فهرست مطالب محمدرضا حامی کوچه باغی

In-Site water harvesting is just one of the rainwater harvesting techniques with a wide range of traditional and innovative methods. Its efficiency can be improved by applying proper management and mechanization. By following the traditional architecture of Iran and modifying the existing rainwater harvesting methods, designed an In-Site water harvesting system for planting or groundwater feeding, called the Kajaveh, as a matrix of inverted cones. In order to study the influential factors on the Kajaveh system, 13 different treatments were examined. The results indicate that there is a specific base diameter and cone height which were determined according to the climatic and geographical conditions of the region and lead to the optimal operation of the Kajaveh system in water harvesting. Considering the different initial conditions for these treatments, results indicated that the case with a wall slope of 0.3 m/m, cone base diameter of 50 cm, loam soil, rainfall intensity of 12 cm/h, and rainfall length of 10 min, to yield the best rainwater harvesting results and on the average provided 14.9% more water than the unstructured state in the target area.

The purpose of soil management is maximizing the supply of water and nutrients to the plant and minimizes the soil erosion, improve soil fertility and soil physical conditions. Using in-site water harvesting methods reduces runoff from the area and increases the water stored in the soil profile. Rainwater harvesting is not a new concept, but it requires the combination of native methods with modern knowledge. Because the used technology was inappropriate for special conditions of the region, some water harvesting projects have been unsuccessful or even led to the loss of the whole crop. The suitability of an area for rain water harvesting depends on its ability to supply the technical and basic needs of the system. This study introduces a method for rain water harvesting in the area with little slope or no slope, which can be Mechanized Construction for large-scale. On the other hand, a computer simulation has been preparation and introduced for precise and scientific designing of a water harvesting system, which there has not been much effort in this case. The results of simulation indicated the reduction of concentration ability of water by Kajaweh system with decreasing the size of structure. In addition, in relatively smaller sized structures under high intensity rainfall, reduction of water concentration ability by Kajaweh system was predicted by simulation. Such trend is also expected for long time rainfall times (especially in low rainfall intensity).

In areas where annual rainfall is less than the crop water requirement, providing water for plant is necessary to grow properly without stress. One of the methods that have least damaging to the environment is rainwater harvesting techniques. The Kajaveh system is a local rainwater harvesting system that can be used in very low-slope areas and can be used in a mechanistic manner for annual crops. In order to investigate the operation of the rainwater harvesting system, computer simulations were performed. Estimating rain infiltration on sloping surfaces is the main part of this simulation. In this research, a semi conceptual- experimental method was used to estimate the infiltration of rainfall on sloping surfaces and find a structure with suitable geometric dimensions to rainwater harvesting. The results of the simulation that was prepared using this method were compared with the experimental data and after calibrating the simulation, it was used to study structures with different wall slopes. The results indicate that there is an optimal slope in which the maximum ability of the Kajaveh system to water concentrate occurs. For the soil whit Sand-Loam type, Aggregate structure, precipitation intensity of 11.49 cm per hour, rainfall duration of 10 minutes and in the conditions of structure formation in this research, a square base structure with 50 cm length and cavity depth of 10 cm (wall slope of about 22 degrees) showed the highest efficiency in water concentrating.

Irrigation is necessary for the crop growth and determining crops water requirement is essential for supplying it. In arid and semi-arid regions, air temperature plays a fundamental role in evapotranspiration process. In this study, the temperature occurrence probabilities at the levels of 50%, 65% and 80% were applied for calculation of evapotranspiration. The Penman-Monteith FAO and Hargreaves equations were used to calculate the evapotranspiration in Tabriz area. The results showed that the Wakeby distribution function had the best adaptation with the temperature data set in the study area. Using different levels of probability for temperature in determining reference evapotranspiration in the Penman-Monteith FAO method, negligible effects were seen in the obtained results so the averaged temperature data was enough for calculations at the cases that there were no needs for precise values. It was concluded that the Penman-Monteith FAO equation was not sensitive to small changes in temperature values, on the contrary in Hargreaves model, using different levels of temperature probability had significant effects on the calculated reference evapotranspiration values. Finally, results of the both methods were compared with the exact evaporation data obtained from pan and the pan coefficient was obtained for each method and suitable pan coefficient values of 0.63 and 1.22 were determined for methods of Penman-Monteith FAO and Hargreaves models, respectively.

From the mathematical point of view, the FAO Penman-Monteith equation shows a homographic function related to the wind speed. The homographic function has horizontal and vertical asymptotes. In this issue horizontal asymptote is applicable; because the vertical asymptote occurs for negative values of wind speed but the negative sign indicates the direction of the wind speed and only the absolute values of the quantities are used. By increasing wind speed from zero, evapotranspiration will increase until it reaches to a limited asymptote value. This value is the horizontal asymptote of the fractional function of FAO Penman Monteith equation. In this research the effect of wind speed variations on the evapotranspiration amounts was analyzed, with considering the mathematical framework of the Penman-Monteith equation. Meteorological data from three weather stations, including Tabriz, Isfahan and Rasht were used in this research. Results showed that in the FAO Penman-Monteith equation, wind speed effect on evapotranspiration is nonlinear and variation in evapotranspiration amounts is more at low wind speeds than high values of wind speeds. As a general result, evapotranspiration has tended to asymptote homographic function and the rate of increasing in evapotranspiration is reduced by wind speed increasing.