SIRMOD model is more suitable tools for evaluation of irrigation systems that must be tested and evaluated before use in practice. Sensitivity of SIRMOD to input parameters in three solution methods of Saint- Venant equation was evaluated with ±25% of input parameters variation. Sensitivity analysis results was shown, model is more sensitive to input parameters in advance phase and runoff volume than other parameters (Slope, roughness coefficient and furrow geometry). Model in infiltrated water volume is more sensitive to infiltration equation coefficient and inflow respectively, than other input parameters. SIRMOD isn't sensitive to solution methods of Saint-Venant equation. Sensitivity of model is variable with soil type. The percent of input parameters variation isn't effective in sensitivity order. Therefore, the parameters must be measured with maximum accuracy consist on inflow and soil infiltration coefficients.

SIRMOD is a simulation model used in design and management of surface irrigation system. In this model, Saint-venant equation is solved by Full Hydrodynamic (HD), Zero-Inertia (ZI) and Kinematic Wave (KW) methods. Performance of this model was evaluated in the field. This study was conducted on a clay soil located in research fields of University of Tehran. Flows of 0.8-1.2 l/s was deliverd to 200 m-long furrows with 0.75 width. Field tests for determining of advance rate, runoff, infiltration, flow geometry and inflow rate were conducted and the results were compared with SIRMOD model. The results show HD, ZI and KW models estimate advance and infiltration rates to be less than field observations. This study shows that advance rate of HD model is closer to field observations than ZI and KW models. In runoff comparison, model eoverstimated the observed data. Therefore overestimation of runoff inevitably result in lower estimation of infiltration volume.

Surface irrigation models are tools for evaluating and designing surface irrigation methods. Using it, all stages of complete irrigation can be simulated and designed, and by changing the input factors, which are in fact design factors, a high-efficiency system can be achieved. The purpose of this study is to investigate the parameters of the infiltration equation, the depth of infiltrated water in the field, and the field evaluation parameters including water use efficiency in the field, percentage of runoff losses, uniformity efficiency, and deep infiltration by SIRMOD software. In this study, first, the required data were collected from the farm located in Kaboudar Ahang plain of Tasaran village with field measurements, then the existing models in SIRMOD software were evaluated and simulated which includes hydrodynamic model, zero-inertia, and kinematic wave. The results showed that the data estimated by the model were consistent with the advanced time data observed in the field. The best simulation results for infiltrated volume were predicted with an average error of 5. 5%, and runoff volume was predicted with an average error of 0. 8%. In general, based on the results of this study, the SIRMOD software has performed a good simulation of the furrow irrigation system.

Shortage and water crisis have made it essential to improve management and consequently to increase the efficiency of irrigation systems. Since a large percentage of agricultural lands in Iran are irrigated by furrow irrigation, research on this method application is required. In this study, the simulation accuracy of WinSRFR and SIRMOD models were compared and analyzed with the data taken from the farm of Agricultural Faculty, Razi University, Kermanshah, Iran, where the field experiments were also performed. The farm soil had clay loam texture with bulk density of 1. 18 g/cm3 under furrow irrigation. The length, depth, slope, and flowrate of the open-ended furrow under continuous flow were 25 m, 65 cm, 0. 007 m/m and 4 l/s respectively. The results showed that the percentage of average prediction error of advance time in the WinSRFR model was 7 percent less than the SIRMOD model. The value of λ in simulation of WinSRFR and SIRMOD models was 0. 82 and 0. 68 respectively, which estimated the error rate of 18 and 32 percent, respectively. In estimating the average infiltrated depth, the WinSRFR and SIRMOD models estimated the average infiltrated water depth with λ = 0. 97 and λ = 1. 11, respectively, showing that the WinSRFR model has carried out the simulation of application efficiency with a three-percent error and with higher accuracy than the SIRMOD model. The results showed that WinSRFR model is more applicable and higher accuracy than the SIRMOD model.

IntroductionWater scarcity is an increasingly critical global issue, causing a rise in arid lands and highlighting the need to address wasteful water usage in agriculture. Population growth, climate change, industrialization, and human conflicts have exacerbated water shortages, particularly in arid and semi-arid regions. According to the Falcon Mark index and the United Nations, Iran is experiencing water stress and a severe water crisis, threatening food security, economic development, public health, and national security. With over 92% of water consumption attributed to the agricultural sector, efficient water usage and reducing irrigation system losses are paramount. This study focuses on improving furrow irrigation efficiency by investigating surface irrigation efficiency and providing appropriate solutions. Materials and Methods The SIRMOD model, capable of simulating hydraulic surface irrigation, was employed to obtain the cut-off to Advance Time Ratio (CR) indicator. Diagrams based on soil texture, inflow rate, farm length, and the CR indicator were generated to enhance the design and efficiency of furrow irrigation systems. To ensure the accuracy of the simulation and results, the SIRMOD model was validated, and optimal CR indicators were determined for a furrow irrigation system with four different lengths and sandy-loam textured soils. A suitable field under the row irrigation system was selected, and the soil texture was determined using double-cylinder tests. Field operations included establishing forward and backward stations and smoothing the water path to prevent water from exiting the furrow. A pipe at the end of the furrow measured the output runoff using the volumetric method, and standard siphons were chosen to maintain the input flow rate. After turning on the siphons, advance and retreat times were recorded, and instantaneous runoff was estimated during irrigation. This process was repeated for three inflow rates: 0.5, 0.8, and 1.15 l s-1, with three repetitions for each rate l s-1. Results and DiscussionThe advance times in the first, second, and third furrows were 44.22, 45, and 42.88 min, respectively, while the water recession times were 293.1, 290.73, and 292.7 min, respectively. The relatively high water speed in light-textured soils and the short water regression times indicated the light texture of the farm soil and validated the test results. For an inflow rate of 0.5 l s-1, measurements revealed that half of the water volume entered the furrow along its length, while the other half exited as runoff. Simulation results for an inflow rate of 0.5 l s-1 yielded CR values of 8.37 for a 100 m length, 6.99 for a 120 m length, 5.41 for a 150 m length, and 3.31 for a 200 m length. For an inflow rate of 0.8 l s-1, optimal CR indicators were 8.0, 7.25, 6.19, and 4.63 for lengths of 100, 120, 150, and 200 m, respectively. At an inflow rate of 1.15 l s-1, the optimal CR indicators for lengths of 100, 120, 150, and 200 m were estimated to be 7.42, 6.53, 6.11, and 5.06, respectively.  ConclusionThe study's findings highlight a significant breakthrough in optimizing water usage in agriculture, a sector heavily reliant on water resources. By meticulously experimenting with different inflow rates and furrow lengths, the highest water application efficiency was attained with a specific set of parameters. An inflow rate of 0.5 l s-1, coupled with a furrow length of 200 m, resulted in an impressive water application efficiency of 83%. This efficiency correlates with a cut-off to advance time ratio (CR) value of 3.31, indicating a well-balanced water distribution system. The implications of this discovery are far-reaching, especially in regions facing water scarcity and agricultural challenges. By implementing these optimized settings, farmers can maximize their water usage while minimizing waste. This not only ensures the efficient utilization of a precious resource but also contributes to sustainable agricultural practices. Furthermore, the consistency in results, achieved through the SIRMOD model's validation, underscores the reliability of these findings, providing a solid foundation for future irrigation system designs and improvements. The expanded text emphasizes the significance of the study's findings, highlighting the efficient water usage and its potential impact on sustainable agriculture, especially in water-scarce regions. It also underscores the reliability of the results through the model's validation, providing confidence in the optimized settings for furrow irrigation systems. The best water application efficiency in the farm, 83%, was associated with the inflow rate of 0.5 l s-1 and the length of 200 m, and the CR equaled 3.31.

According to decline in water resources availability and quality and also increases population growth, one of the most important strategic policies for food security is agricultural vertical development which can be achieved by improvement of water productivity. Deficit irrigation by employing alternate furrow irrigation is one of the methods of water management in the field that its application increases water productivity and yield per each irrigation water unit. This study was conducted to evaluate and simulate the alternate furrow irrigation for wheat using SIRMOD model. To reach these aim, some experimental data for Kerman Zenderooh agricultural and environmental research center during 2005-2007 were used. This research was based on randomized complete block statistical design with four treatments normal and alternate furrow irrigation method with two planting distances 50 and 60 cm (T50, T100, T60 and T120) in three replications. Evaluation results by model showed that efficiency of application, irrigation and distribution of water can be improved 2 times in alternate furrow method as compared to normal method. There were 4, 10, 27, 43 minutes difference between observed and computed data of water time advances in treatments T60, T120, T100 and T50, respectively. In total, observations showed that alternate furrow irrigation with a spacing of 60 cm (T120) is suitable for wheat, even in sandy loam soils. This increases the efficiency of application, irrigation and distribution.

The purpose of this research was to analyze surge irrigation system performance and optimize the design and management parameters. In this order, by creating furrows with a length of 80 m and 1. 1% slope and implementing four treatments of surge irrigation in two inflow rates of 0. 6 and 0. 8 lit/s and two cycle times of 40 and 50 minutes, different water and soil parameters were collected and SIRMOD (surface irrigation model) was calibrated and evaluated. Then, the iso-performance contour plots of irrigation system were obtained to optimize cutoff time and inflow rate under maximizing of application efficiency, distribution uniformity and requirement efficiency. The results indicated that in the experimented furrows with the texture of sandy loam, by providing requirement efficiency of 100%, in inflow rate of 1. 2 lit/s and cutoff time of 170 min, distribution uniformity and application efficiency will be 84% and 60% respectively. According to the results, by providing requirement efficiency of 100% and considering the best length of the furrow in different inflow rates, application efficiency increases up to maximum 65%. But if the requirement efficiency of 90% to be considered, at different inflow rates in certain length of furrow, there is possibility of achieving to application efficiency up to 90%.

As furrow irrigation is practiced on a large percentage of farm fields in Iran, the design and operation of this system calls for improvement. As collecting the necessary data to predict of advance and recession curves in a furrow requires field accurate measurements. These operations are costly and time consuming and the use of approved models is advantageous. The main objective of this study was evaluating the hydrodynamic, zero inertia, and kinematic wave models prediction by field observation using the SIRMOD software. Sensitivity analysis for this software was performed by employing three input parameters: discharge, Manning’s roughness coefficient and furrow slope. Field experiment performed at the Research Farm of Faculty of Water Sciences Engineering, the Shahid Chamran University of Ahvaz. Data were collected from three furrows, 60, 80 and 90 meters long, with three replications and three discharges of 1.0, 1.25 and 1.5 liters. sec-1. Four indices: 45 degree line (a), model average prediction error (Er), regression coefficient (R2) and average relative error of model (Ea) were used to evaluate the model’s predictions. The results of sensitivity analysis indicated that the SIRMOD software was sensitive to variations of input parameters. The predicted values of advance phase for all models were more than the observed values, but, generally, the amounts of (a) and R2 indicated that the hydrodynamic and zero inertia models had better performance in prediction of advance phase compared with the kinematic wave model. Moreover, the hydrodynamic and zero inertia models, as in the advance phase, predicted the regression phase better compared with the kinematic wave model.

One of the main problems is the influence of surface water irrigation and non-uniform soil moisture profile below the soil surface which reduces the efficiency In this simulation, it was to influence both the water and irrigation.For this purpose, the surface flow equations and the equation of Nantes and the water in the porous medium equation to be done Rychadz Then, using the influence of surface irrigation was SIRMOD Simulation the flow of irrigation water and Results showed the model to solve the equation hydrus Rychadz error is less The accuracy of numerical simulations based on Richards equation for solving the given number of observations and comparison with moisture in the soil profiles developed in hydrus wet volume was evaluated RMSE hydrus results compared with observational values are (RMSE 0.11) and R2=./92 in different depth Was achieved. The model also estimates hydrus appropriate volume of water to furrows adjacent furrows in the soil moisture distribution can be well simulated.

It is necessary to study the efficiency of water use as an effective factor to determine water consumption efficiency and improving it. On the other hand, measuring this parameter is time-consuming and expense. Therefore, developed models that have capability to provide accurate simulations at real is vital. In this study, hydrodynamic, Zero initial and SRFR (Balance method) models were used by border irrigation during 2014-2015 for simulating applied water efficiency in wheat cultivation. Calibration results in the first year showed that the complete hydrodynamic and zero initial models had similar performance with 12 and 13% error, respectively, which was compared with the SRFR model in the second year. The results also indicated that that the SIRMOD-HD model with an average R2 of 0.89, the Root Mean Square Error (RMSE) of 1.86% and the Normalized Root Mean Square Error (NRMSE) of 5% is suitable for simulating application efficiency conditions and has better performance than The SRFR model.