The technique for measuring the over-all value of the coefficient of consolidation both in the horizontal and vertical direction has attracted a great deal of attention. Accordingly, two-dimensional consolidation tests and a numerical calculation method of the test results have been developed to determine the horizontal and vertical coefficients of consolidation, Ch and Cv, respectively, of transversely isotropic specimens. For determining the condition of two directions of drainage, an oedometer ring with longitudinal slits cut on the ring's wall, 0.15-0.20cm wide and 10.0cm high, is used. The vertical coefficient of consolidation, Cv is determined from the one-dimensional conventional consolidation testing procedure which is based on the JIS standard.
The results of tests and calculations show that the values of Ch are about 30 times greater than those of Cv on average, ranging from 15 to 50 times as great.
The horizontal and vertical coefficients of permeability obtained from these values are also described.

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The water balance model has been modified and used in this study for the estimation of effective rainfall for lowland paddy. The component of interception was included in the water balance model. The relationship of interception to rainfall at three growth stages was established with the help of field experiments and utilized in the simulation. Eight rainfall stations in Thailand, whose rainfall records for the past 30 years are available, were selected for analysis. Simulation was run with computed crop water requirement and various values of percolation rate, ponding depth and irrigation interval to study their effects on effective rainfall, irrigation requirements and types of irrigation practiced. It was found that 150mm ponding depth and 5/6 days irrigation interval is most suitable and economical for lowland rice from the effective rainfall and efficient irrigation point of view. An attempt has also been made to reflect the effects of major variables on certain farming conditions. The two programs developed for simulation and rainfall analysis were in FORTRAN 77 and were run in IBM 3083 at the Regional Computer Center, Asian Institute of Technology, Bangkok.

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Concrete work is one of the main components for constructing irrigation and drainage projects. Not only so-called “industrialized countries” but also developing countries provide the ingredients needed to prepare the concrete.
Many projects have been implemented by use of local ingredients, with the guidance of expatriate engineers. However, the quality of concrete is lower than anticipated, resulting in shortening the useful life of hydraulic structures. This paper presents a case study of concrete prepared with local ingredients, in the work of cooperation in constructing an irrigation and drainage project in a semi-arid region. The study started by examining the conventional methods set forth in the specifications, followed by a field investigation at the project site. During this process, the following countermeasures were studied:
(1) Understanding the climatic and labor conditions.
(2) Comprehending the characteristics of each ingredient.
(3) Clarification of chemical and physical properties of cement.
(4) Installation of a treatment system for aggregates.
(5) Adoption of the weighing method for determining the mix proportion.
(6) Installation of testing equipment for quality control.
Based on these systematic procedures, the project provided the concrete for constructing both a few big structures and many small structures. Finally, it was concluded that:
(1) The concrete prepared with ingredients locally available had sufficient strength.
(2) Local cements showed slower and lower development of strength compared with those of Japan.
(3) An empirical formula developed in Japan was applicable to estimation of the mix proportion.
(4) Mixing amounts of admixture ingredients need to be modified based on experiments.
(5) Compressive strengths of concrete fluctuated considerably, so that normal distribution could not be applied.
(6) The greater part of data about slump values indicated smaller values (=7.5cm) than the target (=10cm).
(7) Sustainable quality control is needed to examine the compressive strength of concrete at 28 days of age, because of deficiencies of the conventional formula in evaluating the ratio of σ28/σ7.
(8) Wastage volume of concrete was estimated at 11%, nearly equal to the loss obtained through installation of small structures.

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By the year 2000 the global population will be 6.3 billion, with 90% concentrated in developing countries. The FAO has proposed that an overall production increase of 40% in food is needed over and above the 1985 level. Strategy for future crop production increases-65% yield increase, 15% cropping intensity, 20% area expansion-indicates ways in which additional pressure will be put on the existing arable land and environment. The projection implies further intensification of agricultural practices.
The nature and severity of environmental problems varies widely among and within developing countries, but in broad terms, Asia suffers from increased irrigation and deforestation; Near East/North and West Africa, from shortage of arable land and increasing desertification; Southern Africa, from livestock and crop pressure on marginal lands and fragile soils; and Latin America, from deforestation and increased monoculture.
In addition to serious deforestation, other problems are acute population pressure on the land, over-exploitation, and slow adaptation of traditional farming systems into sustainable into sustainable intensive production systems.
Two potential problems also exist in the livestock sector. The livestock population projections for some countries exceed the sustainable carrying capacity of the rangeland; the dominant impact is likely to be desertification and soil erosion.
Conservation and treatment of land and water degradation are not cheap. The task is to persuade policymakers of the benefits of allocating resources to an area in which benefits will only be seen in the long term. Environmental protection can be profitable even in terms of strict economic calculations. On the other hand, the costs of neglecting conservation are high in terms of human suffering and lost agricultural production.

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