j. behmanesh

Land-use changes and development of irrigated agricultural lands are very important factors that affect natural resources such as the quantity and quality of water resources and the environment. Land use change is attributed to two major processes. The first process is the change in land cover, which is related to the expansion or limitation of the area of land used (such as pasture, agricultural or urban land). The second process is a change in land cover management type (for example, changes in irrigation, fertilizer use, crop type, harvesting methods or surface impermeability). Recently the Urmia lake has been accompanied by a reduction in water resources and the continuation of this process can completely cause to dry Urmia Lake. One of the approvals of the Iranian government after the formation of the National Working Group for the Lake Urmia restoration program was to prevent the development of agricultural lands in this watershed since 2014. Unfortunately, no serious and effective action has been taken in this case yet, and this process has progressed to cause conflicts in this region. Game theory is one of the most important methods used in modeling and analyzing water and environmental resources conflicts.

In the present study, using GMCR + software, the water resources conflicts arising from agricultural land development has been analyzed. In this conflict, by accurately identifying the set of decision-makers and their strategies in the conflict process (Regional Water Company, Agriculture Organization, Justice, and Profiteering Farmers), the model was executed with 4 players, 6 options, and 64 states. Players' performance was assessed once as ideal behavior (importance to the environment, sustainable development, and preference of long-term over short-term interests) and then as the use of completing a questionnaire. Then 4 states in the ideal behavior as equilibrium states and 7 states in the condition of using the questionnaire results were extracted as equilibrium states. The conflict was also examined in the coalition state of 3 government organizations (Regional Water Company, Agriculture Organization, and Justice Organization). Finally, the most probable states of equilibrium in the game results were identified.

In the discussion concerning equilibrium points, it is crucial to consider that for resolving the dispute and the proposed solution, we need to examine not only the stability of these points but also the state's priority from the perspective of stakeholders. Based on the discussions and the output results of the conflict model using the GMCR+ model, the optimal response and conflict resolution can be found in scenario 12. This scenario holds a high priority for three key players: the Agricultural Organization, the Regional Water Company, and the Justice Department. However, it doesn't share the same level of priority with the Profiteering Farmers. The reason for this divergence lies in the preference for personal gain and profit pursuit over the broader interests of the entire catchment area.

In recent years, despite the imposed restrictions, the Urmia Lake Basin has witnessed a notable increase in the cultivation of water-intensive crops. This shift has transformed arid lands into irrigated ones and altered agricultural areas into residential zones. According to the principles of the tax evasion game, when land development carries no moral or financial consequences for profit-driven farmers, and they are aware that regulatory institutions will not commit excessive resources to prevent and effectively combat the expansion of illegal farmlands, Profiteering Farmers will consistently engage in unauthorized development under any conflict scenario. In light of the revenue potential of this situation and the opportunity to enhance one's social standing, Profiteering Farmers will persist in unauthorized development regardless of the prevailing conflict circumstances. The findings underscore the critical role of the Regional Water Company and the Agricultural Organization. These entities must proactively employ their legal capacities to impede and deter the expansion of agricultural lands. Additionally, the Justice Organization assumes primary responsibility as a crime prevention factor, while its secondary role as a judicial enforcer within this conflict situation appears fitting. Therefore, all situations are stable for Profiteering Farmers. It seems that creating a platform and conditions in which Profiteering Farmers do not develop agricultural land themselves or do not develop land due to the protection of government institutions, can be very thoughtful and effective.

Climate change and low water use efficiency are the main reasons for reducing the water entering the Urmia Lake. Therefore, water use management via irrigation scheduling can be an effective strategy to restore this lake. This research was conducted to investigate the effect of climatic variables on water requirements, identify water-sensitive growth stages, and prepare irrigation scheduling guidelines for wheat, which is one of the main crops in the studied region. For this purpose, crop Evapotranspiration (ETc) and Net Irrigation Requirement (NIR) of wheat growth stages were estimated by computing the daily soil water balance of the root zone for a period of 32 years (1985-1986 to 2016-2017). Dividing wheat growth period into nine phenological stages was performed using Growing Degree Days (GDDs) and Zadoks scale. These stages included intervals of [Sowing-Emergence (StE)], [Emergence-Trifoliate (EtT)], [Trifoliate-Double ridge (TtD)], [Double ridge-Jointing (DtJ)], [Jointing-Booting (JtB)], [Booting-Heading (BtH)], [Heading-Anthesis (HtA)], [Anthesis-Maturity (AtM)] and [Maturity-Harvesting (MtHa)], whose mean ETc was estimated to be 2.30, 1.33, 1.03, 3.63, 4.69, 5.13, 6.53, 7.09 and 1.35 mm d-1, respectively. The mean ETc, Effective Precipitation (Eff. P) and NIR of wheat during its growth period were estimated to be 774, 349, and 425 mm, respectively. Results showed that wheat sensitivity to water stress is high from booting to maturity, is low from sowing to double ridge and from maturity to harvesting, and is moderate in other stages. Therefore, increasing the irrigation interval in the first three stages of growth and eliminating the end-stage irrigation are recommended for water saving.

The performance of the existence emitters in micro-irrigation systems is on the basis of pressure dissipation and the inefficiencies of these systems in the pressure and discharge uniformity regulations have been reported by researchers. In this research, in order to improve emitters' efficiency in micro-irrigation systems, a new emitter named water volume control emitters was designed and evaluated. One hundred emitters were installed in the field condition on a micro-irrigation system and the applied water volume was measured until cutoff time. The experiments in pressures of 0.5, 1, 1.5, 2 and 2.5bar with three repetitions were conducted. In each repetition, the cutoff time of the emitter located in five positions at the first, third, mid, two-thirds and end parts of the lateral pipe were measured. Finally, the obtained results were evaluated on the basis of ASAE standards. In the field experiments, the maximum value of variation coefficient was obtained 3.3% in the pressure of 0.5bar (minimum pressure). Therefore, the system performance was evaluated in the excellent category in the all applied pressures. Also, the minimum coefficients of distribution uniformity (97.6%) and emission uniformity (91%) were obtained in the minimum pressure of 0.5bar so that these values were very favorable. In all of the pressure-discharge equations, the discharge exponent values were approximately estimated 0.55. The type of flow in emitters was turbulent. The appropriate performance of the mentioned emitters in creating a favorable water distribution uniformity showed that the change of view about emitters' operational mechanism and the developing new emitters with efficient mechanism can improve the efficiency of micro irrigation systems.

Investigation of the unsteady flow has an important role in water conveyance systems. In the present study water conveyance system including the storage tank, pumping station and pipeline was studied to investigate the maximum pressure due to occurrence of transient flow conditions. The transient condition was started by cutting the power of pumps and in a short time period, the change of flow condition was investigated in the supply collector. The friction losses in transient condition were calculated using Bentley Hammer software. In this process, four methods including steady, quasi steady, unsteady and unsteady Vitkovsky states were used. The pressure was measured by using a fast and sensitive pressure gauge and the observed results were compared with the simulation results and in this process the statistical methods were used. The results showed that there was not time correspondent between the period of cycles. The least amount of error for pressure, gained by method of unsteady Vitkovsky, is equal to 7.07m water at initial times and 11.79 m water in data logging period. For the maximum pressure values, maximum difference was obtained by use of unsteady method and the minimum difference by the two methods of steady and quasi steady methods. The maximum difference for the minimum pressure value was obtained for steady and unsteady Vitkovsky methods at initial and ulterior, respectively and its minimum difference was calculated for unsteady method. Increasing wave velocity had a direct effect on the maximum pressures and an inverse impact on the minimum pressures.

Mean monthly temperature is one of the most important parameters in agroclimatic studies and hence several approaches have been proposed for its precise estimation. In this study, the genetic programming approach is used to model monthly mean temperature in selected synoptic stations namely; Mashhad, Sanandaj, Tabriz, Ghazvin and Kermanshah with cold-arid climate and Yazd, Kerman, Zahedan, Bam and Zabol with warm-arid climate. Genetic programming approach was performed in two steps.1.Training and 2.Validation. In first step, the time series with six different patterns were prepared and trained. Then, in the second step, the obtained models were validated using coefficient of determination (R2) and root mean square error (RMSE) indices. Finally, based on these statistics, selected models were proposed for selected stations. The results showed that, genetic programming is an appropriate method for modeling mean monthly temperature. The result also indicated that, model performs better in warm-arid climates. The best results were obtained in 4th pattern of cold-arid and 5th pattern of warm-arid climates. Among the studied stations, Zabol showed the most acceptable results with R2 and RMSE of 0.96 and 1.91ºC, respectively.

H‌y‌d‌r‌a‌u‌l‌i‌c j‌u‌m‌p i‌s o‌n‌e o‌f t‌h‌e m‌o‌s‌t i‌m‌p‌o‌r‌t‌a‌n‌t p‌h‌e‌n‌o‌m‌e‌n‌a i‌n r‌a‌p‌i‌d v‌a‌r‌i‌e‌d f‌l‌o‌w. C‌o‌n‌s‌i‌d‌e‌r‌i‌n‌g t‌h‌e i‌m‌p‌o‌r‌t‌a‌n‌c‌e o‌f t‌h‌i‌s p‌h‌e‌n‌o‌m‌e‌n‌o‌n i‌n h‌y‌d‌r‌a‌u‌l‌i‌c s‌c‌i‌e‌n‌c‌e, i‌n t‌h‌e p‌r‌e‌s‌e‌n‌t s‌t‌u‌d‌y, h‌y‌d‌r‌a‌u‌l‌i‌c f‌e‌a‌t‌u‌r‌e‌s o‌f t‌h‌e f‌o‌r‌m‌e‌d j‌u‌m‌p i‌n e‌x‌p‌a‌n‌s‌i‌o‌n‌s w‌i‌t‌h t‌h‌r‌e‌e s‌h‌a‌p‌e‌s o‌f S-s‌h‌a‌p‌e‌d, s‌t‌r‌a‌i‌g‌h‌t, a‌n‌d c‌u‌r‌v‌e‌d, f‌o‌r f‌i‌v‌e F‌r‌o‌u‌d‌e n‌u‌m‌b‌e‌r‌s o‌f 5.8

In most civil projects، such as irrigation and drainage networks constructions، soil stabilization has an important role. Achieving maximum durability against wet-dry cycles is one of the soil stabilization objects. Therefore، depend upon project type and its importance; various hydraulic binders with different amounts are tested to obtain desirable results from technical and economical view. In this research، the effect of dry-wet cycles on engineering properties of clayey soils (low plasticity) was studied and lime، cement and lime-cement binders، with (2-6) percent of soil weight، were used. The results showed that with changing type and percent of binders، various sample durability against dry-wet cycles is different so that without binder samples did not have durability and the samples stabilized by 4% cement and 4% lime tolerance 12 wet-dry cycles. The results also showed that after dry-wet cycles، the mass and volume of sample were changed and its unconfined compressive strength was decreased so that the decrease of the unconfined compressive strength was between 40% and 60%. The present study showed that dry-wet cycles significantly cause to change the soil geotechnical properties.

Potential evapotranspiration is one of the most important and effective factors for optimizing agricultural water consumption and water resources management. One of methods for prediction of evapotranspiration is to use the time series models. In this research، application of different time series models، such as AR and ARMA، in order to predicting monthly potential evapotranspiration in Urmia synoptic station were evaluated. In this process، monthly potential evapotranspiration since 1971 to 2010 was determined and the first 35 years and last 5 years were used for model calibration and validation respectively. After selecting the best model، the potential evapotranspiration were predicted for the next 5 years. The results showed that AR (11) time series model had the best results in comparing the other models and the trend of AR (11) time series model had least error. The values of R2 and RMSE in AR (11) model were 0. 96 and 1. 85 mm/month، respectively.