نشریه دانش آب و خاک
سال بیست و نهم شماره 1 (بهار 1398)

The main purpose of this paper was to develop optimal models of reservoir operation in order to supply different downstream demands based on fuzzy logic and meta- heuristic algorithms. In this regard, firstly, the optimal values of the released water releases from Zayanderood reservoir during the operation period based on the objective functions and different constraints, were extracted using meta- heuristic algorithms including Genetic Algorithms, Particle Swarm Optimization, Differencial Evolution, Harmony Search and Charged System Search, considering the inflow and the downstream demands during this period. Then, with regard to the optimal values of the released water over a long period, using fuzzy logic based models such as ANFIS and a new combination of ANFIS and meta-heuristic algorithms, various types of operation models were developed. Finally, the performance of these models were evaluated with various performance evaluation criteria such as reliability, reversibility, vulnerability and sustainability.The results showed the proper performance of the new hybrid system in developing the reservoir operation model. According to the results, the sustainability values achieved by the new hybrid and classic systems were 0.30 and 0.18, respectively. Also, this hybrid system showed a good performance by supplying 95.99% of the total demands of Zayanderood reservoir system.

Compact clay layers are the most impermeable layers in earth dams. One of the most important factors in the failure of earth dams is the piping that the existence of cracks in the dam core is one of the major reasons for the formation of this phenomenon. Due to the nature of clay and its unique geotechnical properties, these layers are damaged over time by cracking. The cracks healing property in clays closes its external cracks. Self-healing of clays has been considered by researchers as one of the positive characteristics of clays. In this research, a new method is presented to assess the self-healing of clays using pinhole test. In order to reach the appropriate range of plasticity index (7<PI<26), three soil samples are prepared from the Vanyar dam borrow pit as follows: first sample with 10% bentonite, second sample with 20% bentonite and third one just natural soil. The results showed that by adding bentonite, for optimum moisture content and 2% below, soil dispersion reduced and the soil became non-dispersive. Moreover, self-healing phenomenon was visible and predictable with increasing of bentonite in the natural soil. This phenomenon was observed for 20% bentonite having high plasticity index and swelling from early age. The sample with 20% bentonite and moisture content 2% lower than optimum showed the most reduction in outflow (38%) compared to the natural soil sample. Thus, plasticity index increment in the suitable range could cause the non-dispersivity of clay and increasing of self-healing ability.

Tillage operations in swelling soils comprise some difficulties due to the fact that they are sticky during wet periods and hard in dry conditions. Applying soil conditioners is one of the solutions for managing these soils. In this study, a completely randomized (CRD) factorial experiment with two factors including type (Arabic gum and Chitosan) and amounts (zero, 5, and 10 grams per kilogram) of two soil conditioners with three replications was carried out to investigate the effect of these natural biopolymers on the improvement of the physical quality of these soils. Several soil characteristics were examined after three weeks of incubation time. The results showed that the use of Arabic gum and Chitosan increased saturated hydraulic conductivity (Ks) (approximately twice) and wet-aggregate stability (WAS) (approximately 3-4 times). The mean weight dimeter (MWD) index increased around twice as a result of the treatment of soil by Arabic gum and decreased around half due to soil treatment by Chitosan. Regarding soil water storage, Arabic gum retained more water in soil exposing to evaporation force. The swelling volume of the examined soils decreased around half as a result of the application of both above-mentioned biopolymers. Therefore, the above-mentioned biopolymers can be used to treat swelling soils hoping a considerable reduction in their swelling and shrinkage characteristics.

Bacteria with high phosphate solubilization ability and resistant to high temperatures are good candidates for using in phosphatic microbial fertilizers (PMF). Accordingly, in this study the dissolution of phosphate, thermal tolerance and viability of seven PSB (Pantoea agglomerans P5, Pseudomonas fluorescens Tabriz, P. putida Tabriz, Pseudomonas sp. C16-2O, Enterobacter sp. S16-3, Bacillus megaterium JK6 and B. firmus) were evaluated in the basal formulation of rock phosphate (45 g), bagasse (30 g) and sulfur (15 g) after providing appropriate initial microbial population. The prepared PMFs was divided into two parts and the number of viable cells was obtained after three and six months by plate count method. The provided PMFs were subjected to microbial counts in two ways. A) Half of fertilizer samples, were stored at room temperature then viable cells counted and B) The other half of PMF were counted after they had been exposed to a temperature of 55 °C for 16 hours. The results showed that there was a significant difference between different phosphorus sources in terms of phosphate dissolution, and dissolution of bacteria from TCP sources compared to rock phosphate was two-fold. The highest and lowest dissolution of phosphate observed in the bacterium P. agglomerans (562 mg/l) and B. firmus (395 mg/l), respectively. None of the bacteria in PMFs formulations did not tolerate at temperatures up to 55°C, but PMFs that stored at room temperature, after three and six months of production, had an average population of 4.3 × 105, and 0.4 × 104 CFU/g, respectively.

Among the issues related to bridges distraction, a flood which causes scouring has been known as the main reason of bridges destruction. Therefore, finding an effective solution is vital for decreasing scouring depth. In this study, the effects of local roughness elements with different distance were investigated for a semicircular abutment under clear water scouring condition. Results showed that existence of roughness reduced the scouring process and reduced the final scour depth by 47%. There was a significant relationship between roughnesses function and the distance between them. So that the existence of an optimal value for the distance between the roughnesses increased the roughness function and decreased the scouring process. In addition, the study of vertical velocity profiles revealed that existence of positive vertical velocity in the hole located at upstream of the abutment and also negative velocities at higher depths were the indicator of downflows. As a result, these downflows lead to the formation of powerful vortexes inside the scouring hole and in front of the abutment. Comparison of the flow profile around the roughened abutment with the control abutment showed that velocity of downflow is significantly reduced for abutment with roughness. Moreover, the depth of scouring hole was reduced at behind of the abutment, due to the impact of roughness on vertical velocity profiles at downstream of abutment. So that, the velocity reduction of the vertical flow in the front and behind of the roughened abutment was to 0.13 U and 0.4 U (U approaching flow velocity), respectively.

The best way to prevent the pollution of ground water is identifying the pollution sources and vulnerable areas then providing a suitable management practice. The aim of this study was to determine the vulnerability map for urban areas and paddy fields of Babol city to present the management options. For these purposes, the aquifer of the city was evaluated with DRASTIC model. The required parameters were provided for the hydrological system and then for considering the effects of urban areas and paddy fields, some parameters' weights and rankings in DRASTIC model were modified based on the prevailing conditions in the study area. Considering the main characteristics of the study area (urban and paddy fields) DRASTIC index was calculated and the aquifer vulnerability of Babol city that was in which showed of 127 to 174. The presence of the paddy fields which showed around the city as well as unconfined aquifer in paddy fields' domain have increased the vulnerability of the aquifer in the peripheral areas of the city. Urban, multiple urban wastewater wells and absence of a centralized sewage collection system, have provided the conditions for leakage of the pollutants into the aquifer and this has caused the urban area to be considered as a region with moderate vulnerability. It is recommended to prevent to prevent from continuing damage to the Babol aquifer by employing some management practices such as centralized sewage collection system and reducing the use of agricultural inputs in paddy fields.

In this research, the discharge coefficient values of side orifices are modeled using ANFIS and the ANFIS-GA methods. To simulate the discharge coefficient, the effects of the ratio of the main channel width to the side orifice length (B/L), the ratio of the side orifice height to its length (W/L), the ratio of the flow depth in the main channel to the side orifice length (Ym/L) and the Froude number (Fr) were considered. Eleven different models were introduced for each of the ANFIS and ANFIS-GA models to estimate the discharge coefficient. Next, in order to compare the soft computing models’ results with the results of the computational fluid dynamics (CFD), the side orifice discharge coefficient was simulated using FLOW-3D model. To model the flow field turbulence, the standard k-ε and RNG k-ε turbulence models were used. According to the CFD model results, the RNG k-ε turbulence model simulated the flow field turbulence with higher accuracy as compared to k-ε model. Also, the MAPE and RMSE values for the estimated discharges by the CFD model were equal to 12.204 and 0.001, respectively. By analyzing the results of the ANFIS, ANFIS-GA and CFD models, the ANFIS-GA model was introduced as the premier model.

In this research, gradual and rapid changes of hydro-climatological variables, trends were analyzed for the Lighvanchai basin. Also, the natural (stationary) and impacted periods were identified. For this purpose, the traditional Mann-Kendall (MK1), modified (MK3) and Pettitt methods were used and for determination of the trend line slope the Senʼs estimator was used. Results showed that streamflow values of Lighvanchai River (in Hervy station) had a downward trend in the all time scales. In the spring, all precipitation related variables showed a decreasing trend. In the case of temperature variables, there was an increasing trend at the most of the studied time scales, which were significant from January to  May. Furthermore, the differences between Tmax and Tmin showed an increasing trend. On the other hand, air relative humidity time series showed a decreasing trend (specially in winter). It could be concluded that the combination of these changes led to decreasing trend in basin runoff. The result of Pettitt test showed that  the streamflow of  Lighvanchai (in Hervy) had a sudden change point, so that the average discharge in the recent period had been decreased about 35% compared to the first period. Most of studied climatic variables such as air temperature and RH, had a sudden change point that the date changes of these variables and the basin discharges (at Hervy station) were occurred in the mid-1990s. Regarding the discharges of Lighvan station (upstream of basin) the null hypothesis of abrupt change point were rejected. Therefore, along with the effects of climatic factors the effectiveness of the human factors on reducing the runoff in the basin outlet at Hervy station was confirmed.

The grain size distribution of the riverbed materials plays an important role in the erosion, sedimentation, change of river morphology and riverbank stability. The complex hydraulic flow on the one hand and the changes in the composition of the sediment of the riverbed as the eroded or deposited particles on the other hand causes changes in the sedimentation and erosion patterns at the river confluences. The literature review shows that few experimental studies have been conducted on this topic. Although applying numerical models are entwined with some limitations, they could be used as the suitable and economical tools. In the present study, firstly the SSIIM1 model was calibrated by the measured data at the confluence of the two rectangular open channels with the crossing angle of 60o and then, the impact of riverbed materials’ grain size distribution on sedimentation and erosion patterns was studied. In this regard, four types of grain size distribution with the same D50 and different standard deviation (σg) values were applied and their results were compared with each other and with uniform distribution, as well. The results illustrated that the maximum depth of erosion was decreased by increasing σg and its spatial location was closer to the downstream corner of channel confluences. Moreover, the maximum height of the sedimentation increased with increasing σg. In the following, the spanwise changes in sediment concentrations and paths of maximum sediment transport have been detected.

This research was carried out to consider the effects of recreational human trampling on some soil physical and hydraulic properties in Fandoghloo Forest Park of Ardabil. A completely randomized design was conducted with three treatments of no trampling, moderate trampling and intensive trampling at five replicates.Water infiltration into soil under unsaturated condition was measured at the matric suctions (h) of 2, 5, 10 and 15 cm using tension infiltrometer. The infiltration data was modeled using Wooding method and then saturated hydraulic conductivity (Ks) and macroscopic capillary length (λc) using Gardner equation were calculated. The results showed that although trampling levels could not significantly affect the unsaturated hydraulic conductivity and soil sorptivitiy at different levels h, Ks and λc,but intensive recreational human trampling significantly decreased organic carbon (68.62%), total porosity (25.42%), field capacity moisture (46.81%), permanent wilting point moisture (51.72%) and final infiltration rate at h=15 cm (50%) and increased bulk density (46.07%) and soil penetration resistance (75.57%) in relation to the no trampling treatment; as a result, intensive recreational human trampling reduced physical and hydraulic quality of the forest soil.

The present study aimed to calculate the land versatility (overall land suitability) for irrigated wheat, alfalfa and potato in two adjacent areas in Zanjan plain using the combination of individual qualitative suitability degrees. Therefore in two adjacent areas located in Zanjan plain (in the east and west of Zanjan Zinc Town), with the total area of 4500 and 5500 hectares, respectively, 56 and 68 soil samples with distance of 1000 m were collected. After land suitability degrees determination for irrigated wheat, alfalfa, and potato based on the climatic data and soil and landscape analyses, continuous qualitative land suitability maps were produced using ordinary kriging estimator. Finally, the land versatility (overall land suitability) index, as an average of individual land suitability degrees for different crops, was calculated and then interpolated and mapped. The results showed that the soil pH for potato and the percentage of coarse fragments in the soil for all of the three studied crops caused some limitations. Comparison of land suitability maps revealed higher suitability of wheat and alfalfa farming in the eastern part of Zanjan Zinc Town in comparison with western part of it, while the suitability class for potato was marginal. Comparison of overall land suitability (versatility) index revealed a relatively high spatial variability in both of studied areas and also proved that overall suitability of the lands located in the east is more than the lands located in the west of Zanjan Zinc Town.

In recent years, declining the water level of Lake Urmia has caused water and environmental crisis in the area. Therefore, it is urgent to carry out an accurate and reliable management and planning which requires modeling the lake's water level for the future. In this research, the artificial neural network (ANN), adaptive neuro fuzzy inference system (ANFIS) and support vector machine (SVM) models were used to forecast the Lake Urmia water level fluctuations for one, two and three months ahead forecast horizons and finally, a supervised committee machine artificial intelligence (SCMAI) model was used to obtain a better performance than the used individual models. To develop the models, the current month [h (t)] and eleven months water level lags [h (t-1),…, h (t-11)] were introduced as input variables to forecast one, two and three steps ahead water levels. The datasets were divided into two subsets of training/validation (90%) and testing (10%). The performances of the models were evaluated based on the coefficient of determination (R2), the root mean square error (RMSE) and the mean absolute error (MAE). The results showed that the SVM models had better performance than the ANN and ANFIS models. The SCMAI model was applied to combine the used models’ outputs and illustrated that the SCMAI models are able to improve the performance of the individual artificial intelligence models. The results of the performance criteria for SCMAI model indicated that the one month step ahead water level modeling with R2, RMSE and MAE equal to 0.9896, 0.0547 m and 0.0421 m, respectively outperformed in comparison with SVM model which this performance is reliable for the two and three months step ahead lake's water level.

Due to limitations in water resources scarcity, application of pressurized irrigation methods is inevitable for optimum use of water. This study was conducted in Behbahan Agricultural Research Station, during three cropping seasons (2013-2016). The statistical design was split plot with the design of randomized complete blocks  at three replications. The main plots were crop requirements at levels 75%  (SDI75), 100% (SDI100) and 125% (SDI125) of full irrigation for subsurface drip and 100 (SD100)  of full irrigation for surface drip irrigation and sub-plots were Kabkab and Zahedi date palm varieties. Results of combined variance analysis showed significant difference between the irrigation levels (1%) based on water use efficiency. According to the comparison of mean values, the highest yield with 8490.9 kg/ha belonged to SD100. Zahedi variety showed the highest water use efficiency of 0.686 kg/m3 under SDI75. Comparison of mean interactions showed that Zahedi variety had the highest water use efficiency with the amount of 0.744 kg/m3 compared to others treatments. SDI75 caused 2509.6, 5019.2 and 2630.3 m3/ha water saving in comparison to SDI100, SDI125 and SD100 Respectively. Combined analysis of variance showed that irrigation levels and cultivars had a significant effect on fruit moisture at 1% and 5% level, respectively, but the interaction effects were not significant. Comparison of mean values showed that SDI75 was superior and ranked first in the stiffness of tissue with 10.4 Newton/m2.

In order to precise design, the determination of flow behavior in open channels have always been subjected by the hydraulic researchers. The traditional Manning-Strickler, Keulegan, and Colebrook-White equations provide inaccurate estimations for resistance coefficients in roughened rectangular channels. In this research, flow resistance coefficients both in smooth and rough rectangular channel sections were investigated by using experimental models and three types of river materials. The results show that the revised Strickler formula estimates Manning's n with an average error about 2.56%; and the revised Keulegan equation for smooth and Colebrook-White equation for roughened channels give some good agreements with the experimental measurements by an error of less than 4.91% and a correlation coefficient of 0.983. Some empirical derived equations are also presented which gives the value of Nikuradse sand equivalent roughness, ks, as a function of roughness diameter size. A new explicit formula presented for friction factor, f, using gene expression programming (GEP) for uniformly roughened rectangular channels with an average relative error 5.1% and the corresponding correlation coefficient, 0.981.

The root endophyte Piriformospora indica is plant growth promoting and induces tolerance to biotic and abiotic stresses in plants. To assess the effect of P. indicainoculation onMedicago sativaL. plantsunder water deficit stress, a trial was conducted in a factorial experiment based on completely randomized design with combination of two factors, soil moisture levels (100% AW (Available Water) and 30% AW) and fungi (inoculated with P. indica and non-inoculated) in three replications. The M. sativa seedlings (inoculated or non-inoculated ) were exposed to water deficit stress for the 45 days. The plant shoot and root biomass were increased by fungal inoculation that indicated growth promoting effect of P. indica. A significant decrease in plant biomass, leaf relative water content and mineral content were observed under water deficit stress. In this study fungal inoculation caused a significant increase in P, Zn, proline and protein contents in shoot and root, root phenol and Fe contents as well as chlorophyll and carotenoid contents at 30% AW in comparison with those in non-inoculated plants. Also, malondialdehyde in inoculated plants was lower than that in non-inoculated plants under both moisture levels. Generally, our results showed that the P. indica inoculation counteracted water deficit stress conditions in M. sativa and it could be proposed as a useful tool for alleviating the adverse effects of water deficit stress in host plant.