of the Mekong River Commission, who chaired Session 1 on hydro potential and development plans. Session summaries Over the two days of ASIA 2008, there were a total of twelve sessions, in three parallel tracks, covering a broad range of topics relating to water and renewable energy schemes, and focusing particularly on issues of specific relevance to the Asian region: hydro potential and development plans, rural electrification and small hydro, social and environmental aspects, project 33 The first gauging station successfully installed in a tributary of Kbal Chhay in Cambodia, described by O. Ekstrand in Session 2. w w w Prof Jia Jinsheng, of IWHR, China, and CHINCOLD. He gave an overview of China’s hydro development, and co-chaired the session on materials for dams. 34 pollution from industry (heavy metals) in water used for peri-urban irrigation around Hanoi. The keynote address presented by Dr Park of KWater described what could be termed as ‘third generation development of water resources projects’, primarily for flood control, but with emphasis on amenities. He noted that water resources development in his country had moved from large scale projects in the 1970s, through a major focus on water quality in the 1990s, to sustainable development and multipurpose use of reservoirs today – with the main functions being flood control and recreation. During the discussion it was acknowledged that the developers of schemes in the 1970s could not have envisaged how requirements would change over 30 years. ol d. accelerating rapidly, and projects now often include private sector participation, and typically feature bilateral cooperation, namely with entities from Thailand, Vietnam and PR China. Preparing the region’s countries for emerging power trade opportunities, an ADB-supported GMS initiative focuses on the policy and institutional environment, as well as on the physical infrastructure, a regional 500 kV transmission interconnection system. This was described by E.M. Baardsen of the Asian Development Bank. As Lao PDR will become an energy exporter within the next decade, the system will mainly include new interconnections from Lao PDR to Thailand, PR China and Vietnam, but also a connection between Cambodia and Vietnam. It will further cater for the rapid economic development of parts of the region with an interconnection between PR China and Vietnam. The Mekong River Commission believes that successful development of the basin’s power potential requires a basin-wide perspective, and due regard to environmental and social aspects. The preparation of a .v nc Left: Xaypaseuth Phomsoupha of the Ministry of Energy and Mines, Lao PDR, and Nguyen Duc Lien of the Mekong River Commission, who spoke in Session 1. respective programme is under way, supporting MRC member states in the development of hydropower as an asset in their economic and social development. The session then extended its geographical focus and learnt about ambitious plans to tap the substantial hydropower potential in Russia’s Far East; in particular, delegates heard of the formidable engineering challenges in the arctic environment. Another speaker gave an overview of PR China’s recent achievements in the hydropower sector, in particular in the field of large dam construction. Both speakers from outside the region confirmed their commitment to sustainable hydropower development, taking due regard of social implications and environmental impacts. vn Above: Vietnam’s planned hydro development, described by G. Lifwenborg. Session 2: Water resources and irrigation Dr Peter Lee, President, ICID Seven papers were presented in this session, three of which addressed the need for surveys and fundamental analyses, even in situations where data were limited. One stressed the great importance of local participation in the collection of hydrological data (referring to Cambodia). The second discussed the ground surveys needed in connection with the use of satellite imagery to plan the rehabilitation of irrigation systems in northern Afghanistan. The third paper in this part of the session discussed the potential impact of upstream regulation on low flows at the onset of the flood season in the Lower Mekong. Three papers dealt with various aspects of the development of water resources: one focused on the enormous potential for hydropower in Pakistan, more than 9000 MW of which is planned to be implemented by 2016. The other two papers in this group were concerned with pollution: one with phosphorous and nitrate releases from agricultural soils as a result of fluctuating inundation levels caused by the Three Gorges dam. The other concerned Session 3: Rural electrification and small hydropower Prof David Williams, CEO, British Hydropower Association Speakers from South, East and South East Asia reported on their varying experiences in rural electrification, and the role hydropower plays in plans and policy in this area. In his keynote address, Bryan Leyland of New Zealand said there could be no doubt that rural electrification was a good thing, in that it could bring large social and economic benefits. It was no accident, he pointed out, that indices of economic growth, health and social development correlated closely with the wide availability of a reliable and economic electricity supply. He described a rural distribution system suitable for use in developing countries. Three-phase distribution used to serve isolated settlements could more than halve the costs of rural electrification. Single-phase rural distribution was the norm in the USA, Australia and New Zealand, Leyland said, adding that if these countries had standardized on threephase rural distribution, the high costs would have denied power to many remote communities for many years. Hydropower & Dams Issue Two, 2008 His presentation demonstrated that, by adopting international best practice, countries of Southeast Asia could provide their rural populations with a reliable supply of electricity at a price that they could afford, without the need for large subsidies or the involvement of the major development banks. Ho Viet Hao of EVN, Vietnam, described his company’s Small Hydropower Plan, which outlines the possibility to develop a total of about 900 small schemes, with a total capacity of 6800 to 7300 MW. He stressed that small-scale hydro projects on this scale could play an important role in rural electrification. The main challenges, however, were site clearance, and a shortage of capital. L. Gibson of the Lao private company Sunlabob spoke of the operation of hybrid village grid systems, as an affordable renewable energy solution for the less developed countries. A large number of villages in Lao PDR would not be connected to the main grid for many years to come, he explained. Small village grids fed by decentralized local energy sources were therefore the best option to be explored. As flows in streams were often considerably reduced during the dry season, in many cases these resources would have to be boosted with solar generators or with a generator sets operated on biofuel. Lao Government policies supported decentralized solutions in order to reach the goal of 90 per cent electrification by 2020, he continued. Insular grids, Gibson said, had intrinsically low load-factors (sold energy compared with produced energy), because they were not able to draw on the larger grid to cover peak consumption, or feed into the larger grid during low consumption. This could make them less attractive for private investors to consider installing and operating such hybrid grids. Sunlabob has been active in the renewable energy sector in Laos for the last five years. Most systems installed by the company have in the past been solar for lighting, water pumping, cooling and communications. A successful innovation has been the development and operation of a rental scheme for solar home systems and more recently communally owned systems for schools and health posts. This effort was awarded the Development Marketplace prize by the World Bank. More recent efforts are for initiating the productive use of electricity in remote villages. A demonstration project with solar pumps for intensive horticulture is under way. In view of the Government’s policy for decentralized energy production in remote areas, and also the repeated requests by villages and district authorities, Sunlabob has looked into the possibilities of small hydro generation and the operation of village grids. The required technical knowhow is being acquired by the company through partnerships with industrial partners who provide the equipment. Another paper on renewable energy systems for remote areas described the work of the French NGO Codev Viet Phap (CVP), which had implemented, since 2000, an electrification programme for all the families of some pilot villages in North Vietnam, with financial assistance from the French Ministry of Foreign Affairs and the European Commission. Six micro hydro plants had been developed. with their own grid system, in Phu Tho and Son La provinces. Their nominal capacities, of between 3 and 15 kW, were sufficient to supply the basic electricity needs of rural families (about 200 W/family). CVP’s objective was to demonstrate, by building and operating these pilot plants, the various choices in the design, cost and construction period for such schemes, as well as how to find funding, and also to test the management approaches used for operating and maintaining the equipment in a sustainable way. The concept adopted had been based on minimizing costs by find- .v nc w w w Hydropower & Dams Issue Two, 2008 ing innovative technical solutions. Studies and construction took less than one year for each plant. Equipment was made in Vietnam and the general costs of the production plant are less than 2000 €/kW. A presentation from the Chugu Electric Power Company of Japan described the development of a submergible turbine and generator developed for the Kawahira No. 2 scheme in Japan. T. Kunshi explained that the system had many advantages for mini hydro because of its simplicity, and the fact that a powerhouse was not necessary because of the submergence of the units. As a result, sites which would not have been feasible for development with conventional equipment could be developed using these technologies. This helped to open up the market for schemes of less than 1 MW and heads of less than 10 m, he concluded. The brief discussion at the end of the session focused mainly on the cost of small hydro projects in remote and developing areas. Overall, the cost appeared justified in the context of poverty alleviation, which, it was agreed, should always take priority. The importance of optimizing the use of local resources in the building and operating of plant was stressed by all and, to achieve this, good training in technical and management spheres was paramount. More effort was required, it was agreed, in the development of appropriate equipment and sound planning for rural electrification in all developing countries, with much more collaboration on financial and technical issues between all nations. vn Bryan Leyland of New Zealand, who gave a keynote address on rural electrification. The Thanh Cong mini hydro scheme in Vietnam, one of several described by Ho Ta Khanh of France, which is being developed by the French NGO Codev Viet Phap. ol d. Prof David Williams, CEO of the British Hydropower Association, who chaired the session on rural electrification and SHP. The panel of speakers for the session on small hydro and rural electrification. 35 Frédéric Louis of EDF, France spoke of financial risks which could arise during the lifetime of a project. Dr Andy Hughes of the UK, who chaired the session on Civil Engineering challenges. Session 4: Financing Water and Energy Schemes Yongping Zhai, Principal Energy Specialist, South East Asia Infrastructure Division, Asian Development Bank In his keynote speech, Dr Pradeep Perera of the Asian Development Bank (ADB) clearly identified, from a developing financing institution’s perspective, key challenges to host governments, project developers, financiers and project-affected communities when developing hydro resources. Among the challenges facing host governments, he pointed out, it is important to sequence the project selection within the national power sector development plan, as well as river basin planning and strategic environmental studies. Project selection should not be driven by project developers, he said, therefore it was necessary to have a transparent selection process for selecting project developers. Dr Perera also highlighted issues of concern to project financiers, including ensuring the financial viability of projects, and also compliance with social and environment obligations to deal with cross-cutting issues such as biodiversity, river basin management, and rural development in the context of financing hydropower. Dr Perera prescribed some best practice approaches to address these issues. Other speakers in the session identified more specific risks for the development of hydropower projects. Frédéric Louis, of Electricité de France, speaking as a project developer, identified the main risks which could arise at any time during the lifetime of a project, including financial closure risk (loss of development cost), completion risk, operational risk and force majeure events. Peter J. Rae, of PJR Consulting Inc, USA, elaborated on another major risk, that is, power sale risk (credit worthiness of the off-taker). David Doran, of the Mekong Law Group, then highlighted typical legal risks and obstacles facing hydropower project development in the Mekong region. Once these risks are clearly and fully identified, all efforts must be made to reduce or mitigate them, and all residual risks should be properly allocated and managed. A more rational allocation of risks among each partner in the development and financing of projects should provide for a lower overall risk profile, higher returns for the investor, and improved construction performance. Rae suggested that the project owner/developer should take on a larger share of the risk than is often assumed in limited recourse financing. The owner should fund contingencies sufficient to cover the value of the risks as part of the financing package, he proposed. This means also that the project’s financial and economic feasibility should be proven for the case if the risks should materialize. However, this ownership of risk offers the potential for significant cost savings (and equity return enhancement) to the owner in the event that some of the estimated risks do not materialize. Regarding the mitigation of legal risk, Doran presented two theories in dealing with such legal obstacles: • the relevant legislative and regulatory authorities should grant exemptions only from specific laws, to allow for the performance of obligations and enjoyment of benefits guaranteed under the Concession Agreement. vn Yongping Zhai of the Asian Development Bank, who chaired Session 4 on Financing water and energy schemes. ol d. .v nc w w w Gianni Porta of Impregilo described extreme climatic conditions at the Karahnjukar site: the photo shows the winter protection and heating system for the concrete plinth. • the project documentation should supersede all conflicting local laws and should be approved by the legislative branch of the relevant country as a law; and, 36 The mitigation of social and environmental risks and associated public relations risk in developing hydropower projects were fully addressed by the speakers, particularly the project sponsors. These risks could be further elaborated at the next conference, based on best practices and lessons learnt in various parts of the world. Session 5: Civil engineering challenges Dr Andy Hughes, Atkins Global, UK Facing challenges is indeed what civil engineers do every day, the Chairman pointed out, and he added that this was what made civil engineering so exciting. The papers presented illustrated some of the challenges we face as we strive to improve conditions around the world for our populations, including the provision of water and power. In so doing, we are often are having to work in more and more remote areas of the world, in difficult climatic and geological settings. A keynote speech in the session focused on managing the challenges of a large dam site in Iceland, and eight other papers covered a number of issues. It is clear that from the papers in Session 5 that there are some common themes covering the problems we face, namely: • Extremes of weather: mainly hydrological, resulting in the need to deal with floods and flows but in two cases the extremes of the weather in terms of heat and cold and associated wind. • Geological surprises once construction starts, causing delays and cost increases, posing the old question as to whether we are spending enough time and money on site investigation. Hydropower & Dams Issue Two, 2008 said. On this aspect, one participant made the point that automatic monitoring of performance over time is essential for appropriate and timely maintenance. A paper from Alstom Hydro on the latest advances in large-size hydro units in Asia was presented by Philippe Gilson. He presented technical details of the 350 MW/67 m head Pen Shui Francis units in China, along with information on other similar sized units in India, China and Vietnam. Of particular interest were the 281 MW/86 m head Francis units at Subansiri in India which, with a runner diameter of 7 m, are the largest Francis units in the world to be designed for bottom dismantling of the runners. Gilson also gave details of Alstom’s recent large Kaplan and bulb units supplied to China; notable among these are the bulb units for Chang Zhou (47 MW/16 m head) and Qiao Gong (63.6 MW/24.3 m head), the former being the largest bulb unit supplied by Alstom and the latter the most powerful. In the next presentation, Dr Helmut Keck from Andritz VA TECH Hydro gave a detailed analysis of the advantages and disadvantages of using Pelton or Francis units in the overlapping head range, where either would be feasible. Keck successfully demonstrated that a Francis unit would be the obvious economic choice at sites where: the water is pristine, part-load running is not a major requirement, and the required submergence can be economically accommodated. Equally, the Pelton design would be the preferred choice where heavy abrasive silt loads are expected, peak efficiency is not a major consideration and part-load running is paramount. Between these two extremes the choice is far less obvious, and requires close consultation between the purchaser’s representatives and equipment manufacturers, to establish the most suitable choice. With respect to silt damage to turbines, Keck summarized his company’s experience with High Velocity Oxygen Fuelled (HVOF) coatings on Pelton and Francis tur- bines operating in China, Iceland and India. The photographs he presented demonstrated with astounding clarity the severity of the erosion problem and the obvious benefits of coatings. The theme of the ever-increasing size of hydro developments in China was continued by Lin Yanzhong of the Voith Siemens SHEC manufacturing facility in China. Yanzhong gave details of many of the large Francis units recently supplied by Voith, including the 710 MW/80.6 m head units at Three Gorges, the 714 MW/140 m head Lon Tan turbines, the 711 MW/205 m head La Xi Wa turbines and the 714 MW/216 m head turbines at Xiao Wan. Lin also gave details of a projected 1000 MW medium head unit, and spoke of the need to reduce vibrations in these large units by special model testing and hydraulic and structural frequency analysis. The subject of runner vibrations during starting was broached, as were measures taken to avoid guidevane cascade failure. Experience with HVOF coatings at the Kaligandaki A hydropower plant was the subject of a presentation by Bhola Thapa of Kathmandu University, Nepal. The Kaligandaki units are 48 MW/115 m head Francis turbines, which are subjected to heavy monsoonal silt loads. Although the upstream de-silting facility is designed to remove silt particles greater than 200 mm, the smaller diameter silt which passes through the facility still causes substantial damage to the surfaces of unprotected hydraulic channels. .v nc The issue of adequate site investigations, coupled with the correct procurement methods and the right attitudes which engender cooperation between the client, contractor and designer, require further debate in the future. The Pen Shui runner (China) after heat treatment, described by P. Gilson. w w w Session 6: Hydro machinery – design and operation Chairman: John Gummer, Hydro Consult Pty Ltd, Australia The keynote address given by the Chairman was on quality control of hydro-mechanical and electrical equipment. He explained that the popular misconception of quality control of hydro equipment being limited to manufacture and erection ignored quality concerns at the equally important stages of the feasibility study, specification, contract administration and operation and maintenance. At the feasibility stage, a correct choice of equipment and arrangement was paramount, he said, and no amount of manufacturing quality assurance could compensate for mistakes made at this stage. Equally, Gummer emphasized that a specification was not just a “collection of words”. Its purpose was to define the needs of the purchaser and the responsibilities of all parties. If any aspect were not specified, then the purchaser would have no contractual right to demand it. There is no substitute for high quality operation and maintenance both in documentation and practice, Gummer Hydropower & Dams Issue Two, 2008 vn • Close cooperation: the need for close cooperation of all parties (contractor/client/designer) at all stages of the project, but particularly during construction. • The need for training and succession planning. • The need for simplicity of design where possible. • The need for the consideration of social and environmental aspects as being essential to achieve success in a project. • The need to select carefully the appropriate plant and machinery for a project, to ensure that the scheme is completed on time and within budget. Dr H. Keck of Andritz VA TECH Hydro gave examples of erosion protection. ol d. John Gummer chaired the session on Hydraulic machinery, and gave the keynote address. Deputy Minister of Electric Power of Myanmar, who headed the delegation from his country. 37 flow in micro hydro approach channels with a view to optimizing output for any given perturbation. Kouchi explained in detail the mathematical basis for the model and presented several comparisons between the predictions of the mathematical algorithm and the results from a laboratory model. vn ol d. Thapa demonstrated favourable experience with HVOF tungsten carbide ceramic coatings, comparing inservice prototype performance of various component mixes with each other and with laboratory tests in a rotating disc rig. The importance of the combined effects of cavitation and silt erosion was shown, the detrimental effects of their combined action being far greater than those of each acting alone. In response to a query from the floor, Thapa confirmed that as a result their hardness, HVOF coatings were difficult to repair successfully. The presentation by Hirofumi Etoh from Voith Fuji, Japan, covered important technical details of the rehabilitation of the Bath County generator-motors in the USA. The stator windings had originally been supplied with 360o Roebel transpositions, but by the relatively simple measure of supplying the new windings with 540o Roebel transpositions, the circulation and stray losses had been considerably reduced with a resulting decrease in winding temperature for a given output. This, coupled with improvements in the cooling air circulation, had resulted in an uprating of the generator-motor from 447 MVA to 530 MVA. Eroh confirmed that these modifications with similar results to those obtained at Bath County could be applied to any large unit with stator cores long enough to accommodate the new transposition. The final presentation, by Yuichi Kouchi of the Chugoku Electric Power Co Inc, Japan, concerned the numerical modelling of unsteady w w w .v nc Flooding in Bangladesh, from the keynote address by Dr A. Hughes in Session 7 on Safety and risk. Session 7: Safety and risk Prof Luis Berga, President, ICOLD The first part of the session dealt with flood risk, prediction and mitigation. The increase in the world population, economic growth and intense urban development in flood-prone areas has caused a major increase in the impacts and economic damage caused by floods. Current assessments estimate that one billion people live in the potential path of floods with a 100-year return period. Two billion people could be vulnerable to floods by 2050. Key conclusions from the session papers and discussion can be summarized as follows: It is urgent to apply a holistic approach and integrated perspectives, and effective integrated flood management policies must be developed. In assessing flood mitigation options, all possible and feasible options must be considered and implemented jointly and in a coordinated way, including structural and non-structural measures. Increasing investments in structural and non-structural measures is necessary to achieve “water security”. The strategy should also incorporate the most effective non-structural measures, working with nature, and include coping with risks. Dams and dykes should be considered as one of the effective infrastructure elements in flood risk management, and they must be developed in an economically, socially, and environmentally just and sustainable way. The international development and financial institutions should focus more on disaster-risk reduction and move from response to preparedness for risks. Some of the current problems and crises involving floods can be attributed to greater climate variability. It is likely that, in the future, global warming will increase the intensity and frequency of flooding in most regions of the world, with a growing occurrence of extreme floods. Thus, new scenarios should be considered in the relationship between floods and infrastructure. In general, it will be necessary to adapt to more frequent and severe floods, and in this context dams and dykes could play an important role in flood mitigation. The panel of speakers for Session 8 on civil engineering materials for dams. 38 Some specific topics covered in the session were as follows. In a keynote paper entitled ‘Flood risk and reservoir safety in the 21st century’, Prof Andy Hughes of Atkins Global, UK, presented some statistics on the frequency of floods and the number of lives lost and damage caused by flooding. He then proposed some measures which could mitigate national disasters. He stressed the need for expertise to be passed on to young engineers, for the benefit of future generations. Van Thanh Van Nguyen, of Mc Gill University, Canada, described recent advances in statistical modelling of extreme rainfall and floods. He gave an example of the methods he had described, based on data from 200 catchment areas in Canada. A paper from the Vietnam Institute for Water Resources Research dealt with flood protection along Vietnam’s 200 km of coast, where there are many large estuaries and delta regions, and riverbeds are characterized by soft and weak ground. He pointed out that building flood barriers based on traditional technology could be difficult, and that research was necessary on new methods. A paper from Japan dealt with the rehabilitation of an old gravity dam to enhance its flood discharge capacity and seismic stability. The original Taishakugawa dam and powerplant had begun operation in 1924; a recent refurbishment scheme, described by I. Yoshioka of the Chugoku Electric Power Company of Japan, had brought the scheme in line with current safety standards. In the second part of the session, two papers looked at geology and seismic design. N. Mulyanto of PT PLN, Indonesia, gave a talk on seismic design in his country (which has widely varying seismicity). He drew attention to one case where he felt that the choice of a low seismic coefficient had led to cracking of an underground powerhouse. The last paper, presented by E. Frossard of Coyne et Bellier, France, described the challenges of tackling complex geology, and in particular the seismic design of the KoudiatAcerdoune dam in Algeria. During excavation works for this scheme, slope instabilities had been discovered, and it was clear that a major landslide was about to move about 1 ¥ 106m3 of rock on the left bank. As a result, key features of the dam’s profile had been optimized, and the foundation level had also been revised. Before concluding, Prof Berga outlined briefly the mission of ICOLD, a non-governmental international organization with 88 member countries and more than 10,000 individHydropower & Dams Issue Two, 2008 w w w Hydropower & Dams Issue Two, 2008 RCC placement at the Son La dam in Vietnam, in February 2008 (discussed in Session 8). vn 19 arch dams) and there were a further 34 dams under construction (of which 10 were arch dams). Dr Jia laid particular emphasis on these RCC arch dams, the highest being Dahuashui at 135 m high closely followed by Shapai at 132 m, which has been in operation for some six years. He also described some of the detailed investigations leading to Longtan, the highest and largest RCC dam in the world (192 m high; RCC volume, 4.65 ¥ 106m3). Longtan also has the fastest placement rates, 18 476 m3 in a day and 400 754 m3 in a month. Jia briefly touched on the development of CSG dams (cemented sand and gravel, a similar concept to hard-fill dams) and showed an example of a CSG cofferdam which had been overtopped by 8 m of water. Luong Van Dai gave an overview of the state-of-the-art of RCC dams in Vietnam. Although the first RCC dams in the country (Pleikrong, A Vuong and Dinh Binh) are just being completed, Vietnam now has 11 high (> 60 m high) RCC dams under construction, that is, half of the total number of high dams under construction in Vietnam. Five of these RCC dams are more than 100 m high, which is the third highest number of any country in the world (after China and Japan). The largest of these RCC dams is Son La (to which there was a visit after ASIA 2008) with a height of 139 m, a length of 960 m and a total volume of more than 5 ¥ 106 m3, of which 3 ¥ 106 m3 is RCC. Dai described the different pozzolans used in Vietnam: in the case of two dams flyash, but in the rest of the cases natural pozzolan. The maximum size of aggregate in Vietnamese RCC dams ranges from 40 to 60 mm, and the total cementitious content from 180 to 290 kg/m3, of which 60 to 90 kg/m3 is Portland .v nc Session 8: Civil Engineering materials for dams Co-Chairmen: Dr M.R.H. Dunstan MD&A, UK; and Dr Jia Jinsheng, IWHR and CHINCOLD, China There were seven papers presented in the RCC (roller compacted concrete) part of the Session and three on CFRDs (concrete-faced rockfill dams). There were seven papers dealing with RCC dams, two of these were summaries of the development of RCC dams, the first in China (by Dr Jia Jinsheng of IWHR) and the second in Vietnam (by Luong Van Dai of EVN). One paper dealt with a particular RCC dam, Dinh Binh in Vietnam (by M. Ho Ta Khanh) and three described trial mix programmes and full-scale trials for RCC dams. Two papers focused on Dong Nai 3 in Vietnam (by Marco Conrad and Ernest Schrader) and one described the work at Son La, the largest RCC dam in Vietnam (by David Morris of Colenco). The final paper (by Alberto Scuero of CARPI) described the installation of geomembranes at two RCC dams. The discussion in Session 8 on RCC dams was very appropriate, in view of the fact that nearly 30 per cent of all the RCC dams in the world are in Southeast Asia, and these include the great majority of the very high RCC dams. Dr Jia’s presentation on the RCC dam technology and experience in China included a description of typical RCC dams in China. Dams of this type have been under construction in China for more than 20 years, and by the end of 2006, 92 RCC dams had been completed (including The 135 m-high Dahuashui RCC arch dam in China, described by Prof Jia Jinsheng. cement, while the pozzolan content ranges from 110 to 210 kg/m3. M. Ho Ta Khanh described the design and construction of Dinh Binh dam, one of the first RCC dams in Vietnam. The design of this dam had been changed from a traditional concrete gravity structure to a partial RCC dam shortly before the start of construction. The actual volume of RCC was a relatively low percentage of the total: 170 000 m3 of a total of 430 000 m3. Being one of the country’s first RCC dams, the design had been very conservative, with a 1.5 mthick upstream wall of CVC backed with GE-RCC and the slope-layer method of placement had been used for the RCC. The last three layers had been placed together, and then the placement had been stopped for six days (for thermal reasons), so the placement was therefore very slow. The temperature in the CVC reached nearly 60o C and this had initiated cracks which had propagated into the RCC. The cracks had been grouted and sealed with a polymer resin. The cost of the RCC at Dinh Binh had been very high, representing nearly 80 per cent of the cost of the CVC (outside Vietnam the cost is usually between 40 and 60 per cent). Ho Ta Khanh gave a number of suggestions which could reduce the cost. Dr Marco Conrad gave the first paper describing the trial mix programmes and full-scale trial for the Dong Nai 3 dam in southern Vietnam. The owner has asked for the RCC at this dam to be placed within 17 months during a tropical rainy site. With a volume of about 1.15 ¥ 106 m3, this would require an average monthly placement rate of some 70 000 m3. ol d. ual members. He explained that ICOLD provides a forum for the exchange of knowledge and experience in dam engineering. He added that ICOLD was now focused on the dissemination of dam technology in particular to the developing countries, to ensure that future dams will be built and operated safely, efficiently, economically, as well in an environmentally sustainable and socially equitable way. Another important current task of the organization, he said, was to promote public awareness of the beneficial role of dams in the sustainable development and management of the world’s water resources. For that reason, Prof Berga said, ICOLD always supported the conferences organized by Hydropower & Dams; he felt the ASIA 2008 symposium had provided an excellent opportunity to gather more knowledge about developments achieved in the emerging and developing countries in recent years, especially as regards of hydropower development. The Dinh Binh RCC dam in Vietnam, described by M. Ho Ta Khanh in Session 8. 39 Dr Alberto Scuero, of CARPI, Switzerland, who described the application of geomembranes at various Asian projects. vn ent gradations, different combinations of the basalt aggregate, with different cement contents, and with and without pozzolan. In addition, a significant number of split tensile tests had been undertaken. These had related to the compressive strength, and a reasonable relationship had been derived. Similarly, extensive testing of the modulus had been undertaken and again related to the compressive strength at various secants. Conrad concluded by explaining that, from these very extensive tests, the strength requirements of the RCC could be achieved with mix proportions of between 75 and 90 kg/m3 of Portland cement with no pozzolan, using the basalt aggregate. He gave a brief description of the full-scale trial but unfortunately no in-situ tests were available at the time of the presentation. David Morris gave the Keynote Address at the beginning of the Session. In describing the Son La dam, he noted that its primary function is flood alleviation, particularly protection of the Hoa Binh dam and power station downstream, and the second function is the generation of nearly 10 000 GWh/year. He described the two-stage trial mix programme and the three fullscale trials which had taken place over a four-year period before RCC placement. The trial mix programmes had been conducted to assess the performance of the potential cementitious materials: a flyash from Pha Lai, two natural pozzolans and a milled basalt from the Son La site. The flyash from Pha Lai had a very high Loss on Ignition (LoI) ranging from about 15 to 25 per cent. To study the implication of this high LoI, flyashes had been prepared with three levels of LoI, 5, 7.5 and 20 per cent, so that a limit could be defined. During the trial mix programmes, the flyash was found to have a very reasonable performance, and surprisingly the LoI made very little difference to the strength properties. ol d. As all the completed RCC dams that have achieved this rate of placement were high-cementitious content RCC dams, this form of RCC was chosen for Dong Nai, together with a simple construction methodology. Two aggregates had been considered, a vesicular/weathered basalt and a metamorphic sandstone. Following the initial trial mixes, it had been concluded that the basalt was so variable (with specific gravity ranging from 2.37 to 2.77 and absorption from 1.5 to 11 per cent) that it was unusable in a high-cementitious RCC as it would be impossible to maintain any reasonable quality control. Therefore metamorphic sandstone had been chosen, and it had been demonstrated that all the required properties could be achieved with reasonable mixture proportions. The construction of the full-scale trial seemed to confirm these conclusions. It was concluded that the basalt aggregate could only be used in a low-cementitious RCC, but even then only if a very intensive QA/QC system were implemented. Dr Ernest Schrader delivered the second paper on the trial mix programme and full-scale trial for Dong Nai 3. He described the two aggregates of different qualities which had been available: metamorphic sandstone and basalt, which consisted of solid basalt, vesicular basalt and dirt seams. The advantage of the latter was that it had a significantly lower coefficient of thermal expansion than the sandstone. He described a very extensive series of trial mixes (undertaken after the initial series described by Dr Conrad) with differ- w w w .v nc Final stages of the installation of a geomembrane at the Taishir dam in Mongolia, as the reservoir begins impounding (described by A. Scuero in Session 8). F. Lempérière and Sultan Alam, both of France, who co-chaired Session 9 on Optimizing hydro plant design and operation. 40 A preliminary full-scale trial was conducted in mid-2005 to ‘prove’ that RCC could be produced using the materials available and to choose a suitable retarder. A second trial was undertaken in mid-2007 to train the engineers who would be working on the dam. A third trial was conducted in late 2007 to compare at full-scale RCCs with different LoIs. In spite of the results of the trial mix programme and full-scale trials, it had finally been decided, Morris said, to limit the LoI of the flyash to 6 per cent, in line with the basic requirements of ASTM C618, although this Standard allowed a limit of 12 per cent LoI if supported by laboratory tests. The RCC placement at the dam started on 11 January 2008. During the final presentation, Dr Alberto Scuero showed a considerable number of slides describing applications of geomembranes for dams. He traced the development of the use of the material as an upstream watertight membrane over several years. An example he focused on was the use of an upstream membrane for the Taishir RCC dam in Mongolia. Access to this dam was very difficult, he explained, noting that it was located more than 1000 km from the capital, Ulan Baatar. The temperature range at this site is from -50oC to +40oC, with frequent freeze/thaw cycles, making conditions very difficult. The dam had been designed with a lowcementitious RCC and an upstream membrane to provide watertightness, Scuero said. Three different systems had been used to install the membrane for: the area always underwater; the area usually underwater; and, the area at and above the top water level. The membrane had been installed in about 11 weeks. Scuero also described the use of a geomembrane for the repair of a crack underwater. The presentation concluded with a brief description of Meander dam in Australia. The upstream face of this dam had been formed using precast concrete panels and a geomembrane had been installed on the outside. The installation of the latter had taken only four weeks. Session 9: Optimizing hydro plant design and operation Co-Chairmen: F. Lempérière, Hydro Coop, France; and S. Alam, Consultant, France (1) Sediment management The keynote address, by S. Alam, was entitled ‘Run-of-river low head hydro projects: a sustainable solution for large rivers, carrying high fine sediment loads . Alam pointed out that large sediment-carrying rivers around the Hydropower & Dams Issue Two, 2008 w w w Optimizing design and operation Most hydro plants today, and even more in the future, will operate within large electric grids and will be Hydropower & Dams Issue Two, 2008 vn Division, focused on the deep significance of land loss for affected peoples’ livelihoods. She suggested that focus is on livelihood development rather than on livelihood restoration as a way to stress improvement. Building infrastructure and improving income in the short term are routine effects, while helping affected people to become beneficiaries of projects is a challenge. This challenge calls for innovative approaches, including harmonization of restoration with construction work, and deciding on whether the support focus should be on individual households or on the collective local community. Stephen Sparkes, senior social scientist at Norplan/Multiconsult AS, Norway, introduced the issue of social interventions prior to the construction phases of hydropower projects. He suggested that social aspects needed to be integrated in project planning in time for feasibility studies, so as to be included in alternative assessments, and available in time for economic modelling. Four key concerns should be kept in mind: if benefits can reach people, baseline data formation is crucial for understanding project life and hence its cost analysis, the social success stories of a project (in terms of inclusion, targets reached, health prevention, for example), and proper financing to obtain targets for the development potential of a project. Anders Hjort-af-Ornas, team leader, Social, in the National Hydropower Plan (NHP) study in Vietnam, gave an account of how stakeholder interaction took place in a project doing an inventory of Marla Huddleston of the ADB’s involuntary resettlement programme gave a keynote address in the session dealing with social aspects. ol d. associated with other hydro plants, as well as thermal, nuclear, wind or solar plants. The extent of grid development and operation will be modified over the years, so it is essential to optimize the operation of each plant, not only alone, but in accordance with the changes in power needs and various associated plans. Optimized operation, it was agreed, should encompass technical data, various power sales rates, environmental problems and flood mitigation; it is thus a complex problem, but the relevant research and studies could be very cost effective: worldwide an optimization of a few per cent on an electric market of several hundred billion US$/year means annually more than US$10 billion of savings. Some of the specific topics covered in Session 9 were: • Modified operation of Nam Ngum 1 and modified design of Nam Ngum 2 according to the construction of Nam Bak dam with favourable impact on power supply and environment (by T. Suthawaree of Thailand). • A paper from Mr. O A Bahari (Malaysia) about the yearly and monthly regulation using normalized standard deviation probability density function. • A paper from Mr. Rauschenbach (Germany) about the optimization of dam cascade operation taking into account power supply, navigation and environment. This approach did also favour flood mitigation. • A second paper from Mr. O A Bahari: Utilization of a loading methodology for the cascade of hydroplanes for minimizing the effects of jump discontinuities. .v nc world, such as the Amazon, the Ganges and the Mississippi, had similar sediment transport characteristics once they reach the planes. Sediments were composed of a large proportion (about 80 to 85 per cent) of silt and clay, fine sand (about 14 per cent) and coarse sand (about 1 per cent). River discharge hydrographs were often such that, even at low flows, silt and clay were in suspension and sands deposited during the receding flood were cohesion-free clean sand, so with the increasing flood hydrographs, sand bars were eroded as the river stage increased and carried downstream without impacting the river stage discharge from year to year. In designing low head hydro projects, such as the case of Sydney A. Murray on the Lower Mississippi river (USA) built in 1990, and the Santo Antonio on the Madeira river (Brazil) currently under construction, Alam said, the design was such that the flow conditions in the upper pool do not create deposition of silt and clay, and thus no permanent upper pool sediment deposition. Project layout and structural arrangements also play an important role in these projects, he pointed out. Such a choice of low head projects also tended to limit flooding of large forest areas, as in the case of Santo Antonio in the Amazon. In addition, it was possible to transform some of the existing large storage reservoirs full of sediment into run-of-river projects with acceptable performance. To achieve this, Alam said, it was important to carry out state-of-the-art physical hydraulic modelling to define the operating characteristics of run-of-river conditions. Sediment transport at the Bakaru reservoir in Sulawesi, Indonesia, was described by H. Susilo of PT PLN (Persero) Jasa Engineering Indonesia. This project had been completed in 1990; within six years, 5 ¥ 106 m3 of sediments had been deposited and in within nine years, the sediment volume reached 6 ¥ 106 m3, almost the total storage capacity. Since then the full impact of sediment on equipment abrasion and power generation had been very severe. Remedial measures contemplated were: reservoir flushing, dredging and watershed protection. It was recommended that the proposed reservoir flushing and dredging operations should be carried out using state-of-the-art hydraulic modelling. Session 10: Environmental and social aspects Prof Anders Hjort-af-Ornas Session 10 included six presentations. The aspects covered were: livelihood restoration in connection with hydropower projects; social interventions to be taken into account before their implementation; forms of stakeholder interaction in planning; how displaced persons are seen by outsiders; river basin development requirements; and, underwater forestry. The background to these presentations, as expressed from the Chair by Anders Hjort-af-Ornas, was the growing attention in the hydropower sector to social and environmental impacts, especially negative ones. There was, he felt, upgraded attention to mitigation and its costs, and to balancing negative effects with development objectives. The keynote speech, by Marla Huddleston, responsible for ADB’s involuntary resettlement programme in the Southeast Asia Infrastructure Village level consultations for the Nam Theun 2 scheme in Laos, described by Dr Stephen Sparkes in Session 10. 41