Evaluation of the effect of scenarios in the 6th report of IPCC on the prediction groundwater level using the non-linear model of the input-output time series.

Due to the increase in greenhouse gases, water and climate crises, increasing population, and decreasing water resources, accurately predicting the changes in the GWL is essential for the management of water resources. For this purpose, in this research, the MIROCES2L model was used to predict the climatic parameters of Birjand Plain under three scenarios of the sixth climate change report: SSP1-2.6, SSP2-4.5, and SSP5-8.5. The minimum temperature, maximum temperature, and precipitation parameters from these three scenarios were measured using the CMhyd model. The results indicated that the minimum and maximum temperature would generally increase in the future under the influence of climate change, but precipitation has a sinusoidal behavior and has a decreasing trend in the summer and spring seasons and an increasing trend in the winter and autumn seasons. Then, three ANN, NIO, and MLR models were employed to simulate groundwater depletion. The results indicated that the evaluation of the performance criteria of the NIO model is superior to the other two models, and it was chosen as the model for predicting groundwater depletion in the future period under the influence of climate change based on all three mentioned scenarios. The final results of this research indicated that the GWL of Birjand Plain in the future period (2024-2041) under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios would respectively decrease to 5.58m, 5.13m, and 5.38. The results of this research indicate that the need for sustainable management to conserve groundwater resources is also very important in the study area.

Field study of irrigation strategies with treated wastewater and saline water on heavy metal accumulation in barley grain.

This study examines the effects of three irrigation regimes with a combination of saline water and treated wastewater on the accumulation of heavy metals in barley grains. A field experiment was designed as a split-split plot arrangement in a randomized complete block design, in which treatments were different irrigation regimes (50%, 70%, and 100% full irrigation) and irrigation water types (saline water [SW], treated wastewater [TW], mixed water resources [MWR], and alternative irrigation [AI]). After cultivation and harvesting of the barley crop, the grain yield, 1000-grain weight, and contents of heavy metals in the grains were measured. The grain yield was enhanced by TW alone, MWR, and AI to 12.8%, 5%, and 9.5% under 70%-deficit irrigation; and 58.3%, 21.7%, and 8.7% under full irrigation, respectively. Based on the guidelines for safe limits of heavy metals in edible plants and livestock feed, the barley grains were safe for livestock and toxic for humans. The trend of heavy metal contents in the grains was Fe > Zn > Pb > Cu ≥ Cr > Cd. Irrigation with SW compared with TW increased Fe, Cu, Zn, Pb, Cd, and Cr contents in the grains to 11.75%, 10.97%, 5.22%, 19.15%, 3.45%, and 9.21%, respectively. The amounts of toxic elements of Cd and Pb were maximized by using MWR, whereas the Cr content in the grain was maximized by using AI. There were no significant difference in the metal uptake by the grains among all irrigation regimes in any irrigation water resource. However, compared with the other irrigation regimes, the full irrigation resulted in lower Zn, Cu, and Cd contents, whereas the 50%-deficit irrigation led to lower Pb and Cr contents in the grains. Therefore, irrigation with TW is recommended based on the grain yield, whereas AI is suggested due to lower Cu, Pb, and Cd contents in the grain, and MWR is recommended due to lower Cr content. Furthermore, full and 50%-deficit irrigation regimes are recommended to, respectively, maximize grain yield and minimize the toxic metal contents in the grain. PRACTITIONER POINTS: Mixed saline water and treated wastewater and alternative irrigation enhanced grain yield. Saline water versus treated wastewater increased the grain heavy metal contents. Alternative irrigation decreased Fe, Cu, Pb, and Cd amounts in the grain. Grain Cu content had strong relationship with irrigation regime. 50%-deficit irrigation minimized Pb and Cr contents in the grain.

Redesigning and monitoring groundwater quality and quantity networks by using the entropy theory.

This study aimed at redesigning and monitoring the groundwater network of Naqadeh plain in the southwest of Lake Urmia to examine the number and position of optimal wells for the salinity information transfer (EC) and survey of groundwater level at aquifer. In this regard, groundwater level data (35 wells) and electrical conductivity values (24 wells) were used during a 10-year period (2002-2012). In the first stage, simulation was conducted using the multivariate regression method and quantitative and qualitative values and the interaction of wells was observed. In the next stage, number of different classes was considered for clustering quantitative and quantitative values. The results of studying different classes of data clustering showed that the 12-class cluster had more accurate results based on the root mean square error and coefficient of determination. The root mean square error was improved by about 40, 21, and 15%, respectively, compared to the 3, 5, and 9-classe clusters. Finally, by choosing proper cluster of data, entropy indicators were investigated for quantitative and qualitative values at the aquifer level. The results of entropy indices at the aquifer showed that there was a severe shortage of information in terms of salinity in the Northwest of the aquifer, which necessitates drilling a new well in this area to accurately monitor the EC values. However, since more than 90% of the basin area is in surplus and approximately surplus conditions in terms of transferring information, the studied area has a good dispersion for qualitative monitoring. Information transfer index for the quantitative groundwater network monitoring showed that piezometers near Lake Urmia were faced with a lack of information, which according to piezometers ranking, is ranked last in terms of value of maintaining or keeping the network. Eastern areas of aquifer are also faced with shortage of piezometers accounting for about 3% of the total area. The results of survey of surplus wells in the aquifer showed that nine and six surplus wells are in the aquifer for the qualitative and quantitative network, respectively. There were also wells in which information transfer was not well done and their information could not be assured. Finally, based on the conditions, a new arrangement of wells and a new optimal network were proposed.