Irrigation
H. Shokati; Z. Sojoodi; M. Mashal
Abstract
Introduction Arid and semi-arid climates prevail in Iran. The precipitation is also sparsely distributed in most areas of the country. Therefore, there is a need for management measures to overcome the water crisis. One of these measures is designing rainwater harvesting systems that can meet some ...
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Introduction Arid and semi-arid climates prevail in Iran. The precipitation is also sparsely distributed in most areas of the country. Therefore, there is a need for management measures to overcome the water crisis. One of these measures is designing rainwater harvesting systems that can meet some of the non-potable needs and reduce runoff in urban areas. The main components of rainwater harvesting systems in residential regions include the catchment area, storage tank, and water transfer system from the catchment area to the tank. The storage tank is the biggest investment in a rainwater harvesting system, as most buildings are not equipped with a storage system. Therefore, tank capacity should be determined optimally to minimize project implementation costs. The stored water volume and the project profit increases with increasing the tank volume. However, in this case, the price of the tank increases. Therefore, the tank capacity should be optimally designed to justify economic exploitation.Materials and Methods In order to evaluate the feasibility of using rainwater harvesting systems, the tanks’ volume was optimized. Due to the higher rainfall of Ardabil relative to the average rainfall of the country, it is expected that this area has a good potential for the implementation of rainwater harvesting systems. Therefore, this region was selected as the study area under the scenario of a residential house with 100 and 200 m2 catchment areas and four inhabitants. The amount of rainfall in the region is one of the primary parameters in determining the volume of rainwater collection tanks. Some of the precipitated water is always inaccessible due to evaporation from the surface. Nonetheless, since there is almost no sunlight during and immediately after rainfall, and also the received water enters the reservoirs shortly after precipitation, evaporation was assumed to be zero. Daily precipitation data for 42 years (from 1977 to 2019) were retrieved from the Ardabil Meteorological site. The daily water balance modeling method was used to analyze the rainwater harvesting systems due to the simplicity of interpretation, high accuracy and better general acceptance. Daily precipitation data were entered into this model and used as the primary source to meet the domestic demands. Simulation of rainwater harvesting systems was performed using daily precipitation data in MATLAB software, and the reliability of these systems was calculated for different tank volumes. Then, considering the price of drinking water and the current price of tanks in the market, the optimal volume of tanks was calculated using the Genetic Algorithm. Finally, the annual volume of water supply and the amount of water savings in case of using the optimal volumes of tanks were also estimated.Results and Discussion The results showed that the percentage of reliability is directly related to the volume of the tank, thus, the reliability percentage also increases with increasing the tank capacity. As the volume of the tank increases, the slope of the increasing reliability percentage decreases continuously, to the point that this slope becomes almost zero. Comparing the reliability percentage obtained for 100 and 200 m2 rooftops indicated that 200 m2 rooftop had a higher reliability percentage than 100 m2 rooftop due to receiving much more rainfall and meeting the water need for a longer duration. By comparing the results of overflow ratio for 100 and 200 m2 rooftops, it can also be concluded that using a fixed size tank, the overflow in 200 m2 rooftop is higher, which is due to receiving more water volume than 100 m2 rooftop. The results also showed that by using a 5 m3 tank, 44.5 and 24 m3 of water can be stored annually from the 200 and 100 m2 catchment areas, respectively, these are equal to 28 and 19 m3, respectively, if 1 m3 tank is used. The optimal tank volumes for 100 and 200 m3 rooftops are equal to 0.59 and 1.66 m3, respectively. Since the tanks are made in specific volumes, the obtained volumes were rounded to the closest volumes available in the market. Thus, a 1.5 m3 tank was used for a 200 m2 rooftop and a 0.5 m3 tank was applied for a 100 m2 rooftop.ConclusionApplication of a tank of 0.5 m3 for the rooftop of 100 m2 was the most profitable for saving 17% of water consumption, annually. Moreover, the optimal tank volume for the 200 m2 rooftop was selected to be 1.5 m3, saving about 32 % of water consumption per year. Water-saving percentages indicate the high potential of our study area for the implementation of rainwater harvesting systems.
Irrigation
Z. Sojoodi; H. Shokati; Y. Sojoodi; M. Mashal
Abstract
IntroductionThe constructive effects of green spaces on the quality and livability of the urban environment have been reported in many studies. Therefore, using methods that can accurately estimate the evaporation of transpiration in green space can help to reduce water loss. The purpose of estimating ...
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IntroductionThe constructive effects of green spaces on the quality and livability of the urban environment have been reported in many studies. Therefore, using methods that can accurately estimate the evaporation of transpiration in green space can help to reduce water loss. The purpose of estimating water demand for urban green space is also different from the purpose of determining water demand for an agricultural farm. In urban green space, the goal is to maintain good growth, appearance and acceptable plant health, while biomass production is the main goal on agricultural farms. Therefore, urban green space can typically be managed using an irrigation area that is less than the amount of water needed to produce agricultural products. Due to the limited water resources in arid areas, the use of less irrigation in urban green space can be desirable to save water consumption.Materials and MethodsThe Wucols method for estimating Water requirements in green space was developed by Castello et al. (4). They developed the Wucols water taxonomy guidelines for planting green space in California. The Wucols method estimates evapotranspiration in green space using reference evapotranspiration and a set of coefficients (Species factor, density factor and microclimate factor). PF method is the minimum acceptable irrigation for green space plants that emphasizes maintaining the beauty of the plant. In this method, the water required by green space plants is considered as a percentage of ET0 so as not to reduce their appearance and performance. In this approach, PF is a regulatory factor that is actually considered instead of Kc and multiplied by ET0, except that the emphasis is on the appearance of the plant and not on its optimal growth and yield. The IPOS method has been developed by the Government of South Australia for planning and managing water needs in public open spaces, especially sports lawns and amusement parks. In this method, the water requirement of grass in urban open space is calculated. In this method, plant transpiration evaporation (ETL) is calculated by multiplying reference transpiration evaporation factors (ET0) by grass vegetation coefficient (Kc) by plant stress factor (Kst).Results and DiscussionThe results showed that the highest rate of evapotranspiration obtained by Wucols method was 83.38 mm during 21 Jun-21 Jul. Also, the rate of transpiration evaporation during one year of the experimental period was estimated to be 556.5 mm. The results of estimation of transpiration evaporation by PF method also show the maximum amount of transpiration evaporation during 21 Jun-21 Jul and is 75.55 mm. The evapotranspiration rate during one year was estimated to be 505.9 mm. For the Ipos method, the highest rate of transpiration evaporation was estimated to be 36.38 mm during 21 Jun-21 Jul and 242.9 mm during the experimental period. Gross irrigation requirement is estimated by considering 70% irrigation efficiency for each month using all three methods. For the Wucols method, the gross irrigation need during one year was estimated to be 794.8 mm. For the PF method was 722.7 mm and for the IPOS method was 346.9 mm. According to the reported irrigation records for the study area, which is 900 mm per year, the Wucols method has the closest result to the irrigation records.ConclusionThe results showed that the Wucols method has the best and closest estimate according to the irrigation records of the study area. The gross irrigation requirement calculated by the Wucols method during a year is 794.8 mm, which is 12% less than the gross annual irrigation requirement of the studied green space. While PF and IPOS methods determined the amount of gross demand 20 and 62% less than the annual irrigation rate in the region, respectively. The results of this study show that the Wucols method for estimating the water requirement of plants in urban green space where there is a combination of different plant species is more reliable than the PF and IPOS methods due to the diversity of species, vegetation density and different climates.
ali javadi; M. Mashal; M.H. Ebrahimian
Abstract
Infiltration is a complex process that changed by initial moisture and water head on the soil surface. The main objective of this study was to estimate the coefficients of infiltration equations, Kostiakov-Lewis, Philip and Horton, and evaluate the sensitivity of these equations and their coefficients ...
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Infiltration is a complex process that changed by initial moisture and water head on the soil surface. The main objective of this study was to estimate the coefficients of infiltration equations, Kostiakov-Lewis, Philip and Horton, and evaluate the sensitivity of these equations and their coefficients under various initial conditions (initial moisture soil) and boundary (water head on soil surface). Therefore, one-and two-dimensional infiltration for basin (or border) irrigation were simulated by changing the initial soil moisture and water head on soil surface from irrigation to other irrigation using the solution of the Richards’ equation (HYDRUS model). To determine the coefficients of infiltration equations, outputs of the HYDRUS model (cumulative infiltration over time) were fitted using the Excel Solver. Comparison of infiltration sensitivity equations and their coefficients in one-and two-dimensional infiltration showed infiltration equations and their sensitivity coefficients were similar function but quantitatively in most cases sensitive two-dimensional equations and their coefficients were greater than one dimension. In both dimensions the soil adsorption coefficient Philip equation as the sensitive coefficient and Horton equation as the sensitive equation under various initial moisture soil and water head on soil surface were identified.
T. Asadollahzadeh; M. Mashal; S. Karimzadgan
Abstract
Saturated hydraulic conductivity (Kfs) and sorptive number are the most important hydraulic characteristics effective on soil process. Cased boreholes falling-head permeameter (Philip method) is the one of hydraulic conductivity measurement borehole method. The analysis borehole cased falling-head in ...
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Saturated hydraulic conductivity (Kfs) and sorptive number are the most important hydraulic characteristics effective on soil process. Cased boreholes falling-head permeameter (Philip method) is the one of hydraulic conductivity measurement borehole method. The analysis borehole cased falling-head in unsaturated area promoted and investigated .This method has been investigated by HYDRUS- 2D simulator but in this study is not use experimental data. The purpose of this study precision investigation and determine Reynolds method accuracy by experimental data. Thirty boreholes has been prepared, 12 boreholes with 4 different length and 4 centimeters diameter, 9 boreholes with 3 different length and diameters of 6 and 8 centimeters (3 replications done for each length). A program was written by FORTRAN language for solving the equations presented by Reynolds. Shaghaghi et al determine soil hydraulic conductivity by Guelph method in mentioned area. The results gained by FORTRAN program compared by Shaghaghi et al results. Results showed that the best data drawdown zone for determining Kfs and α* is lower range of data. Considering studies is shown that diameter and length of cased boreholes are not effective on investigation and every length and diameter can be used for solving Reynolds equation. Also the results show that the best gravity factor for precision of estimation is obtained in zero value.
N. Nikamal Larijani; A. Hassanoghli; M. Mashal; A.M. Liaghat
Abstract
Abstract
By increasing the world population and more need to supply food, farmers attend to use of chemical fertilizers, organic manures and pesticides. Also, applications of these agents without attention to their side effects, cause more problems to human health and environment. Nitrate is one of ...
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Abstract
By increasing the world population and more need to supply food, farmers attend to use of chemical fertilizers, organic manures and pesticides. Also, applications of these agents without attention to their side effects, cause more problems to human health and environment. Nitrate is one of the most important elements of organic manures, which leach through soil to surface and ground waters by irrigation or precipitation. So, it’s necessary to monitor the behavior of it. The purpose of this study was to determine the nitrate transport through two different soil textures, loam and silt loam via application of organic fertilizers. In this study, experiments were carried out by cylindrical drained plastic lysimeters with 100 cm height and 60 cm diameter, filled by uncondensed soil up to 60 cm height. Three different organic manures (poultry, cow and sewage sludge) were used on top soil of lysimeters by the rate of 35 tone/ha (upon the average use amounts of farmer's). 24 lysimeters were prepared; 9 lysimeters for 3 types of manure with 3 replicates and 3 without manure used as control for each soil type. The results were analyzed by a factorial experiment in a completely randomized form statistical design. Irrigation was done by one week intervals, totally three times with well water. Five drainage water samples (100 ml each sample) were taken through the first pore volume drained after irrigating of lysimeters. It means that each pore volume divided to 5 equal parts for sampling. The results showed that the nitrate concentration in loam soil was more than silt loam soil in drainage water samples, so it can be attributed to the effect of soil texture. Also for both soil textures, sewage sludge treatment was caused the most nitrate concentration, and the least was monitored in control treatment. The amounts of poultry and cow NO3 in drainage water samples were between them, respectively. Considering the one week irrigation intervals and three consecutive irrigations which were done, the amount of contamination in both soils in the first week was highest and in the third week was the lowest; it can be related to nitrate leaching by irrigations done.
Keywords: Water pollution, Nitrate leaching, Lysimeter, Organic manure
