This paper describes a simple runoff analysis method by using only spreadsheet software (Excel) that allows counterpart personnel in developing countries to easily predict the amount of runoff to a dam. A case study was done for the Pasak-Jolasid dam basin which has a long and wide area and also has operation problems. A single runoff does not fill the reservoir. It is difficult to separate the runoff by each rainfall due to the long duration of runoff, and therefore period runoff (runoff for some duration) should be taken into account. It was found that the runoff duration is approximately one month. Runoff ratios should be calculated by this monthly runoff depth and the areal rainfall of the previous month. The rainy season and the dry season are clearly separated in the dam basin. There are two peaks of rainfall, one in May and the other one in August/September. Most of the rainfall percolates into dry soil at the start of the rainy season, so the runoff ratios are low. As the soil moisture increases, the runoff ratios increase and become highest in September, after which they decrease.

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The conventional trapezoidal-shaped concrete-lined ditch (trapezoidal ditch) has been used for tertiary irrigation canals (irrigation ditches) in Thailand. The Modernization of Water Management System Project in Thailand (MWMS Project) introduced the U-shaped reinforced-concrete flume manufactured on the assembly line (U-shaped flume) into Thailand for the first time as an irrigation ditch. Advantages and disadvantages of the two types of concrete ditches are compared. Thus far, only dirt ditches have been constructed in deep-water rice areas and floating rice areas; therefore, experimental construction of concrete irrigation ditches, which are submerged under water for a long period in the latter half of the rainy season, were conducted for testing of suitable type and construction method. The results indicate problem-free construction of both types of concrete ditches using normal construction methods.

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The impact of forest thinning operations on surface soil physical properties was investigated under varying forest conditions. Five forest conditions were delineated into natural broadleaved forest, Japanese cedar (Sugi) and Japanese cypress (Hinoki) plantations with and without thinning operations. Ordination analysis by principal component method of the different soil physical characteristics extracted two main components regarded as water holding factor (WHF) and water movement factor (WMF). The extracted principal component (PC) values were used as dependent variables to analyze the effects of forest species and forest operations. The results showed that both means of WHF and WMF were high in natural broadleaved forest and coniferous forest plantations with operations, and low in coniferous forests plantations without operations. Overall, the highest means of WHF were found in plantations occupied by cedar with operations comparable to natural broadleaved species. Moreover, the highest means of WMF were found in cypress plantations with operations and in broadleaved species whereas cedar and cypress plantation forests without operations showed the lowest values. These results suggest that the thinning operations indirectly contribute to improve surface soil physical properties of coniferous forest plantations.

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Self-induced vibration is possibly caused by the semi-closed pipeline combining the automatic pressure regulator with the automatic constant flow valve. Thus, a test was conducted on the site to analyze the generation of the coupled oscillation between the automatic pressure regulator and the direct-acting constant flow valve. Further, the investigation was conducted in order to show the function of the constant flow valve, obtain self-excited oscillation, and to study the control measure. Consequently, when the direct-acting constant flow valve is used near the setting flow, the working mechanism activates the valve using the pipe pressure and the large self-excited oscillation can be induced. On the other hand, when the flow is smaller than that of the setting flow of the direct-acting constant flow valve, the self-excited oscillation is not generated. Further, with regard to the measures to control self- excited oscillation, it is known that self- excited oscillation is not completely restrained by merely blunting the response sensitivity of the automatic pressure regulator.

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Rainwater harvesting is defined and a review of its types is presented. Runoff farming rainwater harvesting is classified as micro-, macro-catchment runoff farming according to the catchment area and type of flow. Rooftop rainwater harvesting is also presented as good alternatives for some of the domestic uses. Some examples of the runoff farming rainwater harvesting and the rooftop rainwater harvesting together with the technologies and techniques to be implemented are presented. The Iraqi Western Desert (IWD) is a typical semi-arid region for application of rainwater harvesting. The hydrological features of IWD reflect the need for implementing water harvesting. The main wadies of this area are Wadi Horan, Wadi AL-Ghadaf, Wadi Tubal and Wadi AL-Ubayadh. These wadies are detailed with their hydrological and geographical features. Some previous practices of rainwater harvesting in IWD and particularly the Zubaidah Burkas are introduced. According to how much water can be harvested from this area, a few rainwater harvesting techniques applicable for the IWD are proposed.

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