Iranian Journal of Irrigation and Drainage
Year:2021 | Volume:15 | Issue:3|Papers Count:20

The electrical conductivity parameters are directly related to the water salinity, and its variation trend indicates the variation trend in water resources salinity. Regarding Iran's water resources, there is a concern that due to climate change and drought in recent years, as well as increased water consumption compared to the past, the quality of these resources in terms of salinity is growing. In this study, the Mankendall trend analysis test by eliminating the discharge background effect (noise), which is a documented method in trend analysis on time series without a specific statistical distribution. In order to find the variation time-trend, the electrical conductivity (EC) parameter was used in 20 hydrometric stations located on different rivers of Iran. In selecting hydrometric stations, climatic, hydrological, land use index and different geographical conditions have been considered as effective factors. The results of this test provide a clearer and more citationable perspective of the salinity process. These results indicate the increasing trend of salinity in Moshiran (Darreh River), Samian (Qarasu River), Ahvaz (Karun River), Doab Nosard (Sirvan River), Maraveh Tappeh (Atrak River) and Nozarabad (Nekaroud River) stations and (30% of selected stations). Among control strategies and reduce this trend are observance of rivers and wetlands, balancing and reducing withdrawal from groundwater resources, implementation of watershed management projects, drainage management and prevent the development of agriculture.

Steps in the stepped spillway by creating an artificial roughening bed, dissipate the flow of energy more than other types of spillways. An increase of roughness leads to a uniform and continuous distribution energy of the flow over the spillway. The present study deals with experimental study regarding the appendance elements on the steps and its impact on the variation of the flow pattern, inception point, energy dissipation and Darcy roughness coefficient Experiments were performed on a physical model, with appendance elements on the steps in different configurations and type (height and notch), and the results were compared with flat stepped spillway. The results showed that the appendance elements on the steps causes some the instabilities and turbulence on the center axis and sides of the steps, which causes the inception point to be moved upstream of the stepped spillway. A nappe and transition flow regimes on stepped spillways with appendance elements occur at lower discharges than flat stepped spillway. With notched, the change of the flow regime on the stepped spillway occurs later than in the height state. Also, the appendance elements on the steps have no effect on the energy dissipation and Darcy roughness coefficient. However, with notched on the appendance elements, their performance is improves and the amount of energy dissipation and Darcy roughness coefficient increases 7. 33% and 8% compared to flat stepped spillway, respectively.

In this study, experimental methods in three general categories based on temperature (Hargreaves-Samani, Blaney-Criddle and Trajkovic), radiation (Jensen-Haise, Abtew and Irmak) and mass transfer (Trabert, WMO and Mahringer) and five different models of Valiantzas method (Val 1-5) by comparison with the FAO-Penman-Mantith (FAO-PM) method as reference method have evaluated. For this purpose, meteorological data of 10 synoptic stations of Mazandaran province in a 15-year period (2004-2018) were used. The results showed that between experimental methods based on temperature, Hargreaves-Samani method with R2 between 0/980 to 0/997, in 60 % of stations (six stations), Trajkovic method with R2 between 0/979 to 0/997, in 30 % of stations (three stations) and Blaney-Criddle method with R2 between 0/984 to 0/994, in 10 % of stations (one station) perform the best performance. Among the experimental methods based on radiation, Jensen-Haise method with R2 between 0/946 to 0/992, in 70 % of stations (seven stations) and Abtew method with R2 between 0/812 to 0/930, in 30 % of stations (three stations) have the best performance. The results indicated under-estimate in estimation of the reference plant evapotranspiration by all three experimental methods based on mass transfer compared to the FAO-PM reference method. In all of the 10 stations investigated, the Trabert method with R2 between 0/812 to 0/984, was more accurate than the WMO and Mahringer methods and was closer to the FAO-PM reference method. All 5 different models of the Valiantzas method have under-estimates compared to the FAO-PM reference method. Valiantzas 4 model in 60 % of stations (six stations), Valiantzas 5 and 2 models in 20 % of stations each one (two stations for each one) provided the best performance.

Infiltration is a key process which can be considered for scheduling, design, management and optimization of irrigation systems. Therefore, it is necessary to choose an appropriate infiltration model to optimize water consumption in agriculture and to study the water cycle on a small and large scale. The purpose of this study was to investigate the sensitivity of the coefficients of Kostiakov, Kostiakov-Lewis and Horton infiltration equations to the simultaneous changes of initial moisture and soil bulk density and its effect on the performance of infiltration equations in different soils. For this purpose, cumulative infiltration data in eight soil textures, three bulk densities including 1. 3, 1. 4 and 1. 5 g / cm3 and five volumetric moisture levels including 0. 1, 0. 15, 0. 2, 0. 25 and 0. 3 was prepared using HYDRUS-1D. In order to represent the effect of the sensitivity of the coefficients of infiltration equations on the efficiency of those equations at different moisture and bulk densities, first the coefficients of the equations are calculated for all infiltration data (fitting step) and then at a specific moisture and bulk density for each soil, the coefficients are calculated and for other moistures and densities were used (evaluation step). Based on the results, sensitivity of the coefficients of infiltration equations with changes of moisture and bulk density from high to low was obtained the coefficient of the Kostiakov equation (ak), the coefficient of the Kostiakov-Lewis equation (akl), the power of the Kostiakov equation (bk), the coefficient of the Horton equation (bh) And the power of the Kostiakov-Lewis equation (bkl), respectively. The mean increase of RMSE of the Kostiakov, Kostiakov-Lewis and Horton equations in the evaluation stage was respectively 3. 25, 34 and 2. 8 times the fitting stage. Therefore, the lowest and the highest sensitivity occurred in the Horton and the Kostiakov-Lewis equations respectively.

Side weirs are one of the most important protective structures upstream of structures such as reverse siphons and underpasses in irrigation and drainage networks. In this research, using laboratory data and numerical solution in free flow mode in the pipe, new relationships based on the critical depth of the upstream flow to determine the discharge capacity of sideweirs in circular channels (pipes) in critical situations and Supercritical is presented. This relationship depends on effective parameters such as P / y1, weir crown height to the depth of flow at the beginning of the weir, flow height over the weir crown to weir height ((y1-p) / p) and critical depth of the flow passing over the weir crown. The results of this study showed that the upstream flow rate in the subcritical flow mode is higher than the supercritical flow mode. Also, the relations provided for calculating the flow rate of side weirs in circular channels are suggested due to having high regression and consistency of computational and observational results for designing this type of side weirs in circular channels.

The agro-hydrologic simulations are subject to varying degrees of uncertainty. In this regard, uncertainty analysis can provide useful insights into the level of robustness of the model outputs. In this study, a hybrid multi-objective uncertainty analysis scheme, GLUE-UPSO, based on strained Monte-Carlo simulations was developed, combining Generalized Likelihood Uncertainty Estimation (GLUE) and Unified Particle Swarm Optimization (UPSO). The developed scheme was used for uncertainty analysis of distributed agro-hydrological modeling with SWAP for a sugarcane farming system with subsurface drainage located at Shoaybiyeh Sugarcane Agro-industrial Company farms, Khuzestan, Iran. The results highlighted the strong nonuniqueness of most of the calibrated parameters and the importance of uncertainty analysis of the SWAP simulations. Strong parameter correlations revealed the need for the simultaneous calibration of the model parameters against diverse calibration data. The 95% prediction uncertainty bands obtained for the model's hydrology (soil water content, water table level, sub-surface drainage outflow), solute transport (soil water solute concentration and sub-surface drainage outflow salinity), and biophysical (leaf area index, cane, and sucrose dry yield) components enveloped 67%-90%, 23%-71%, and 75%-100% of the corresponding observed data (including both calibration and validation datasets), respectively, with an r-factor of 0. 58-1. 34, 0. 43-1. 07, and 0. 70-0. 98. The results of the study indicated the acceptable level of model uncertainty and the capability of the developed framework for simultaneous calibration and uncertainty quantification of model components.

Reducing irrigation losses due to surface evaporation using mulch layer on soil surface can help in maintaining water in the current situation that our country is suffering from water deficit. In this research, the effect three types of mulch layer on evaporation reduction was evaluated on three soil textures (sandy loam, loam and clay loam). For this purpose, a layer of three centimeters mulches (water repellent layer, fine gravel and manure) was placed on the soil surface, and their effect and control (without mulch layers) on the evaporation rate of small lysimeters in Yazd city was investigated. The experiments were performed in a in a factorial experiment with completely randomized design with four treatments and three replications. The results showed that the surface mulch layer significantly decreased evaporation in the mentioned three soils. The maximum evaporation reduction in fine gravel layer compared to the control was 59. 8, 58. 2 and 61. 4% in the sandy loam, loam and clay loam soil, respectively. After fine gravel, the manure was more effective than the water repellent layer mulch in evaporation reduction. The effect of mulches on salinity changes in soil depth was different, so that the lowest amount of salinity was observed in the treatment of fine gravel and manure mulches on the surface of the three soils. Water repellent mulch had less effect on reducing the salinity of topsoil than the other two mulches and more salts were transferred from the depth to the soil surface.

The present study dynamically analyzes the policies of sustainable water resources management based on the security of water, food and energy resources of Nexus with respect to changes in demand resulting from population growth and economic growth over a 20-year horizon using the system dynamics approach. The initial modeling and simulation of the model was performed based on the data of Khuzestan Plain as a large structural unit of water-food-energy resources and according to the continuation of the current situation. Based on the results of Monte Carlo Sensitivity Analysis, the model develops water resources sustainability policy in the form of four policy categories including: water demand management, water supply management, food resource management and energy demand management, as well as combining policies in an ideal system. As a result of simulating the proposed solutions, a combination of water demand management policy and food resource management was selected as the best solution. So that with the development of lands covered by pressurized irrigation network, 16% improvement of irrigation efficiency and 10% modification of cultivation pattern and also 6% reduction of agricultural crop losses in food supply management and also 5% reduction of food demand due to food losses An annual increase of 5% improves crop performance as a selection of sustainable water resources management policies.

Hydrological time-series is a time-dependent hydrological variable that finding the model of changes and predicting is the most important goal of time-series analysis. The purpose of this study is to simultaneously study the characteristics of time series and their prediction and the important parameters of the GEP for high-precision predictions in the training and validation. In this study, groundwater depth time-series of Chamchamal plain station located in Kermanshah province with a 12-year period and mountainous climate and the monthly time-series of Alaska temperature with a 50-year period and cold and dry climate have been used. Genexprotools5. 0 software has been used to model time-series by GEP. The results of studying with GEP showed that the periodicity of data properties that existed in the time series of temperature caused correlation results above 90% in different stages of training and validation. So that the effect of different parameters of GEP is less than 10% in improving results. On the other hand, by examining the time-series of groundwater depth, which lacks periodicity and has a descending ACF shape, the prediction results of the GEP with any effective expression parameter, R more than 44% in the validation wasn't obtained. This means that the time-series preprocessing has a greater impact on the prediction results. So that by eliminating the semester, the prediction results in all stages of modeling are significantly reduced. In this case, the best R for the validation is 50%.

Various methods have been developed to estimate the Manning roughness coefficient, of which the inverse method is widely used. This study aimed to estimate the inverse of Manning roughness coefficient using the WinSRFR model and estimating infiltration parameters of Kostiakov-Lewis equation in furrow irrigation and to investigate their variations in different irrigation events. For this purpose, two inflow discharges (average 0. 27 and 0. 53 liters per second), two irrigation cycles (5 and 10 days), two fields with different soil texture (E and F) in three irrigation events (first to third) were considered in three replications. Model error in estimating advance and recession time, and volume of infiltrated water was investigated using statistical indices including RE, RMSE and NRMSE. The values of these indices in estimating the advance time in the field E were 0. 44%, 0. 21 min and 1. 11% in the total three irrigation events, respectively. Also, the values of these indices were 1. 58%, 5. 25 min and 2. 78% in the recession time and 0. 59%, 5. 5 liters and 0. 50% in the volume of infiltrated water, respectively. There was less error in estimating the advance and recession time in the field F which showed the excellent accuracy of the inverse estimation method using the WinSRFR model in determining the Manning roughness coefficient. The results also showed that in the field E, the minimum and maximum values of Manning roughness coefficient were estimated as 0. 017 and 0. 34 and on average 0. 075 in the total three irrigation events, respectively. In the field F, the minimum, maximum and the average values of Manning roughness coefficient in three irrigation events were 0. 015 and 0. 09 and 0. 041, respectively.

AquaCrop model is one of the water-driven models that has been developed to simulate the growth of crops under different amounts of irrigation water. However, to use this model, it is necessary to perform calibration. For calibration, it is necessary to determine the sensitivity of changing in input parameters. Therefore, the present study performed to evaluate the sensitivity of AquaCrop in simulating safflower biomass to changes in crop growth parameters. So, normalized water productivity (WP*), maximum transpiration coefficient (KcTrx), initial canopy cover (CC0), crop growth coefficient (CGC) and crop reduction coefficient (CDC) was evaluated using Baven method. In this study, data collected from an agricultural research station in Kermanshah, Iran, was used. Data consisted of surface drip irrigation at three levels (T1, T2 and T3 represent the supply of 100, 66 and 33% of water requirement, respectively), furrow irrigation at two levels (T4: 100% water supply and T5: application of 50 mm irrigation water at the same time in flowering period) and rainfed (T6). The results showed that AquaCrop was the most sensitive to change WP*. The lowest sensitivity was assigned to CDC. The sensitivity of this model to CDC parameter changes was negative and for other treatments was positive. Therefore, increasing the amount of CDC decreased safflower biomass while increasing other parameters increased safflower biomass. The sensitivity of each parameter depended on the irrigation treatment. So that increasing the amount of irrigation water for WP* and Kc increased the sensitivity.

Due to the scarcity of water resources in agriculture, improving the irrigation management of potato fields can reduce applied water and increase the productivity of this important crop. For this purpose, it is necessary to have sufficient and accurate information about the status of applied water and water productivity in the conditions of farmers' management. Therefore, the amount of water applied and water productivity in the conditions of farmers' management of the three major potato production areas in Fars province were investigated. Three areas of Abadeh, Eghlid and Khorrambid and three systems of surface, sprinkler and drip irrigation were considered as experimental treatments. T-test was used for statistical comparison of the results. The correlation between different factors was examined by determining the correlation coefficient. Results showed that the differences in applied water, yield and water productivity in different regions were not significant at the level of 5%. The average yield and water productivity were 43. 6 tons/ha and 4. 87 kg/m3, respectively. The use of sprinkler and drip irrigation systems reduced the applied water by 1100 cubic meters per hectare, increased the yield by 10. 5 tons per hectare and increased productivity by about 1. 8 kg/m3. However, these differences were not statistically significant at the 5% level. The average amount of water used in potato fields was 9420 m3/ha, which was 3350 m3/ha less than the average required water. If irrigation is based solely on the farmer's experience and irrigation scheduling is not considered, there may be no difference between applied water in different irrigation systems and the water supplied may be less than required. Therefore, in order to reduce the effects of water stress, increase crop and water productivity, in addition to the irrigation system, serious attention should be paid to field irrigation scheduling and volumetric water delivery.

Drought and water scarcity in Iran is a climatic reality, and given the increasing need of different sectors for water, the problem of water scarcity in the coming years threatens the sustainability of cultivating some strategic crops with high irrigation water requirement. Rice cultivation requires high irrigation water and regarding water resources scarcity in Iran, the best way to save water is to improve water productivity. In this regard, in the present study, the estimation of rice water productivity indices i. e. crop per drop, benefit per drop, and net benefit per drop was done in four major rice producing provinces of the country, including: Guilan, Mazandaran, Khuzestan, and Fars provinces. This study uses cross-sectional data from 2014-2015 rice production cost plan of Ministry of Jihad-e-Agriculture collected by cluster sampling from each province's farmers and estimated water requirement through remote sensing to calculate water productivity indices. The results showed that Mazandaran and Guilan provinces had the highest water productivity (yield/water requirement) with average of 0. 99 and 0. 88 kg/m3, respectively, Fars and Khuzestan provinces were in third and fourth places with averages of 0. 65 and 0. 52 kg/m3, respectively. The results showed that the highest net benefit of water consumption were in Guilan and Mazandaran provinces with averages of 9310 and 6590 Rials/m3, respectively. According to the results of this study, it is recommended to limit rice cultivation in Khuzestan and Fars provinces, especially in years with water deficiency.

Investigation of ecological, hydrological and habitat suitability status of aquatic communities is one of the key elements in river ecosystem management. In this regard, in the present study, the determination of the minimum environmental flow of Liqvanchay River using hydrological method of Tennant based on hydrological Information and estimation of ecologically optimal water requirement using Habitat Simulation Model as well as hydromorphocological analysis and habitat suitability of index fish Salmo trutta L. 1758 were investigated. For this purpose, mesohabitat simulation based on curves habitat suitability index were performed by field studies and sampling of hydraulic (depth, velocity and bed index) and ecological parameters and accordingly, a new method of classifying the ecological flow regime according to the echohydraulic indices of habitat suitability (water depth, flow velocity and bed) was considered. First, the geometry of the Liqvanchay River model and cross sections was created using the topography map of Liqvanchay River and Arc-GIS software. Then the hydraulic simulation of the river was performed with HEC-RAS software. In the next step, hydromorphocological and habitat simulation were performed in MesoHABSIM model. In this Echohydraulic Model, the relationship between the hydraulic flow and the habitat needs of the species Salmo trutta was established by Weighted Usable Area, and the discharge-habitat suitability curves of the target species were extracted in different discharges in both adult and juvenile life stages. By extracting the discharge-habitat suitability curve, the desirability of the river in terms of quantity and location was investigated. The results showed that the optimal ecological flow velocity should be in the range between 0. 27 to 0. 76 m/s and the ecological water depth should be in the range between 0. 3 to 0. 7 m in different seasons and parts of the river. According to the calculations, the range of the Optimal Ecological Flow regime to the habitat needs of the indicator Salmo trutta in the studied river is between 0. 27 to 2. 84 m3/s in October and May, respectively. Also, the research findings showed that the ecological needs of the indicator species for biological activities of growth and spawning are provided only in two seasons of winter and spring and in the upper and middle periods of the river. According to the results of this study, the distribution of habitat suitability along the ligvanchay river, under the influence of geometric, hydraulic parameters and flow rate, indicates the suitability habitat conditions of of Salmon trutta species in the upstream area and poor habitat conditions in the downstream area.

Limited water resources and the need for better water management indicate the importance of precisely determining the applied water of crops and orchards. In this study, applied irrigation water and physical and economical water productivity of wheat were evaluated in Ahwaz and Dasht-e-Azadegan in Khuzestan province. Discharge of flow was measured in each irrigation event using WSC flumes in the randomly selected farms with blocked-end border irrigation method. Results showed that the average applied water in selected farms in Ahwaz and Dasht-e Azadegan were 4837 and 5605 m3/ha, respectively. According to wheat yield for each studied farm in these two regions, the average of water productivity was 1. 06 and 0. 89 kg/m3, respectively. Net economic water productivity for Ahwaz and Dasht-e-Azadegan were 4756 and 5377 IRR/m3, respectively. Due to setting up and operating costs of the pump, which increases the cost of irrigation operations in farms equipped with pump stations on river water resources, the number of irrigation rounds and irrigation depth in each irrigation round decreased and increased, respectively, relative to farms irrigation canal water resources. Comparing physical, gross, and net economic water productivity showed 15. 7, 28. 5, and 67. 6 percent increase in pump station farms relative to canal farms.

The emitter clogging by crop roots is a main problem for using subsurface drip irrigation system in an arid area under water stress condition. The goals of this study were to investigate the effect of treflan injection for preventing of emitter clogging by grass roots in subsurface drip irrigation (SDI) and the effect of these treflan on the visual quality of two grass species. The experiment was conducted in a factorial experiment according to completely randomized block design with three replications from 2012 to 2013. The experiment included three levels of treflan contain 0 (C0), 100 (C1) and 300 (C2) mg net Treflan per emitter per year, and two grass species of Festuca (F) and Brmudagrass ( B). The results showed that the injection of Treflan into SDI system decreased roots around the emitter outlet and consequently no emitter clogging was observed. Root penetrate and severe clogging problem was more for Brmudagrass in compared to Festuca. The results showed after two growing seasons there was no emitters clogging in high Treflan level injection. Also, increasing the concentration of treflan up to 300 mg per year per emitter had not effect on the visual quality of grass species. Due to the importance of environmental protection, it is recommended to use a high-tech emitter and dripline for subsurface drip irrigation with no or lower herbicides injection to prevent clogging of the emitter.

Water shortage, salinity and nitrogen deficiency are the most important factors limiting plant production in arid and semi-arid regions. However, over-irrigation and over-consumption of nitrogen fertilizers can also limit crop growth and yield. The aim of this study was to evaluate the effects of salinity of irrigation water in interaction with different levels of irrigation water and nitrogen requirements on growth characteristics and water use efficiency of spinach. A combination of five salinity levels (1, 4, 7, 9 and 11 dS/m) with three levels of water requirement including (75, 100 and 125% of irrigation water requirement) and four levels of nitrogen from the source of urea with a purity of 46% (0, 100, 150 and 200 mg/kg soil) under controlled greenhouse conditions in three repetitions were considered as the studied factors. The results showed that salinity in combination with water stress and nitrogen deficiency caused a significant reduction in plant growth. Yield in treatments 75 and 125% of water requirement was 22. 7 and 10. 8% less than 100% of water requirement, respectively. Salinity in the treatment of 75 and 100% water requirement had a significant effect on leaf area index,such that the treatment of 75% of water requirement with the salinity level 11 ds/m decreased the leaf area index 46% toward control treatment. By increasing the application of fertilizer at the optimal level of 150 mg N/kg soil, plant growth and yield for all salinity levels showed a significant increase. Water use efficiency increased in W1, W2 and W3 treatments at salinity levels 4, 7 and 4-7 ds/m, then decreased significantly with increasing salinity for all treatments of water requirement and nitrogen levels. Also, 125% treatment caused a further reduction in water use efficiency compared to 75% and 100% water requirement treatments for all salinity levels. Finally, the best treatment in terms of water use efficiency was observed in the treatment of 75% of water requirement at moderate salinity levels (4-7 dS/m).

Water scarcity is one of the limiting factors for agricultural production in arid and semi-arid regions of the world. Being located on a major global dry belt, many parts of Iran tend to experience frequent fluctuations in precipitation levels. Under these conditions, it is necessary to make the best use unit volume of water. To achieve the maximum possible water use efficiency in agriculture, the plants should be given just enough water to reach an acceptable crop yield. This study investigated the effect of deficit irrigation on wheat yield in the Bardsir plain of Kerman, Iran, in the crop year 2019-2020. The experiment was performed in Randomized Complete Block Design (RCBD), using 4 treatments and 3 replications, 100, 85, 70 and 60 percent of water irrigation requirements were considered as 4 different treatments. The highest crop yield was observed in the treatment with 100% irrigation and the highest water use efficiency was achieved in the treatment with 15%deficit irrigation. Therefore, to maximize the water efficiency of wheat production in the Bardsir region, wheat farms in this area should receive water in amounts equivalent to 85% of their irrigation water requirement.

The possibility of modification the saline lands by planting the salt-resistant crops, prevents the production of wastewater and drainage costs. In this study, the possibility of modifying saline soils by planting barley at different irrigation levels and soil salinity, was investigated. Salinity treatments included 6(S1), 9. 5(S2) and 13(S3) (dS. m-1) and irrigation treatments included the amount of 100(I1), 75(I2) and 50(I3) percent based on the barley water requirement. This research was done as a factorial experiment in a completely randomized design with three replications. Due to increasing soil salinity (from S1 to S3) at irrigation levels of I1, I2 and I3, the amount of evapotranspiration was reduced to 25. 5, 30. 6 and 36 percent, respectively. The amount of reduced soil salinity in S1, S2 and S3 treatments were equal to 4. 34, 6. 88 and 9. 42 (in I1 treatment), 3. 76, 4. 92 and 6. 08 (in I2 treatment) and 3. 64, 3. 58 and 3. 52 dS. m-1 (in I3 treatment), respectively. Low irrigation reduced the soil modification efficiency. Also, increasing the soil salinity in low irrigation treatments had a high effect on this work. Due to drought stress, the amount of soil modification efficiency decreased to 16% (in S1 treatment), 48% (in S2 treatment) and 62. 6% (in S3 treatment). However, at full irrigation level, increasing the soil salinity (up to S3 treatment) did not had effect on the soil modification efficiency. Regression functions were used to estimate the final soil salinity, by the initial soil salinity and irrigation level. The exponential model had the best fit between the two variables of EC_f/EC_i and I_i/I_1. The overall result showed that achieving to the highest soil modification efficiency and optimal modeling, required to the full irrigation of the crop.

Conceptual rainfall-runoff (RR) models are one of the simple and efficient tools in hydrological modeling. These models simulate the flow regime using mathematical equations using input data such as precipitation, evapotranspiration and measured temperature, and basin topographic information. Calibration of RR models, e. g. WetSpa which has been developed in Belgium, is a process in which parameter adjustment are made so as to match the dynamic behavior of the RR model to the observed behavior of the catchment. This research presents an application of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) and Black Widow Optimization (BWO) for multi-objective calibration of WetSpa in Gorganroud river basin, Iran to optimize 11 global parameters of the WetSpa model. The objective functions are Nash–, Sutcliffe and logarithmic Nash–, Sutcliffe efficiencies in order to improve the model's performance. The WetSpa model then was applied for a period of 1-year flood simulation in the basin and the results were analyzed. Results showed that the evolutionary NSGA-II and BWO algorithms are capable of locating optimal parameter sets in the search space. The measured correlation coefficient in the calibration process was 0. 69 and 0. 81 for the NSGA-II and BWO algorithms, respectively. Moreover, a sensitivity analysis was conducted on the global parameters in which the surface runoff coefficient was the most sensitive parameter of the model.