مجله مهندسی آبیاری و آب ایران
پیاپی 6 (زمستان 1390)

Mehran plain، having about 300 km2 area، is one of the widest plains of Ilam Province. Because of extensive agriculture lands، numerous shallow and deep wells are drilled in the plain، therefore، study of the groundwater as the main water resource of the area is very important. In order to study the groundwater، at first quantitative and qualitative data of wells and piezometers was collected and by inspecting the physical condition of the aquifer، the maps of potential، depth and flow direction were prepared. Based on information layer of wells، the electrical conductivity (EC) map of the area was prepared to get information about the water quality for agriculture uses. Finally، groundwater was classified for agriculture uses based on Wilcox diagram. Then، using the diagram and also EC map and sodium adsorption ratio (SAR)، the capability of groundwater for irrigation was prepared in the geographical information system (GIS). Results showed that the quality of groundwater for agriculture uses is suitable in most parts of the plain and only a small area in the western area of the plain is unsuitable.

In this research، in order to investigate climate change occurrence in west of Iran، 46 years observed data (1961-2006) of 17 synoptic stations of the area were used and evaluated. To this regard، significant variations values of maximum، minimum and average air temperatures as well as diurnal temperature range (DTR) on both annual and seasonal time series were analyzed on two steps. First، the data period was considered as three categories including: 46، 30 and 16 years، and the normal climate duration base variation temperature was identified on the all of stations. Then، significant variations were identified based on the averages values comparison، using the Mann-Whitney and t-Test methods. Data trend was evaluated from the 16 years period which was concern to recent period and has significant variations (at 95% level) comparing the other durations. Base on trend analysis results، Values of maximum، minimum and average air temperatures showed increasing and DTR decreasing variations. The maximum and minimum differences were related to minimum and maximum air temperatures، respectively. Regional investigation of results، illustrated that the most important variations were concerned to semi arid climate (Saghaz، Shahr-kord، Kermanshah and Tabriz stations). Seasonally، winter had also the most important variations. The difference between the 16 years duration and the 30 as well as 45 years durations were 85 and 60%، respectively. During the 16 years period، maximum and minimum stations which had significant trends were observed in summer and fall، respectively.

The simulation models of solute and water flux is suitable method for prediction of salinity and moisture variation in soil profile. One of solute water movement model is LEACHM. This model simulates one-dimentional solute، water and chemical reaction and root water uptake in unsaturation zone An experiment was counducted in order to consideration of solute and moisture of root zone in pistachio orchards in north of ardakan in central of Iran (32O 27 N، 53O 54 E) and LEACHM model was assessed for pistachio orchards. The capablility of this model for 30 cm depth in growth season was successfully but increased until end of season. For 60، 90 and 120 cm depth prediction was the same. In 30 cm depth the soil salinity was increased affected by the capillary rise. The prediction of LEACHM model show that soil moisture was decreased more than observed values and after several days change of moisture decreased greatly. In all of depths the soil moisture has smooth changes and this change continues until the next irrigation. It was the common points of all depths that predictions were lower than observed values. In 90- 120 cm depth moisture front moved late thus increasing of moisture had delay. In nongrowing season، the salinity decreased in soil profile because of leaching fraction and showed that salt distribution in root zone is steady state.

Investment on soil and water conservation measures require detailed study and planning based on documented experiences and evaluation impacts and benefits of measures. Introducing success of measures needs evaluation of soil and water conservation projects by a standard and uniqe method by all experts in different regions of the country. In this research، mechanical measures of soil and water conservation in the form of rock-cemented dams were evaluated in the Nasim-abad watershed with semi-humid climate and mean annul precipitation between 500 and 700 in the northwest of Shiraz using global WOCAT (World Overview Conservation Approaches and Technologies) program. Evaluation in different aspects such as social، economic، physical and human environment before and after of applied technologies carried out. Results of this research revealed that surface runoff was increased due to over grazing and rangeland change to poor drylands. Increased surface runoff caused gully erosion on natural thalwegs. Rock-cemented dams with one meter height and a total volume of 34496 cm3 were applied to control gully erosion. Although gully headcut are retreating upslope، sediment due to gully erosion was deposited behind established dams and completely filled tham. Constructed dams were not established by watershed residents and they did not gain the knowledge of dam construction and the benefits of using them. Therefore، it can be said that the participation of land users was negligible in the phase of dams establishment. Also، the results of research indicated that benefit/cost ratio was about 0. 1 that means this sort of project was not justifiable in view point of economy. As this technology could not mitigate gully development، there is not positive effects for dams unless sediment trapping. After filling dams، sediments flow over and reach to downstream rivers and Salman-e-farsi dam. Analysis of physical، ecological and economical impacts of dams construction indicated that this technology has positive feedback in view point of sediment trapping but it is not recommendable in view point of economic، ecologic and maintenance.

Shortage potable water resource and through cause that uses unusual water is as choice considerable. Iran has border water with Caspian Sea. So، an experiment was conducted to assess the effect of salt stress، Caspian Sea، on germination، length، weigh، K+/Na+ ratio، and Ca++ in a two farm crops. Selected plants were including berseem clover and hamedanian alfalfa. Plants salinized with varying concentrations of Caspian Sea، i. e. I0 (control)، I1 (periodic control and Caspian Seawater)، and I2 (Caspian Seawater). Use salinity stress signified difference on quality alfalfa and breseem. I1 treatment caused increasing alfalfa weight relatively، overaaall Increasing salt level generally caused decreasing germination، length، weight، K+/Na+ ratio، and Ca++. The results don̉t support irrigation by Caspian Seawater.

According to importance of Water Pollution، this study investigates relation between amount of Water Pollution and macro variables of economical growth and energy consumption data for1979-2007and in Iran. for investigation of causality and long run relation، used Engel granger causality and Vector Error Correction (VECM) respectively. Results show that GDP has positive and significant longrun and double-breasted causality relation with water pollution. But energy consumption effect is not significant. Therefore is suggested that consumption is controlled for reducing pollution and policies make for reducing energy consumption and switching clean energy resources reward embarrassed resources.

Water resources are limited worldwide. Deficit irrigation is a strategy to deal with this limitation. To determine the best method for corn deficit irrigation one study was conducted. This research was conducted on Shahid Bahonar University of Kerman in the spring of 2010. A completely random experimental design with one control and 18 deficit irrigation treatments in three blocks was considered. Treatments were: mild water stress (irrigation with %75 ETP)، high water stress (irrigation with %50 ETP)، fixed every other furrow irrigation treatment (C) and three partial root zone drying (Change the wet furrows in every irrigation (D1)، Change the wet furrows in every other irrigation (D2) and change the wet furrows in every second irrigations (D3)). Every treatment was conducted in three growth stage of corn (all periods of growth (T)، vegetative growth stage (M1) and reproductive growth stage (M2)). The highest biological yield was equal to 32431 kg per hectare was belonged to CM1 treatment and the lowest was 17654 kg per hectare belonged to D3M2 treatment. Water use efficiency (km biological yield per cubic meter of water) for the S (irrigation with %100 ETP) treatments was equal to 2. 57 and for D2T treatments was equal to 6. The results showed that the partial root zone drying with two intervals irrigation (28-day) was the best choice to apply deficit irrigation for corn.