S.N. Shetab Boushehri; S.F. Mousavi; S.B. Shetab Boushehri
Abstract
Abstract
One of the problems in design of irrigation structures is sedimentation control in the inlet to the irrigation networks. Water quality for agriculture requires that the sediments be controlled and reduced to the permissible limit at their entrance point to the turnouts and irrigation networks. ...
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Abstract
One of the problems in design of irrigation structures is sedimentation control in the inlet to the irrigation networks. Water quality for agriculture requires that the sediments be controlled and reduced to the permissible limit at their entrance point to the turnouts and irrigation networks. This is possible by constructing a sedimentation basin. The bigger the basin, the best the retardation of the sediments, but the expenses are higher too. Different mathematical models are developed for sedimentation basins. Most of these models show the relationship between efficiency and effective parameters by mathematical formulas. In this research, a computer software for design of settling basins was designed in which design parameters (length, width, depth, slope and water velocity in the basin) are determined such that the basin has the specified technical characteristics and it is built with minimum cost. In this respect, operations research and a lexicographic enumeration algorithm is used. Application of this software for evaluation of construction costs of sedimentation basins in Nekouabad diversion dam Zayandehrud irrigation networks at Isfahan) showed that efficiency of these basins is 50.6% and 46.5%. If these basins were built under optimum design, about 18% and 6% would have been saved in their construction costs, respectively.
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Keywords: Sedimentation basin, Lexicographic programming, Nekouabad dam
F. Soroush; S.F. Mousavi; Kh. Razmjou; B. Mostafazadehfard
Abstract
Abstract
There is a gradual decline in the availability of fresh water to be used for irrigation in Iran. As a consequence, the use of treated wastewater and other unconventional sources of water for landscape irrigation are on the rise in arid and semi arid areas. Irrigation with wastewater changes ...
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Abstract
There is a gradual decline in the availability of fresh water to be used for irrigation in Iran. As a consequence, the use of treated wastewater and other unconventional sources of water for landscape irrigation are on the rise in arid and semi arid areas. Irrigation with wastewater changes the soil properties. Hence, a case study was performed to assess the effects of treated wastewater irrigation on nutrient and heavy metal absorption of a turf cover (DALZJ1 variety). In this research, the advanced treated wastewater (TW) of Shahinshahr Wastewater Treatment Plant was used and the effects of different percentages of water and TW (100% water, 50% water and 50% TW, and 100% TW) on three soil textures (sandy loam, loam and clay loam) for a period of 10 months was studied. Statistical design was based on a completely randomized design with factorial arrangement, with three replications. The results indicated that using TW for irrigating turf grass increased plant uptake of N and Cd. The maximum amount of K, Ni, Co and Pb was absorbed by turf grass from soils irrigated with 50% TW. Also, the absorption of P, Fe and Zn was not affected by TW in the irrigation water. Analysis of variance showed that there was no significant difference between soil textures on plant uptake of N, P, K, Cd, Co, Ni, Fe and Zn. The comparison of means showed that there was significant difference in grass Pb content among soil textures. The interaction effects of soil texture and percent TW showed that variation of uptake with increasing TW percentage in irrigation water was not linear and soil texture had no effect on the uptake of elements by this Zoysia variety.
Key words: Wastewater, Plant uptake, soil texture, Turf grass, Zoysia grass
S. Yousofi Moghadam; S.F. Mousavi; B. Mostafazadeh fard; M.R. Yazdani; A. Hemmat
Abstract
Abstract
Puddling is the most common method of land preparation of paddy fields in lowland rice cultivation. Puddling affects the physical, chemical and biological properties of soil and these changes are effective on rice growth. The soil that is more susceptible to changes in structure is easier ...
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Abstract
Puddling is the most common method of land preparation of paddy fields in lowland rice cultivation. Puddling affects the physical, chemical and biological properties of soil and these changes are effective on rice growth. The soil that is more susceptible to changes in structure is easier to puddle. This research was aimed to investigate the effects of different puddling levels on moisture content and bulk density of three dominant soil textures of paddy fields in Guilan province. The experiment was designed as factorial with completely randomized blocks having three replications. Undisturbed soil samples were taken from 3 different soils (silty clay, clay loam and loam) with cylindrical samplers with diameter and height of 50 cm. The soil samples were puddled by a laboratory apparatus. The puddling treatments were: P0 (no puddling), P1 (low puddling), P2 (medium puddling) and P3 (high puddling). Soil moisture content and bulk density of all soil samples was measured every 24 hrs for six days. Analysis of variance showed that puddling had significant effect (p < 0.05) on soil moisture content and bulk density. The water content of the puddled layers decreased with an increase in settling time. During drying period, P0 dried faster than P1, P2 and P3. In P0 to P3 treatments of the loamy soil, the moisture content decreased about 22.6, 16.3, 14.8 and 9.6% after 144 hrs past puddling, respectively. The trend was similar for other two soils. Measurement of bulk density in 0-15 cm depth showed that P1 caused bulk density of silty clay and clay loam soils to decrease 23.8 and 22.8%, respectively; however, it caused the bulk density of loamy soil to increase 4.1%. Bulk density increased with time in all the three soils. Bulk density increased with depth and this increase was higher for lower puddling levels. It seems that higher puddling levels are more suitable for paddy fields preparation because they loose water more slowly. To determine what puddling level is appropriate for different soil textures, parameters such as water infiltration, water retention and amount of water used should be investigated.
Key words: Puddling, Paddy fields, Soil bulk density, Soil moisture content, land preparation, Rice
J. Mohammadzadeh Habili; S.F. Mousavi
Abstract
Abstract
The shape factor is one of the most important physical characteristics of a dam’s reservoir. This factor is equal to the reciprocal of the slope of a line obtained by plotting reservoir depth against reservoir capacity on a log-log paper. The shape factor is used for reservoir classification ...
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Abstract
The shape factor is one of the most important physical characteristics of a dam’s reservoir. This factor is equal to the reciprocal of the slope of a line obtained by plotting reservoir depth against reservoir capacity on a log-log paper. The shape factor is used for reservoir classification and sediment distribution. In this study, a new method is proposed for determination of the reservoir shape factor. In this method, the normalized depth-capacity curve is plotted on log-log paper and then the value of shape factor could be derived as the reciprocal of the line slope. In this study, the original depth-capacity data and reservoir sedimentation data of 4 dams in Iran (Dez, Kardeh, Latian and Shahid Abbaspour) and 4 dams in the USA (Cedar Bluff, Kirwin, Nambe Falls, and Theodore Roosevelt) were used. The results showed that reservoir shape factor of all reservoirs decreased 2 to 2.5 for the first or second sedimentation measurements. In addition, the type of reservoirs was changed to type III. Therefore, prediction of reservoir sedimentation by area reduction method should be performed with reservoir type III. The most important advantage of the proposed method is the capability of plotting and comparing the normalized depth-capacity data of several reservoirs (or several sedimentation measurements of a single reservoir) on individual log-log paper. While in the old method, the depth-capacity data of each reservoir should be plotted on a separate log-log paper.
Key words: Reservoir, Sediment distribution, Area-increment method, Area-reduction method, Depth-capacity curve
