Iranian Journal of Soil and Water Research
Year:2021 | Volume:52 | Issue:1|Papers Count:20

Due to the increasing development of nanotechnology, its use has increased in all fields, especially in the field of environmental pollution as an absorbent. For this purpose, a factorial experiment was conducted in a completely randomized design with two factors; arsenic factor at four levels (0, 25, 50 and, 100 mg/kg) and TiO2 factor at three levels (0, 0. 25 and, 0. 5% by weight) and three replications in the laboratory and in a dark room at 25˚ C for 8 months using the 1. 3 L respiratory jars. Cumulative respiration percentile results showed that the highest respiration control treatment matched with 50 mg/kg arsenic plus 0. 5% TiO2 (w/w). The highest and the lowest respiration rates were obtained in the first and eighth months of incubation, respectively, with control and 25 mg/kg arsenic with a difference of 33. 78%. As the nanoparticle levels increased, the respiration rate increased, so that the highest respiration rate was obtained in the first month of 0. 5% TiO2 treatment. The highest and the lowest MBC, as well as qmic, was obtained in 100 mg/kg arsenic treatments plus 0. 25% TiO2 (w/w) and 50 mg/kg arsenic plus 0. 5% TiO2 (w/w), respectively. Conversely, the highest and the lowest qCO2 were obtained from 50 mg/kg arsenic plus 0. 5% TiO2 (w/w) and 100 mg/kg arsenic with 0. 5% TiO2 (w/w), respectively. Cluster analysis of the variables showed that the MBC and qmic variables were the first cluster and the second, third, and fourth clusters were the BR, qCO2, and cumulative respiration, respectively. According to the results of this study, the application of 0. 5% TiO2 (w/w) can reduce the toxic effects of arsenic and improved BR, cumulative respiration rate, and monthly respiration.

Saline and sodic soils have a poor structure. The chemical and physical properties of these soils can be modified using various modifiers. Consumption of organic modifiers increases aggregate stability, soil water holding capacity and percentage of usable moisture for the plant. The use of water-soluble polymers and fertilizers containing humic acid is suitable for reducing water use in agriculture and improving soil structure in saltaffected soils. The purpose of this study was to investigate the effect of polyacrylic and humic acid on aggregate stability and field capacity in saline and sodic soils. This study was conducted using four salinity levels of 10, 20, 30 and 40 dSm-1 and application of two modifiers (humic acid and polyacrylic acid) at 4 levels (0, 0. 2, 0. 4 and 0. 8% by weight) in factorial arrangement with completely randomized design with three replications in greenhouse conditions. The results showed that the highest values of aggregates stability were at the salinity level of 10 dSm-1 and the level of 0. 8% polyacrylic acid (3. 13 mm) and humic acid (1. 51 mm), respectively. The highest moisture content of the field capacity was measured at the salinity level of 40 dSm-1 and at the level of 0. 8% polyacrylic acid (26. 65%) and humic acid (25. 65%), respectively.

Heavy metals affect the dynamics of organic carbon by contaminating soil and altering its chemical and biological properties. For this purpose, a split factorial experiment was conducted with three replications. Experimental factors included Antimony at four levels (0, 25, 50, and 100 mg/kg), TiO2 nanoparticles as an adsorbent at three levels (0, 0. 25, and 0. 5 % by weight), and time at eight levels (the first month to the eighth month). Results showed that the basal respiration decreased from the first month to the eighth month of incubation and the highest basal respiratory rate was obtained from the first month of incubation and the lowest one was belong to the eighth month of incubation with a significant difference of 27. 81%. The highest and the lowest organic matter degradation rates were obtained in control and 50 mg/kg antimony without nanoparticle application with 16. 57% difference. By increasing antimony levels, the rate of degradation of organic matter decreased sharply, but by increasing the levels of contaminant, the application of 0. 5 % (w/w) nanoparticles caused to increase the rate of organic matter decomposition. The highest value of half-life and mean residence time of carbon in the soil were obtained from 50 mg/kg without adsorbent treatment and the lowest value was obtained from 25 mg/kg with 0. 5% (w/w). According to the results of this study it can be stated that the application of 0. 5 % (w/w) TiO2 adsorbent increased the rate of decomposition of organic matter but decreased the half-life and mean residence time of carbon in the soil. At the higher contaminant levels (100 mg/kg of antimony), compared to the lower levels (50 and 25 mg/kg), the adsorbent surface lost its efficiency because of saturation with the contaminant, therefore for higher level of contaminant application, higher level of adsorbent (more than the 0. 5% (w/w) TiO2) should be used.

In this research, a three-dimensional numerical model has been developed to simulate the flow pattern at lateral intake in 180-degree bend. Due to the curvature of flow boundaries and computational grid, the threedimensional Navier-Stokes equations are solved in nonorthogonal and nonstaggered curvilinear coordinates, and given the complexity of the flow conditions, the k-ω model for low Reynolds numbers is used to solve turbulence terms. The equations are discretised by the finite volume method and the central difference and power law algorithm are used to discretise the diffusion and convection terms, and the stable semi-implicit (SIMPLEC) is used to couple the flow and pressure field. Also, to increase the efficiency of the model, one block with variable domain has been used to simulate both channels (main and intake). The developed model was first validated in two tests of flow in 180-degree bend and the lateral intake in a straight flume. Then flow pattern at the lateral intake in 180-degree bend for 45-degree diversion angle in the establishment angle of 40degree was simulated and compared with the available laboratory data. The average modeling error in the main channel and intake was about 7. 3% and 19. 7%, respectively, which is acceptable compared to the results of other commercial models.

One of the basic elements of water resources management and increasing agricultural productivity is the optimal use of (water) resources. The water footprint index is one of the new approaches used for this purpose. In this study, the water footprint approach was used to optimize the cultivation pattern of crops in different climates of Iran. For this purpose, 11 crops were selected in six different climates of Iran and after calculating the water footprint of the cultivated crops, the RIS indicators and the actual blue water footprint (WFAblue) were evaluated. After evaluating and calculating the indicators, the TOPSIS optimization method was used to provide the optimal cultivation pattern. Results showed that among the proposed products, wheat, barley, alfalfa, cotton, and tobacco had the highest amount of green water footprint, of which the highest one was corresponded to the PH-C-W climate. However, the highest blue and gray water footprint are mainly related to rice, beans, cotton and tobacco, which is due to the high water consumption of these products (high water demand). Evaluation of the optimization model also showed that the most optimal crops for cultivation in the region were respectively corn with 39%, barley with 23%, potato with 20%, tomato with 7% and wheat with 1% priorities. The most undesirable crops for cultivation in the provinces of the country were respectively, tobacco, cotton, beans, rice, sugar beet and alfalfa.

In this research, experimental evaluation of different hydraulic conditions on the performance of gabion sill in dissipating energy at downstream of Ogee spillway has been investigated. The parameters evaluated in this study included: Froude number, sill height, the amount of opening in the sill width and the diameter of the aggregates. The experiments were conducted by using flow discharges of 20 to 40 liters per second with two heights of 5 and 10 cm and openings of 10, 15, 20 and 30 cm in fixed sill widths with and without openings. The results showed by increasing the height of the sill, the relative length of the hydraulic jump increases and the amount of relative energy dissipation also increases. Also, by increasing the diameter of aggregates, the relative length of hydraulic jump and the amount of relative energy dissipation decreased. The highest amount of energy dissipation was related to aggregates with an average diameter of 1. 5 cm in which the amount of energy dissipation and the length of hydraulic jump were 9 and 8. 3 % more than the ones in 3 cm diameter of aggregates, respectively. The results also showed creating an opening and increasing it across the sill reduces the relative energy dissipation. So that the relative energy dissipation in the gabion with 30 cm opening was about 7% and its relative hydraulic jump length was about 9% less than the ones in sill without opening.

One of the important hydraulic issues is to study the effect of additional structures on dissipating the flow energy in overflow structures such as drops. In the present study, using a laboratory model, the effect of simultaneous use of horizontal screen and gabion in the inclined drop structure was investigated and compared with the results of other researchers. The experiments were performed for two heights and three inclined gabion angles, two screen porosity ratios and a flow rate of 150 to 800 liters per minute. The results of all the studied models showed that by increasing the relative critical depth, the relative energy consumption values decrease and the relative downstream depth increases. By increasing angle and height of the slope and decreasing the porosity of the screen for a constant relative critical depth, the relative energy dissipation of the inclined gabion drops equipped with a horizontal screen increases. Increasing the wetted length of horizontal screens causes two-phase flow and air entrance to the used system and consequently the amount of energy dissipation increases. Simultaneous use of gabions in the sloping section and horizontal screens at the edge of the drop has significantly reduced the downstream Froude number so that the downstream Froude number at all three angles and two porosity ratios decreased from range of 4. 49-35 to range of 1. 31-2. 48 compared to the simple inclined slope and from range of 1. 48-5. 78 to range of 1. 31-2. 48 as compared to the inclined slope equipped with a horizontal lattice plate.

In this research, a special form of nonlinear weirs called piano key overflows has been studied. In this type of weirs, unlike congressional weirs, the openings are sloping inwards and outwards one by one. so this study was conducted with the aim of laboratory study of the discharge coefficient of the arched piano key in the plan in free flow conditions. In this research, 27 models of arched piano key overflow structures with three arc lengths of 1. 20, 1. 40, 1. 60 m, three crown lengths of 5. 10, 4. 30, 3. 20 m and three crown heights of 0. 30, Made 0. 20, P = 0. 15 m. All models were made of glass with a thickness of 10 mm. The models were compared in terms of height effect, key width ratio and arc effect under the same effective length conditions. The results showed that increasing the flow rate and consequently increasing the dimensionless ratio, leads to a decrease in watering coefficient and in fact has the opposite effect on the permeability coefficient of piano switch weir in free flow. Also, by increasing the dimensionless ratio, the flow currents from the output switch interfere with each other, and as a result, due to the local immersion, the overflow coefficient of the overflow of the arched piano switch in the free flow decreases. The arc model with an arc length of 1. 40 m with 1. 27 had the highest and the arc model with 1. 20 m and 1. 22 had the lowest permeability coefficient in free flow. Finally, it was found that the arc model has a higher permeability coefficient than the direct model, which indicates the positive effect of the arc. Also, in order to estimate the permeability coefficient of free flow and Q flow rate, relationships were provided for the overflow of the piano switch in the arc position.

Considering the effective role of soil fertility in advanced agriculture, preparing soil fertility map for better planning and achievement of specific management on based soil spatial variability seems necessary. The purpose of this study was to prepare a soil fertility map for rice, based on the effective parameters on soil fertility including organic carbon, total nitrogen, available phosphorus and potassium, clay and cation exchange capacity by integrated AHP with two types of Kandel and S-shaped fuzzy membership functions. For this purpose, soil samples were collected in 50 observation points and their physical and chemical properties were measured. Interpolation of these points for the studied parameters was done by kriging method. Then the fuzzy map of each parameter was prepared by defining the S-shaped and Kandel membership functions and weighted using AHP method. Finally, by integrating them in GIS environment, soil fertility map was prepared for rice. Fertility maps obtained from S-shaped and Kandel membership functions showed that 95. 73% and 53. 68% of the studied area have high and very high fertility, respectively. Comparison of fertility maps through resampling points to control the accuracy of the maps showed that the fertility map resulting from S-shaped fuzzy membership function (64%) is more efficient and realistic than Kandel membership function (40%). Therefore, the integration of AHP with the S-shaped fuzzy membership function can quantify and classify the soil fertility of the studied area and be useful for managing fertilizer use and monitoring soil nutrition changes.

he present study was performed to investigate and compare some physico-chemical properties, clay mineralogy and different forms of potassium (K) of paddy soils with non-paddy soils and to study the effect of waterlogging on soil pedogenesis in some important paddy areas in Fars province. For this investigation, a paddy and non-paddy soil pedons within each area with similar calcareous parent materials and landform were dug and some soil properties and different forms of K in surface and subsurface soils were determined. The results showed that the average contents of soluble, exchangeable, HNO3-extractable, structural and total K in the non-paddy soils were 3. 5, 199, 864, 4635 and 5502 mg kg-1; and in the paddy soils were 2. 5, 164, 742, 5346 and 6088 mg kg-1, respectively. Results also indicated that the paddy soils had lower contents of soluble, exchangeable and non-exchangeable K due to the K leaching by irrigation water and removal by plant uptake. Significant correlations were found between different forms of K and some soil properties like clay, CEC and OC. The results of clay mineralogy indicated similar minerals, including smectite, illite, chlorite, palygorskite, vermiculite and kaolinite but with different relative abundance. Long-term rice cultivation seems to affect only the amount of clay minerals and converts illite and palygorskite to smectite. Significantly possitive correlations were found between non-exchangeable, mineral and total K with illite content in the clay fraction.

Soil evolution is affected by both parent material and topography as the two main factors of soil formation. This study was conducted to compare the effect of marl and calcareous parent materials in different slope positions, including the summit, back-slope, foot-and toe-slopes on soil development using evolutionary indicators along two topo-sequences in the Karoon 3 Basin, east of Khuzestan Province. Accordingly, four soil profiles in each of the two topo-sequences were dug and sampled based on their genetic horizons and properties including Fed, Feo, Fep and the magnetic susceptibility at 0. 46, and 4. 6 kHz frequencies were measured. The results showed that pedogenic iron (Fed) was higher for both parent materials in all slope positions at subsurface horizons as compared to those at the surface horizons. The results also showed that with increasing soil depth, especially in developed horizons such as Btk, the Fed-Feo index increased. In addition, the Feo/Fed ratio in all slope positions showed a decreasing trend with depth. The results also showed that the lowest χ LF value corresponds to the C horizon in all slope positions in both the parent materials. The amount of χ LF showed a positive and significant relationship with the clay contents of the soils. Still, no meaningful relationship was observed with the calcium carbonate content of the soils. The higher value of χ fd index at the soils developed on the marl parent materials (in all slope positions) compared to those of the calcareous parent materials indicates more weathering in these soils than their corresponding soils in calcareous parent materials.

Increasing water productivity in agricultural sector is necessary, since this sector is the largest consumer of water in Iran. Because of higher irrigation efficiency, in particular, the reduction of losses of deep percolation and evaporation from the soil surface, drip-tape system is a good option for irrigation. Additionally, using varieties of a crop having high yield is another way to increase water productivity. The objective of this study is to investigate the crop yield and irrigation water volume and to estimate the physical and economical water productivity for different hybrids of maize by drip-tape irrigation. Field experiments were conducted at the research farm of the Agricultural and Natural Resources College of the University of Tehran, in Karaj in 2017. The treatments were nine hybrids of maize (BK42, KSC400, KSC260, BK65, KSC600, BK50, BK74, Barekat3 and KSC704). The results of this study showed that the type of hybrid had a significant effect on crop yield and water productivity. Generally, among the examined varieties, the BK65 hybrid had the highest biomass production (19. 54 ton/ha) and biomass water productivity (3. 43 kg/m 3 ), and the lowest yield (10. 55 ton/ha) and grain water productivity (1. 62 kg/m 3 ). Additionally, the KSC600 hybrid had the highest grain yield (13. 86 ton/ha) and grain water productivity (2. 12 kg/m 3 ) compared to other hybrids. The reason for the high biological performance of BK65 hybrid compared to other hybrids was the higher growth of vegetative part related to reproductive part. The BK42 and KSC260 hybrids had the lowest yield and productivity.

Estimating actual evapotranspiration in river basins is necessary to use water resources optimally and to improve river basin management. SWAT hydrologic model and SEBAL remote sensing algorithm are among the known methods which have addressed this issue. In the present study, in the first step, the actual evapotranspiration of Karkheh river basin was estimated in dry, normal, and wet years (2008, 2012, and 2015, respectively), using the SWAT model calibrated based on runoff and crop yield and SEBAL algorithm. SWAT model was calibrated and validated using six hydrometric stations for the periods of 1993-2009 and 2010-2013, respectively, in which the 𝑅 2, NS and RMSE values were obtained between 0. 45 to 0. 7, 0. 52 to 0. 67 and 12. 64 to 25. 02 (m 3 /s) for the calibration period and between 0. 4 to 0. 6, 0. 3 to 0. 56 and 11. 08 to 23. 17 (m 3 /s) for the validation period, respectively. Further, the average observed and simulated yield of the strategic crop (wheat) in the basin were equal to 4. 70 and 5. 01 (ton/ha), respectively. In addition, the results of SEBAL algorithm and SWAT model were compared together based on the water year status, which the correlations between the results of those methods were equal to 0. 74, 0. 60, and 0. 52 for normal, dry, and wet years, respectively. In the second step, based on the ground data and MODIS, which has a suitable temporal resolution, and OLI which has a suitable spatial resolution, the results of SEBAL algorithm and the variation ranges of main parameters are presented for Pole-dokhtar and Ravansar plains. Ravansar plain has more cultivation areas and lower topography changes compared to Pole-dokhtar plain. The simulation of crop yield by SWAT gave a better result in Pole-dokhtar plain. Based on the results of this study, the values of evapotranspiration obtained from SEBAL algorithm and SWAT model can be reliable and close to the actual values of evapotranspiration in the river basin.

Estimation of sediment transported by the streamflow is important for planning and storing water resources of dam reservoirs and river bed changes, watershed management, coastal protection and the environment. Sediment transport in the river is an inherently uncertain and complex phenomenon. Incomplete knowledge of processes and data create uncertainty in estimating sediment transport. Parameters uncertainty is one of the main sources of uncertainty in estimating the suspended and bed sediment load. In this paper, the Monte Carlo (MC) simulation method is used to estimate the uncertainty of suspended and bed sediment load due to uncertainty in the parameters of the support vector machine (SVM) model in the Karaj Dam Basin. The partial mutual information (PMI) algorithm was used to select the efficient input variables in the SVM model to estimate the suspended and bed sediment load. The results of using PMI algorithm show that the only efficient variable in estimating the suspended and bed sediment loads is the current stream discharge. The results show that the uncertainty in estimating the suspended sediment load with SVM model for training, test and total data is equal to 12. 8%, 17% and 13. 5%, respectively. Also, the uncertainty in estimating the bed sediment load with SVM model for training, test and total data is equal to 23. 5%, 36. 8% and 27. 2%, respectively. Therefore, the uncertainty in estimating the bed sediment load with SVM model is more than the one in estimating the suspended sediment load. Therefore, the use of optimization methods can be useful for accurate estimation of parameter values and reducing uncertainty in estimating the suspended and bed sediment load.

One of the main challenges associated with the development of irrigation systems and other water distribution systems is the sediment removal from the inlet channel. Vortex settling basin (VSB) is one of the types of sediment extractors with small size and high efficiency which removes the sediments using the vortices of the flow. Studies on the proper design of VSBs are generally based on experimental and physical models which are highly costly and time-consuming. In this study, SSIIM model was evaluated for the simulation of flow field and sediment distribution in a VSB and the results were compared with experimental measurements. After ensuring the relative agreement of the model results with experimental measurements, the effect of different design parameters such as inlet sediment size, bottom outlet discharge ratio, and bed level difference between inlet and outlet channels were investigated. The results showed that among the design parameters, trap efficiency of the VSB is more sensitive to the sediment size. By increasing the bottom discharge ratio, the efficiency increases, but this increase in the efficiency barely exceed 4 % for bottom discharge ratios higher than 10 %. In addition, increasing the bed elevation difference between the inlet and outlet channels can increase the efficiency up to 18 % for fine-grained sediments, while this increase is less than 10 % for coarse-grained sediments.

The application of biochar in the soil in order to improve soil quality and also waste management, has received considerable interest in recent years. Success of such management requires expert knowledge about the impact of a given biochar on soil and plant properties, before its field application. For this purpose, the effect of five different levels of biochar (0, 1, 2, 3 and 5% w/w), produced from residual of pistachio, on growth and water productivity of maize plants in a sandy and a silt loam soil was investigated. The study was performed in 2018 as a greenhouse experiment with a completely randomized design. The results showed that the effect of biochar on plant growth is strongly soil dependent. The biochar application had a negative effect on the growth of maize in the sandy soil. Root and shoot dry biomass as well water productivity were reduced more than 90% by application of 2 and 3% of biochar as compared to the control (0%), and the plant growth was hindered by further increase of biochar (at 5%). Consequently, water productivity was also reduced significantly. This negative effect of biochar application in sandy soil was attributed to an induced salinity as a result of biochar application and the low water holding capacity of the soil. In contrast, the effect of biochar on salinity of silty loam soil was not remarkable and only at application rate of 5%, it was increased significantly as compared to the control. Although the application of biochar in silty loam soil did not show a significant effect on root biomass, plant height, and chlorophyl index but shoot biomass and water productivity were increased till the application rate of 2% compared to the control. In conclusion, the results showed that i) one should be cautious with application of biochar (originated from pistachio residual) in coarse-textured soils, ii) and also the efficient application rate of each biochar should be determined in each soil before its application.

Groundwater quality management planning is based on spatial distribution of the effective parameter in aquifer pollution. In this study, different interpolation methods in Babol-Amol shallow aquifer were evaluated according to its hydrogeological characteristics. After initial data processing, 21 deterministic and geostatistical interpolation methods with linear and nonlinear relationships including inverse distance weighted (IDW), ordinary kriging (OK), lognormal ordinary kriging (Log_OK), disjunctive kriging (DK), empirical Bayesian kriging (EBK), natural neighbor (NN), trend surface (TS) and Spline were compared in order to select the most suitable interpolation method. The total dissolved solids (TDS) parameter was used in Babol-Amol coastal shallow aquifer near the Caspian Sea in north of Iran. The seven error criteria were used for verification in cross-validation of all sampling wells. The results indicated that the nonlinear Log_OK method produced better results in Babol-Amol aquifer with 71. 43 percentage of error criteria. Therefore, it can be concluded that the non-linear Log_OK method had promising performance in shallow aquifers based on their hydrogeological characteristics.

Sharp crested weirs are one of the most important structures in the river intake and are the most common instruments for measuring the intensity of flow in open channels, which are widely used in water transmission systems and irrigation and drainage canals to regulate water levels and floods. One of the types of sharp crested weirs is angular weir, in which by increasing the effective length of the crown, more discharge is allowed to pass with less head, resulting a higher efficiency and consequently a reduction in irrigation system costs. In this study, 165 existing laboratory data obtained from two flumes with widths of 0. 5 and 0. 52 m and with seven ratios of weir length to flume width (L/B) of 1. 14 and 3. 86 and six weir crown heights of 0. 10 m to 0. 506 m were used in free flow conditions. In this study, the critical depth of flow passage over the weir crown was used to calculate the flow rate. Also, a new function was developed to calculate the flow rate directly and without the need for flow coefficient by presenting the geometric coefficient of the weir, including all the geometric characteristics of the structure. The results of this study showed that by increasing the height of the crown, the flow head and the weir angle relative to the flow horizon increase. The results also showed that the new relationship with R 2 = 0. 9984 has high accuracy for measuring critical depth and flow rate.

Crude oil is one of the most important sources of energy and its large scale production, transmission, consumption and disposal, making it one of the most important and common types of environmental pollution in the worldwide. In order to investigate the effects of phytoremediation and bioremediation on translocation of Total Petroleum Hydrocarbons (TPHs) in crude oil contaminated soil, a factorial experiment based on completely randomized design with three replications was conducted. Three rates of crude oil contamination; 0 (C0), 2 (C1) and 4% w/w (C2) and four remediation treatments; Lolium perenne (T1), Pseudomonas putida+Phanerochaete chrysosporium (T2), Lolium perenne+Pseudomonas putida+ Phanerochaete chrysosporium (T3) and control (T0) were applied. At the end of experiment, TPHs concentrations in different depths of soil column (5, 15, 25, 35 and 45 cm depths) were measured. The results showed that the different remediation treatments decreased the TPHs concentration in the root zone and T3 treatment decreased the concentration of TPHs both in C1 and C2 contamination rates by 34 and 59%, respectively. Oil compounds were also observed in the uncontaminated sub layers which indicated oil compounds transported from upper layer to lower layers. The lowest TPHs translocation to sub layers in the soil columns observed in T3 remediation treatment and the highest amount of TPHs translocation to sub layers observed in T2 remediation treatment. Generally, remediation treatments in oil contaminated soil degrade and decrease oil compounds especially in root zone but cannot prevent oil compounds movement and translocation to sub layers. Consequently, oil compounds may enter to groundwater.

This study applied the "Transboundary Waters Interaction Nexus (TWINs)" framework to the Hirmand/Helmand River hydropolitical interactions to figure out what can be learned by policy and decision makers by studying the past experiences about transforming conflicts and current ambitions. Analyzing coexisting conflict and cooperation in the Hirmand River by TWINs framework shows that from 1870 until 2020, in most periods, the Hirmand water conflicts have been politicized. But due to the westernization tendency and anti-Iranian sentiment procedure in Afghanistan during 2010-2020, water conflict has been increased and is opportunitized. As a matter of fact, the existence of a bad treaty over shared water, in addition to the international funds and supports from constructing dams in Afghanistan has been given the upper hand to Afghanistan in current negotiations over the Hirmand River Basin. The result of the TWINs framework and past experiences shows that bargaining purely over technical issues in the Hirmand River Basin cannot put water allocation in this basin in a peaceful situation. Therefore, the riparian states should rely on the interdependencies in social-economic, cultural, and security fields in order to create a sustainable and equitable relationship, which ultimately can create common values and norms in riparians’ water interactions. In other words, Iran and Afghanistan's water conflict needs outside the water box's solutions. This also highlights the importance of the depoliticization of Hirmand water interactions for preventing political frictions in hydropolitical relationships.