نشریه دانش آب و خاک
سال بیست و ششم شماره 4 (زمستان 1395)

The effect of dynamic vertical impinging jet on the static and dynamic scour depth is investigated in plunge pool bed, concerning the laboratory model. Experiments are conducted by changing jet installation height and a variety of grain size distribution. The basic scenarios are implemented with different nozzle elevation i.e. 24, 35.5, and 44 cm from the surface of alluvial bed. Then, the sub scenarios are developed by changing the grain size of alluvial bed with average diameters of 4.06, 7.14, and 8.73 mm and the output velocity of flow, with a variation range of 2.04 to 10.36 m s-1. Toward this end, concerning laboratory observations, various types of scour hole are classified based on the formation of the hole and the pressure factor of the jet. The results in adition to present an innovative classification of dynamic scour holes led to introduce an equation for estimating the relative difference of dynamic and static scour depths. A non-dimensional equation was presented as a simple and precise equation which would be recommended for estimation of the relative difference of dynamic and static scour depths (dd-ds)/hj. The relation had the correlation coefficient and root mean square error values of 0.72 and 0.096, respectively.

Hydraulic jump is a rapidly varied flow in open channels which performs an effective role in dissipation of the kinetic energy of flow at downstream of water structures. In the present study the characteristics of hydraulic jump, including sequent depth, energy dissipation, bed shear stress and velocity profiles at different sections, on rough bed with discontinuous roughness elements of lozenge shape have been investigated. The experiments were carried out for a range of Froude number values from 4.3 to 12.4 in three roughness densities and four combined arrangements of roughness elements. The results of this study showed that the velocity profiles on rough beds were similar but somehow different from those of wall jet on smooth bed. The dimensionless boundary layer thickness was 0.53 on rough bed that was more than corresponding value on smooth bed with the amount of 0.16. As the roughness density increased the bed shear stress produced by the interaction of upstream supercritical flow with the roughness elements enhanced so the energy loss increased and as a result the sequent depth decreased. In the arrangement of ternary combination of roughness elements with density of 10.67 % the maximum reduction value of the sequent depth was about 29.39%, the increase of the energy dissipation relative to hydraulic jump on smooth bed was10.94% and the bed shear stress coefficient on rough bed was about 13.54 times as much as its corresponding value on smooth bed.

Accessing to clean and high quality water sources has always been one of the main concerns of humanity. Therefore, determination of water quality is essential for various applications e.g. irrigation. In this study, irrigation water of Ajichai River in stations (Akhula, Arzanagh, Markid and Vaniar) is initially classified using USSL diagram. After that, feasibility of support vector classifier, K-nearest neighborhood and artificial neural network classification methods is assessed. Evaluation of data mining methods presents high accuracy and performance of these methods in assessment of water quality levels. In this study, the aforementioned methods are ranked by accuracy using kappa and error rate statistics. Careful examination of the results demonstrates that the support vector classifier which uses kernel functions is highly capable of solving various problems, and with an average ranking of 1.25 is the most efficient mining method followed by K- nearest neighborhood method with an average ranking of 1.75 and artificial neural network with an average rank of 2. These are also suitable methods for determining water quality classification.

Low application efficiency is the main problem of surface irrigation systems. In order to compare and improve furrow irrigation design methods including FAO, SCS, volume balance, kinematic wave and zero-inertia methods, field experiments were conducted for measuring design parameters of furrow irrigation. Results showed that the volume balance method gave the most accurate results of infiltration equation. Also attributing an intake family of the SCS method for field data caused error in the computation. Adjustment of SCS advance time equation and volume balance methods increased the model accuracy. With improvement ofSCS advance time, the residual mass coefficient (CRM) and root mean square error (RMSE) of advance time changed from -0.4 to -0.019 and from 10.36 to 2.34 min, respectively. Improving volume balance method, using surface and subsurface storages and modified Kostiakov-lewis infiltration equation, decreased the RMSE and CRM advance time from 8 to 6.26 min and from 0.32 to 0.25, respectively. Results showed that short time steps and more iteration should be performing for less error in the improved volume balance method. Created contours by WinSRFR4.1 model allow user to search a set of variables by consideration of hydraulic and practical conditions to achieve high level of uniformity and efficiency at zero-inertia and kinematic wave models.

Overuse of nitrogen fertilizer may result in nitrate accumulation in vegetables. The objective of this study was to determine the effect of Ammonium nitrate fertilizer and foliar application of mixed amino acids on the yield and nitrate accumulation in radish (Raphanus sativus). The experiment was based on the randomized complete blocks design and was carried out in pots filled with 6 kg of agricultural soil in factorial form with three replications. Three levels of nitrogen fertilizer (ammonium nitrate), N1: 0 mg, N2: 45 mg, N3:90 mg per one kg of soil and three levels of mixed amino acids (provided by Inagrosa company, Spain) A1: 0, A2: 1.5 and A3: 3 ml per one liter of water were used. Based on the results, the interaction effects of N fertilizer and amino acid application were significant on the yield and nitrate concentration. The results showed that the highest yield was in treatment N3A3 (2489 gr per pot) compared with the other treatments. Nitrate concentration in leaves and glands was increased with increasing the amount of ammonium nitrate. The highest concentration of nitrate in leaves was in treatment N3A1 (431 mg kg-1FW) and in glands was in treatment N3A2 (1331 mg kg-1FW). In leaves, foliar application of amino acid increased the total N and decreased the nitrate concentration. Foliar application of amino acids affected the nitrate reductase and glutamine synthetase and decreased the nitrate accumulation in leaves but had no effect on nitrate concentration of glands.

In order to evaluate the effect of phosphate fertilizers and organic compounds on some growth characteristics of the radish (Rhaphanus sativus L) irrigated with chromium- contaminated water at the concentration of 0.25 mg L-1, a greenhouse experiment was conducted at the Faculty of Agriculture, Shahrood University of Technology as a randomized complete block design with three replications. The treatments were: control, di-ammonium phosphate (41 mg P kg-1), triple superphosphate (41 mg P kg-1), alfalfa powder (1%), humic acid (1.38 mg kg-1), di-ammonium phosphate alfalfa powder, humic acid di-ammonium phosphate, triple super phosphate humic acid and triple superphosphate alfalfa powder. Analysis of variance revealed that there were significant differences among treatments on soluble phosphorus of soil, root chromium VI, electrical conductivity (EC) and pH. The most effective treatment for reducing chromium VI concentration of the radish root, was observed in application of triple super phosphate combined with humic acid, so that its concentration was reduced by 57.5 percent in comparison to the control treatment. The concentration of chromium VI in the root was 59.11 percent more than thet in the shoot. Considering the edible root of radish, it seems the use of phosphate fertilizers and organic compounds can decrease the absorption of chromium in the radish plant and prevent the accumulation of chromium VI in the tissues of the plant, especially in root.

Marls are the most susceptible geological formation of erosion and keeping a permanent crop cover on the soil of this formation is difficult due to some limitations such as the instability of soil
structure, poor soil productivity and low soil moisture storage. Polymers can be investigated as one of options to protect soil resources in these formations. This study was conducted to compare the effects of polyacrylamide (PAM) and polyvinyle acetate (PVAc) on improving soil properties and germination rate in the marl formations. PAM and PVAc were sprayed on the soil surface with 0.0, 33.3, 66.6, 100.0 kg ha-1 amounts in three splits. In total 32 boxes of polymerized soil were provided and wheat seeds were planted in them. The soil physical properties along with the wheat germination percentage were evaluated in the polymerized soils after five rainfall simulations (40 mm h-1 for 30 min). The experiment was conducted as factorial using a completely randomized design with three replications. With an increase in the two polymers rates, aggregate size, aggregate stability and saturated hydraulic conductivity were significantly improved whereas bulk density and soil surface resistance were strongly decreased in the prepared marl soil. Water holding capacity and available water of the soil decreased after the application of PAM while no significant differences were found after treating with the PVAc. This study revealed that the PVAc had the same role with the PAM in improvement of soil physical properties and in contrast it had no negative effect on the water holding capacity. Therefore, the PVAc can be successfully considered as a replacement for the PAM in the marl areas.

Potential evaporation is a component of the water cycle in nature and its prediction is a complicated and nonlinear practice. In this regard, the purpose of the present study was to provide the time-series prediction model of daily evaporation potential of Tabriz station using the two approaches of neural network and neural network- wavelet through de-noising. Daily time-series data of pan evaporation in Tabriz station consisted of 4309 days for the period of 1992-2011 were considered as the data base for running the above-mentioned models. Neural network prediction model was routed based on the three time series with 4, 7 and 10 days lag time of the normalized original signal. In the second approach, the main time series signal using Meyer wavelet was decomposed to 12 levels and the highest-frequency signal was removed as noise from the time series. Then, Neural network-wavelet model was implemented based on 36 time series with 4, 7 and 10 days delays. The evaluation of the results of these models by statistical and graphical criteria, indicated following A structure of 3-10-1 with correlation coefficient of 0.80 and mean square error of 0.125, and another structure of 36-8-1 with the correlation coefficient 0.917 and mean square error of 0.0858 were known as suitable structures in neural network and neural network-wavelet approaches, respectively.

The reviews of past researches have shown that abutment scour plays an important role in bridge failures. Hence, protection of bridges against scour is a significant issue. For existing bridges, armoring methods, like riprap, has a wide application. In areas where providing stones is expensive concrete blocks or similar techniques have been applied. In this study for the first time the application of six-legged concrete elements has been experimentally investigated. The six-legged elements have been placed in three different densities (open, medium and dense) and three different placement depths (under the bed, above the bed and medium case). Each alternative has been tested under different flow conditions. Generally, the results proved that the six-legged elements could considerably reduce the scour depth under different flow conditions so as the maximum scour depth of abutment nose was reduced up to 86%. The maximum reduction of scour depth was obtained when the high dense six-legged elements had been placed above the bed.

In this study, performances of the hydrological model of Soil and Water Assessment Tool (SWAT) and support vector machine (SVM) in monthly simulating the runoff of Lighvanchai river were evaluated. After collecting the required data, the models were calibrated and verified. The SUFI-2 algorithm was used for uncertainty analysis of the SWAT model. The discharge of the Urmia lake basin was simulated using SWAT model and the results obtained for the Lighvan station were used in this study. The SVM model was applied using the rainfall and runoff data measured in the Lighvan station. In order to improve the results, the time series with different lag times were used. Three statistical criteria including coefficient of determination (R2), Nash-Sutcliffe coefficient (NS) and root mean square error (RMSE) were used to evaluate the performances of the models. The results revealed the ability of the both models in simulating the discharge of Lighvanchai river. However, the SWAT model had better performance than SVM in simulating the maximum values of the runoff of Lighvanchai river with NS and RMSE values of 0.71 and 0.41 m3s-1 respectively.

The large numbers of environmental management decisions associated with soil are influenced by its evolution because soil is a dynamic environment. Based on necessity of soil genesis and evolution assessments, this research work was carried out along an altitudinal transects of Kaleybar Chai Sofla sub-basin in Arasbaran forests and completed by soil morphological and micromorphological studies, physical and chemical analyses, soil classification and calculation of Harden index in eight control profiles. Results revealed the presence of four soil orders of Entisols, Inceptisols, Mollisols and Alfisols in two replications with different families in two elevation parts along altitudinal transects, due to various soil forming processes such as weathering, littering and humification, calcification and lessivage. Observation of weathering rate increasing, soil profile thickness development, differences in variety and intensity of pedofeatures such as clay coating, calcitic pedofeatures, organic residues, excrements and derived micromorphological properties by decreasing of elevation and also calculation of Harden index revealed the presence of more developed Entisols, Inceptisols, Mollisols in lower elevation in comparison to the same orders in the upper one. But the inverse condition of Alfisols evolution was related to the role of vegetation in soil stabilization, development and evolution in unsuitable topographic condition of upper parts of the study area. Therefore, it seems that elevation is not the main soil forming factor in the studied scale, but it can be identified as a main effective factor in soil evolution. Besides main findings, results showed that different horizon distinction revealed different concepts from soil evolution.

In order to study the effects of vermicompost and chemical fertilizers on soil physicochemical characteristics and wheat (Triticum aestivum L. cv. Bahar) yield, a field experiment based on randomized complete block design (RCBD) with 11 treatments and 4 replications was conducted in Mahidasht Agricultural Research Station during growing season of 2013. Treatments included, T1: application of 50% NPK chemical fertilizer, T2: application of 50% NPK plus 3 tons ha-1 of vermicompost, T3: application of 50% NPK plus 5 tons ha-1 of vermicompost, T4: application of 50% NPK plus 7 tons ha-1 of vermicompost, T5: application of 100% NPK, T6: application of 3 tons ha-1 vermicompost, T7: application of 5 tons ha-1 vermicompost, T8: application of 7 tons ha-1 vermicompost, T9: application of 3 tons ha-1 vermicompost plus crop fertilizer requirement minus equivalent amount of chemical fertilizers in 3 tons vermicompost, T10: application of 5 tons ha-1 vermicompost plus crop fertilizer requirement minus equivalent amount of chemical fertilizers in 5 tons vermicompost, T11: application of 7 tons ha-1 vermicompost plus crop fertilizer requirement minus equivalent amount of chemical fertilizers in 7 tons vermicompost. The lowest value of pH (7.7) was achieved by application of 7 tons vermicompost (T8) which decreased 5.39% compared to chemical fertilizer treatments. Also, the lowest bulk density (1.25 g cm-3), the greatest organic carbon percent (1.84) and the highest total porosity (57.16%) belonged to the application of 7 tons ha-1 vermicompost. Soil total nitrogen by application of 7 tons vermicompost was 80.45 and 72.52 percent higher than 50% and 100% NPK treatments, respectively. Results showed that application of 7 tons ha-1 vermicompost (T8) followed by T11 and T4 treatments showed the highest effect on soil physicochemical properties compared to other treatments especially chemical treatments. Also, the highest wheat yield was achieved by application of 7 tons ha-1 vermicompost plus crop fertilizer requirement minus equivalent amount of chemical fertilizers in 7 tons vermicompost (T11) and followed by application of 5 tons ha-1 vermicompost plus crop fertilizer requirement minus equivalent amount of chemical fertilizers in 5 tons vermicompost (T10).

Kinetic energy of the water over large spillways should be dissipated in the stilling basins by generation of a hydraulic jump in order to prevent scouring of riverbed and damaging the downstream structures. There are many types of stilling basins, and the most popular ones in practice are the standard USBR basins. The purpose of this study is to evaluate the behavior of perforated and continuous sills in stilling basin as well as their effects on the characteristics of a hydraulic jump including jump length and relative dissipated energy. Results of experiments indicate that the perforated sill, in comparison with the continuous one, has a better behavior in controlling and stabilization of hydraulic jump within the stilling basin which increases the energy dissipation and reduces the jump length. Furthermore, the results show that the perforated sill with 50% opening reduces the basin length about 61% of the required basin length for a free hydraulic jump. Moreover, perforated sill basins are able to dissipate 60% of the inflow energy at Froude number 4.5, while dissipation of energy increases to 90% at Froude number 12.

The van Genuchten (vG) function is often used to describe the soil water retention curve (SWRC) of unsaturated soils. The objective of this study was to evaluate a method to determine the vG model parameters m and α of 100 soil samples of Guilan province from the fractal dimension of SWRC. Also, we used two models introduced by Lenhard et al and vG for estimating m from pore size distribution index of Brooks and Corey (BC) model. In both of the mentioned methods, the relationship between pore size distribution index of BC and SWRC fractal dimension was used. Also, vG parameters using Rosetta software were estimated and then, the amounts of vG parameters from the Rosetta, fractal method and RETC were compared. Results showed that Rosetta software had a better estimation of vG parameters than the Rosetta. The estimated vG model parameters m and α obtained with the above-mentioned different methods, in conjunction with measured saturated water contents, were used to estimate water contents at different matric potentials and compared with determined values by RETC via fitting of vG model on the measured values. The estimated SWRC data via fractal method were compared with those obtained with the Rosetta model. Results showed that fractal method had more accurate performance for prediction of SWRC than the Rosetta. Even though, the Rosetta software could lead to better estimates of the vG model parameters than the fractal approach, it was not capable of predicting SWRC as accurately as the fractal approach. This is due to the fact that estimation of the water content is a result of an interaction between the estimated vG model parameters, α and m.

Discharge measurement by sluice gates is one of the classical issues in hydraulic engineering. Based on the energy conservation relation, this study presents a novel method for estimating the discharge coefficient of sluice gates under free and submerged flow conditions. This method gives the discharge coefficient of sluice gates only as a function of upstream depth and bottom pressure measured by manometers located under the gate lip and is independent of flow conditions (free and submerged), gate opening and tailwater depth. For evaluating the applicability of the proposed equation in this research for estimating the flow discharge, the experimental results (418 runs) of two sluice gates with 25 and 40 cm widths are used in the conditions of presence and absence of end baffle blocks for both free and submerged flows. Independency of discharge coefficient from the tailwater depth has important advantages such as: continuous estimation of discharge coefficient under free and submerged flow conditions using a unified equation and higher accuracy at the lower submergence. Also being independent of tailwater depth makes easy flow estimation even at the presence of baffle blocks on the stilling basins. The results show that, applying the energy loss coefficient in the proposed equation decreases the mean absolute relative errors to 0.4% and 2.6% for free and submerged flow conditions respectively. Also the proposed equation has a relative error less than 5% under submerged flow conditions. The proposed method is very sensitive to bottom pressure head especially under higher submergence levels.

Soil pollution because of heavy metals not only can directly affect the soil physical and chemical properties but also may turn out to be a serious hazard to human health due to affecting both the food chain and groundwater. Zanjan Province in Iran is considered as one of the most industrialized areas in country due to its heavy metal mining industries. The main purpose of the present study was to evaluate the spatial distribution of heavy metal concentrations using geostatistics approach and to provide the detailed soil maps in order to identify the contaminated farmlands affected greatly by Zanjan contaminated industrial site. Hence, 150 topsoil (0-10 cm) samples were randomly gathered from the area surrounding the contaminated industrial sites to adjacent farmlands with 20,000 ha area in order to assess the spatial variation of heavy metals such as zinc, copper, lead and cadmium. Total zinc, copper, lead and cadmium after the digestion process were measured using atomic absorption spectroscopy (AAS). Therefore, soil enrichment factor (EF) was calculated to identify heavy-metal affected sites. The results of kriging interpolation analysis showed that heavy metals concentrations in the eastern and central parts of the Zanjan area generally exceeded the threshold values (Pb=402.5 mg/kg, Zn=670 mg/kg, Cu=585 mg/kg and Cd=10.5 mg/kg). Therefore, the eastern and central parts of the study area seem to have a high priority for the both soil leaching and phytoremediation operations.

To investigate the interaction effect of Cd and Zn on growth and chemical composition of canola, a factorial greenhouse experiment in a randomized complete block design with two factors including Cd at eight levels (0, 5.0, 5.2, 5, 10, 20, 40 and 80 mg kg-1 soil) and Zn at eight levels (0, 5, 25, 50, 100, 200, 400 and 800 mg kg-1 soil) with three replications was conducted in a loamy sand soil. After 60 days, the dry weights and concentrations of Cd, Zn, Fe, Mn and Cu in shoots and roots were determined. At levels of 2.5 and 0.5 mg Cd per kg of soil, all levels of Zn increased shoot and root dry weights. At higher levels of Cd, applications of 5 and 25 mg Zn per kg of soil increased the shoot and root dry weights, but at higher levels of Zn, a decrease in these parts was observed. Moreover, at levels up to 5 mg Cd kg-1, application of Zn even at level of 25 mg Zn kg-1decreased Cd concentration in shoots in comparison with control. However, at higher levels of Cd, this decrease was achieved only at 5 mg Zn kg-1. Increasing the level of Cd at any level of Zn decreased the Zn concentration in shoots. Application of Zn at each level of Cd, first increased and then decreased the concentration of iron in shoots and roots. Zn supplementation at each level of Cd increased concentration of Mn in shoots and decreased its concentration in roots. In addition, Zn application at each level of Cd decreased the concentration of Cu in both shoots and roots.

Weir and gate have many applications in irrigation networks because of their simple and accurate equations for flow measurement and their ability in water level controlling. Water flow in river and canal pathes always contains suspended sediment particles and floating materials. In this condition, weir and gate can be combined together and create an integrated system entitled weir-gate that can convey sediment particles under the gate and floating materials over the weir. In this research, discharge coefficient of prismatic weir-gate was studied under free flow condition with different gate openings and flow discharges. Variation of discharge coefficient of prismatic weir-gate was investigated in different angles of prism surfaces including 60˚ vs. 60˚ (symmetrical prismatic), 45˚ vs. 47˚ (upper prismatic) and 75˚ vs. 45˚ (lower prismatic). Results showed that discharge coefficient increased by increasing, and parameters. Comparing the results of different angles of prisms showed that the lower prismatic weir-gate had the highest discharge coefficient among the models in different hydraulic conditions. Discharge coefficient of the symmetrical prismatic weir-gate was higher than the upper prismatic model. This could be resulted from the extreme contraction of flow passing under the gate and increasing the local losses. Linear equations were proposed with acceptable accuracy for the weir-gates. Comparison of the results with the reported results by other researchers showed that the discharge coefficient of prismatic weir-gate was higher than the other kinds of weir-gates within the tested condition.

Many factors are participated in the snowmelt process, therefore accurate estimation of it is one of the major challenges in water resources management. Snowmelt runoff prediction provides the necessary tools for effective and efficient management of water resources, including reservoir management, groundwater management and flood warning. In most cases there are little earth-observing information for snow properties which is one of the limitations of snowmelt flow modeling. For this purpose, the modified Penman-Monteith equation using climate data from Lighvan weather station in the East Azarbaijan Province was applied in order to estimate runoff from snowmelt. Two-thirds of data were used for training and the rest one-third for verification of the model. Finally, the modified Penman-Monteith equation with mean correlation coefficients values of 0.89 and 0.85 for training and verification stages, mean average absolute error values of 0.57 and 0.37 m3s1 for training and testing stages, was presented as an appropriate model to estimate the snowmelt flow based on climatic parameters.

The aim of this research was comparison of the interactions of Eisenia fetida earthworm and organic matters on some hydraulic properties of two fine and coarse-textured soils under two compaction levels. A factorial experiment was conducted as the completely randomized design with 24 treatments and three replications under growth room conditions during six months. The factors were two soil textural classes (sandy loam and clay loam), three organic matter levels (0, 20 g kg-1 of both wheat straw and cow manure), and two compaction levels (1.3 and 1.45 g cm-3) with or without earthworm. The results showed that the both used organic matters averagely increased the soil field capacity (4.1%), permanent wilting point (2.4%) and available (8.78%) moistures values, meso騧pores volume (4.3%), while decreased the macropores volume (11.75%) in the both textural classes. Also, the highest available water content was observed in straw and clay loam soil treatments. Soil compaction decreased the soil saturated moisture value (11.6%) and macropores volume (29.5%) and increased meso騧pores volume (12%), while earthworm increased the mean of saturated moisture value (8.1%) and macropores volume (17%) and decreased meso騧pores volume (5%), averagely. The results of this study indicate that inoculating soil with earthworm can improve hydraulic quality of fine and coarse-textured soils under compaction condition even with using minimum organic matter.

Today, because of consecutive droughts and population increase, management and optimum use of water resources play an important role in sustainable development. One of the methods in water resources management is to use underground dams. Underground dams cause to reinforce aquifer water storage and consequently, this reinforcement leads to better performance of Qanat. In the present study, the changes of the located ground water table below the bed of Soofi river (located in Soofi village in west Azerbaijan) were studied using water table data of three observed wells, two drainage systems (QANAT) and MODFLOW software. After calibration of the model and modeling with underground dam construction, water level in observed wells was predicted. Then, the effect of underground dam construction on Qanats and water balance was investigated. The results showed that the obtained data from modeling had acceptable accordance with observed data in a year after the construction of underground dam. Also, the comparison of the observed and predicted data in two upstream wells showed that, the difference between the two the observed wells was limited to a few centimeters and the percentage mean square error was 4.34 and 7.37 for steady and unsteady conditions, respectively.

Optimized water allocation may be considered as a valuable solution to increase the productivity of water resources in arid and semi-arid areas. To achieve this purpose, the main resources of water consumption in Baghmalek plain (Khuzestan province) for duration of October 2013 to September 2014 and also water table heights for nine years (2002 to 2011) were evaluated. In this study, the final model was developed by combining the two cropping pattern multiobjective optimization and groundwater simulation models. Also, groundwater flow was simulated for addressing optimal discharge scenarios based on finite difference numerical approach using Modflow software. Study years were divided into 36 seasonal stress periods and hydraulic conductivity, specific yield and recharge were calibrated in these periods. The results showed that the flow model had an acceptable simulation accuracy by variance error of 3.05 and 3.92 in calibration and verification processes, respectively. Furthermore, the prediction of water table after the optimal discharge scenario indicated that the May and June months were the main periods of groundwater management.