Small hydro power in China: A survey

355 Conceptualizations of fractured and karstic media are provided by P. J o u a n n a and C. Louis and by A. Mangin, respectively. J.M. Hosanski et al. discuss flow and heat transfer in fractured media and propose an approach for the case where the fracture geometry is accessible and the effect of these discontinuities cannot be considered from an equivalent porous medium point of view. A stochastic approach is applied by M. Vauclin and G. Vachaud to the hydric transfer in heterogeneous and nonsaturated soils; the authors are using the similitude hypothesis and consider a random spatial variability of the scaling coefficients to propose solutions for both infiltration and drainage. M. Quintard focuses on the natural convection of heat in porous media beyond the threshold where the conductive regime becomes unstable and analyses the three-dimensional convective phenomena (steady-state or periodically transient?) that may develop. Modern applications of transfer of electric current in porous media are treated by H. Londiche and F. Lancelot after a brief overview of electrokinetic phenomena. D. Leclerc et al. consider the natural or industrial filtration of colloidal particles and of suspensions through porous media. Both P. Goblet and J.P. Delhomme discuss the importance of detailed geological characterizations of the porous medium for the estimation of mass transport and flow properties. Geostatistical tools are efficient to perform the scale changes needed in modelling; however, they cannot replace all the valuable information which can be deduced from modern formation evaluation and from the variety of testing techniques. Fields of application of the preceding developments can be found in the introductory overview of G. de Marsily. Practical considerations (inspired by experience) on numerical simulations of flow in porous media are developed by J.P. Sauty and M. Vandenbeusch. Y. Emsellem concludes with a down-to-earth review of the status of hydrogeology stressing the importance of data bases and computers. The reviewer is particularly concerned that a possible English translation of these fifteen papers be conducted by bilingual experts in close cooperation with the authors. In his opinion, such an effort is both worthwhile and still timely. CLAUDE M. SAUVEPLANE(New York, N.Y.)

Small Hydro Power in China: A Survey. Hangzhou Regional Centre (Asia Pacific) for Small Hydro Power. Intermediate Technology Publications, London, 1985, vii + 107 pp, £ stg. 5.95 (Paperback). The nontraditional forms of energy supply have a decisive role in the socioeconomic developments of rural regions especially in remote areas of developing countries as it was strongly emphasized at the U.N. Conference on New and Renewable Sources of Energy. Among the various opportunities the

356 utilization of small hydro power (SHP) is perhaps the most important and remarkable solution because: (1) the electricity provided by these plants supplies light to the village communities simulating their active thinking; (2) the utilization of the available electric power for semi-industrial activities strengthens gradually the mechanical capabilities of the population; and (3) the use of power generated by SHPs assist to reduce the consumption of firewood (which is one of the main sources of energy in remote rural regions) and to improve the management of the environment in this way. Recognizing not only this importance but also the need for training and research to assist the rapid development of SHP in the developing countries the government of China - - with the close cooperation and financial support of the United Nations Development Programme (UNDP), the Economic and Social Commission for Asia and the Pacific (ESCAP) and the United Nations Industrial Development Organisation (UNIDO) - - established a regional centre in Hangzhou. The role of the centre includes also the utilization of the experiences gained in connection with the development of SHPs in China, and the applicaton of this knowledge in other developing countries within the ESCAP region as well as outside. The summarization and dissemination of the results is the purpose of this small book. The Chinese example of the development of SHP is exciting indeed. The assessment of the history of this shows e.g. that the number of SHPs was 8975 with 252 MW total installed capacity at the end of 1960 (SHPs are hydro power plants with units of less than 6 MW and installed capacities of up to 12 MW), and increased above 88,000 with installed capacity of 6929 MW. According to a preliminary general survey the total exploitable SHP potential is about 70 GW, hence about 10% of this potential is already utilized. The rapid development of SHP in China was facilitated by the policy applied to assist the construction of new hydro plants. The book summarizes, therefore the most important principles of the current policies: (1) To create incentives for the various communal groups at different levels to develop SHP, the guiding principle should be "self-construction, self-management and selfconsumption". (2) To facilitate the implementation of "the integration of construction teams and management, and the unification of the functions relating to power generation, supply and consumption". (3) To consider carefully the relationship between SHP stations and the State grid. (4) To establish a policy "relying mainly on local developments with the limited support of the State". (5) Importance should be attached to overall planning, reasonable exploitation of the hydropotential, multipurpose utilization and river management combined with power generation. (6) Local manufacture of equipment is important in achieving selfsufficiency. (7) Procedures for the construction of SHP stations must be adhered to in order to guarantee the quality of the work. (8) More importance should be attached to research and technical training, the use of local materials and the need to become familiar with new technologies. Apart from the policy aspects analysed the technical details explained in the book provide also important information for the development of SHPs. To keep

357 pace with the rapid development of SHP, it is essential to standardize the turbines, generators, regulators, valves and other equipment because it is a precondition to produce them in series and to achieve an acceptable investment cost in this way. Table III of the book provides e.g. the details of the standardized types of Chinese turbine-generator sets of upto 3000 kW capacity. The second half of the book gives several case studies demonstrating the great influence of SHP on the development of the whole region, as well as on the reasonable and economical solution of special problems. Other examples describe the structure and the process of construction of selected plants and especially their role in the development of river cascades. Important information is given also on the management of SHPs and on their cooperation with local, regional and country-wide grids of electricity supply. Finally the book is closed by analyzing the trends of the recent and expected further development. G. KOVACS(Laxenburg)

Water and energy: demand and effects. (Studies and reports in hydrology, 42) UNESCO, Paris, 1985, vi + 129pp., FF. 60. Water and Energy reviews hydrological problems arising from the development of energy resources, including power generation, mining hydrology, geothermal energy and pumped storage systems. The text was prepared by G.H. Davis, sponsored by the U.S. National Committee on Scientific Hydrology, and included contributions from representatives of the U.S.S.R., Canada and Ghana while additional technical input was provided by New Zealand and Australia. The chapters entitled '~Principal water using processes in the energy sector" and ~'Present water use and consumption in the energy sector" comprise some 75% of the text and are to be commended as thorough yet wide-ranging and authoritative reviews of the state of the art. The long-term value of this book lies within these two chapters which are the focus of the endeavours, plus the appendices which include a valuable glossary, conversion factors and unit consumptive use values. The chapter entitled "Future energy use and related water consumption through the year 2000" will date quickly as forecasts of the future water use may well prove to be unrealistic because of the impact of changing patterns of world oil prices. The final chapters on "Effects of energy development on water quality", "New methods of water use in the energy sector" and "Planning alternatives" are interesting and relevant outlines of their subjects. It is unfortunate that the publishing of this excellent review has been so delayed, presumably within UNESCO. The latest reference quoted is 1982 and the inclusion of forecasts within the text has resulted in the forecasting chapters, which fortunately represent a minor component of the whole, being virtually obselete before the publication date in 1985. J.S.G. McCULLOCH(Wallingford)