مجله مدیریت آب و آبیاری
سال ششم شماره 2 (پاییز و زمستان 1395)

The impact of land use change in the water quality changes is major challenges in water supply for different expenditure. This article evaluates the land use change effects on Zayandehrood river water quality. In this study, the change of land use in two periods in 1997 and 2015 was performed by TM and ETM Landsat satellite. Then, change of water quality in the 18-year period was studied. The results showed a major decline in water quality in the river's profile with increased phosphate, nitrate, EC, BOD, COD and TDS in the study period. Pearson correlation test showed a significant correlation between agricultural land with nitrates, phosphates and electrical conductivity and between the city and electrical conductivity. Mann-Kendall test showed that the trend of the most variables is ascending. Results showed a decline in water quality as a result of land use changes on river basin to reduce rangeland, forest, water and increasing the bare lands, agricultural lands and cities. Thus, there is need to proper implementation of programs to control land use change in order to maintain ecological balance.

In order to evaluate the effects of rice transplanting cultivation on furrow and different deficit irrigation management on yield and yield components of rice (Shiroodi Cultivar), an experiment was conducted at Rice Research Institute (Mazandaran, Amol) in 2013. The research had done as randomized complete block design involving five irrigation treatments with three replications. Treatments were irrigation managements including T1 (permanent irrigation throughout the growth period), T2 (irrigation a day after the disappearance of surface water) T3 (irrigation three days after the disappearance of surface water), T4 (irrigation four days after the disappearance of surface water), T5 (permanently saturated soil throughout the growing period). Results of ANOVA indicated that different irrigation managements had significant difference (P

The scarcity of water resources indicates optimum use of the water in the agricultural field. For optimizing water consumption of cotton, a field experiment conducted in Hadji Abad, located in the Hormozgan province. The experiments were conducted in a split plot design based on the Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of the crop water requirements (i.e. irrigation based on 100, 80 and 60 percent of crop water requirement) in main plot and with the two irrigation systems (surface and subsurface drip irrigation). The results showed in both systems, 60 and 80 percent caused parsimony of water usage, respectively equal to 3,200 and 1,500 m3 ha-1, in comparison with full irrigation. Water use efficiency in 80 percent treatment, increased 0.7 percent, in 60 percent treatment, decreased 3.8 percent in comparison with full irrigation. In plants treated with 60 and 80 percent of the irrigation water requirements, yield, respectively 37.2 and 15.6 percent, the number of bolls, 37 and 9.5 percent and boll weight 24.5 and 3 percent decrease. The yield, water use efficiency, number of bolls per plant and bolls weight in subsurface drip irrigation increased 12.1, 12.7, 27.2 and 17.5 percent, respectively, comparison to surface drip irrigation. Therefore, for cotton cultivation in Hadji Abad area, application of the subsurface drip irrigation system with 80 percent of water requirement pattern is the best way to increase the water use efficiency for the drought years.

The control and managing water crisis can be offered and applied different strategies. In this regard, policies of changes in cropping pattern and deficit irrigation management can be considered as two strategies for optimal consumption of agricultural water. The objectives of this study were to evaluate the effect of these policies on the sustainability of agricultural and water resources in Aras basin. For this purpose, developing a system dynamics model of water resources management in Aras basin by considering economic and environmental aspects and three scenarios of changes in cropping pattern and six scenarios of deficit irrigation management were analyzed. Results showed that if using other strategies is not possible, combining of 40 percent deficit irrigation scenario with existing or optimal cropping pattern can be used to control and manage water resources in Aras basin. Also, reducing 3 percent of withdrawing of groundwater resources in agriculture, considering the high potential of surface water resources in Aras basin, will lead to sustainability of water resources and it was suggested that this strategy should be considered by managers as effective policy for reducing problems of water crisis in this basin.

Evaluation of water quality for water resources management is absolutely necessary.Non-point pollution are important in determining eutrophication of fresh water. The principle causes of this issue is high concentrations of nutrients in the water resources especially nitrogen and phosphorus. Understand the relationship land use and affecting factors in phosphate transport are the priority to assess the phosphate and predict its effect on surface water quality. Therefore, in this study the Soil and Water Assessment Tool (SWAT) was used for the simulation of phosphate in the Tajan watershed. Forest, agricultural and pasture, respectively contribute 54, 19 and 24 percent of the area and 24, 24 and 44 percent of phosphate. Among the agricultural cultivations, wheat fields produce the lowest load. Following the results in all land uses except pasture the main mechanism of phosphate transport has been from the sediment. The results of this study could be useful guide in order to preserve and protect the ecosystem of Tajan watershed from more degradation and promote sustainable development in this region.

In this study reduction in water consumption was evaluated in green space using hydrophobic layer and subsurface irrigation system for ornamental plants Gazanya in Shahrekord University. The experiment was done in a completely randomized design with four treatments and three replications. The treatments included surface irrigation (SI), subsurface irrigation (SSI), subsurface irrigation including hydrophobic layer with thickness of 5 mm (SSILH5) and subsurface irrigation including hydrophobic layer with thickness of 10 mm (SSILH10). During the growing season, factors such as amount of water consumption, leaf length, number of flowers, plant width, flower, peduncle and leaf area were measured. Analysis of variance results due to water consumption showed a significant difference between the treatments in a level of 1%. Maximum and minimum volumes of water consumption were respectively related to surface irrigation treatment (SI) with 656.8 mm and the surface hydrophobic layer one with the thickness of 10 mm (SSILH10) in which the value was 359.3 m. Water consumption reductions in SSI, SSILH5 and SSILH10 treatments comparing to SI were 17.4%, 32.7% and 45.3%, respectively. Analysis of variance results related to plant parameters showed a significant difference between the treatments. The hydrophobic layer treatment with 5 mm thickness had the highest yield.

Considering the effect of irrigating with Salman Farsi agro-industry sugar cane drain water farms on physical and hydraulic properties of soil, this study was conducted with a random scheme framework at irrigation and drainage research in farm of Shahid Chamran University of Ahvaz. Irrigation treatments were included mixing of Salman Farsi agro-industry sugar cane drain water farms and Karun River water: (1) mixing 75% Karun River water % sugar cane drain water farm, (2) mixing 50% Karun River water 50% sugar cane drain water farm, (3) mixing 25% Karun River water 75% sugar cane drain water farm, and (4) control treatment (100% Karun River water). The irrigation treatments resulting from mixing Salman Farsi agro-industry sugar cane drain water farms and Karun River water in three repetitions and control treatment (100% Karun River water) was selected in one repetition. Physical and hydraulic properties of soil including bulk density, total porosity, field capacity moisture and permanent wilting point moisture, saturated hydraulic conductivity and ultimate infiltration rate were measured in three depths (0-30, 30-60, and 60-90 cm) and during four months. Results demonstrated that increasing the salinity of irrigation water significantly increased bulk density, field capacity moisture, and permanent wilting point moisture, about 7.82%, 25.26% and 23.41% respectively (P

Rivers in addition to their environmental importance play a critical role in their neighboring people's lives. Karun River recognized as the most watery and longest river of Iran, in recent years, to declining flows and increasing the loading pollution sources to the river, its salinity has been increased. In this study, temporal and spatial changes in water salinity in the range of 105 km of Karun River from Mollasani to Farsiat were simulated using MIKE11 models. After calibration and validation of hydrodynamic and advection-dispersion model, numerical simulation results showed that in the effect of the loading of pollutants sources, salinity longitudinal profileespecially at the reaches of 60 and 90 km respectively positioned Ahvaz city and farmlands has increased as stepped. Maximum and minimum salinity changes take respectively place at the months of Aug. and Mar. To describe the rate of salinity variation in wetting and drying seasons, a fourth-order equation respectively with coefficient of determination of 0.99 and 0.98 was proposed. Results revealed that increasing flood discharge would lead to a significant decrease in the salinity of the river. In the month of Aug., removal of agricultural sources and in Mar., the removal of industrial and urban sources, have greatly influenced river salinity reduction at the upstream and downstream of Ahvaz, respectively. Results of this study can be used to study the effect of flow variation and pollution sources loading on the Karun River salinity and appropriate management solution provision.

Long-term forecasting of hydroclimatic variables such as maximum monthly precipitation (MMP) is very important in water resources management. The previous researches have shown that discovering association between the oceanic-atmospheric climate phenomena such as Sea Surface Temperature (SST) and hydroclimatic variables such as precipitation could provide important predictive information. In this paper, the application of two data mining techniques is offered to discover affiliation between MMP values of Urmia and Tabriz synoptic stations and SSTs of the Black, Mediterranean and Red Seas. Two major steps of the modeling in this study are the classification of SST data and selecting the most effective groups and extracting hidden predictive information involved in the data. Decision tree algorithms were used for classification and selecting the most effective groups and association rules were employed to extract the hidden predictive information from the large observed data. The results show a relative correlation between the Black, Mediterranean and Red Sea SSTs and MMP of Urmia and Tabriz synoptic stations so that the confidence between the MMP values and the SST of seas is higher than 60% forstations.