Taher farhadinejad; iraj vayskarami; Mehran Zand
Abstract
Introduction
Drought can have serious negative effects on the quality of water needed for irrigated agriculture. The geological formations of the region increase the concentration of minor and rare toxic elements in the waters, and on the other hand, human activities lead to water pollution in the ...
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Introduction
Drought can have serious negative effects on the quality of water needed for irrigated agriculture. The geological formations of the region increase the concentration of minor and rare toxic elements in the waters, and on the other hand, human activities lead to water pollution in the nearby areas. In this research, the effect of drought on the quality of surface water, the effect of various factors such as geological formations and the decrease or increase of rainfall and air temperature on the quality of water resources, how the quality of water changes, determining the limits of water consumption in the drinking sector and agriculture should be paid.
Materials and methods
The Tirah River Basin with an area of 3243.6 square kilometers is considered as one of the sub-basins of the Dez River and a subset of the Karun Basin. The Standardized Precipitation Index (SPI), Standard StreamFlow Index (SSI) and Decimal Index (DI) were used to calculate standard drought indices. Elements and compounds of electrical conductivity (Ec), Total dissolved solids (TDS), pH and Anions of chlorine (Cl-), Sulfate (SO42-), Bicarbonate (HCO3-), Sodium (Na), Calcium (Ca) and Magnesium cations (Mg) were investigated. To draw the pattern of droughts, 3 hydrometric stations of Teng Mohammad Haji (upstream), Rahimabad Silakhor (middle) and Tir-Droud (outlet) stations were tested.
Results and discussion
The most severe hydrological droughts with a duration of 2 years and a minimum SSI value of -1.23 in the Teng Mohammad Haji Station in the water years of 2009 and 2010 and the Tir-Droud Station with a duration of 4 years (-1.19) and the Rahimabad Silakhor Station with a duration of 3 years (-1.16) occurred for the water years 2012, 2013, 2014 and 2015. The analysis of discharge and precipitation data of Teir sub-basins showed that between the discharge and precipitation (SPI and SSI) of Tang Mohammadhaji and Rahimabad Stations, there was an average positive correlation at a significant level of 0.05 (R2=0.526). Examining the relationship between annual discharge and water quality parameters showed that there was a negative correlation for most parameters such as TDS, EC, chlorine, the total of anions and cations, so that the maximum concentration of quality parameters occurred in droughts. In Tang Mohammadhaji Station, the highest percentage of changes was related to sodium and chlorine, respectively, with 62.55 and 39.70% in dry years compared to the long-term average. The results of this research showed that the percentage of changes in calcium, magnesium, sodium, carbonate and chloride
increased in dry years compared to the long-term average in the studied stations in the Tirah River Basin. All the stations in the Tirah Basin have passed the period of relatively dry hydrological drought (-0.84 to -1.28) and none of them have suffered severe hydrological drought.
Conclusion
The analysis of discharge and precipitation data of dark sub-basins shows that between discharge and precipitation (SPI and SSI) of Tang Mohammad Haji Station, which is an upstream sub-basin of dark, there is an average positive correlation at a significant level of 0.05 and in Rahim Abad Station, which is in the middle of the basin It is located in Tire, and according to Pearson, it has a correlation at a significant level of 0.05 at the exit station of Tire basin, no significant correlation is observed between discharge and precipitation variables, which can be caused by snowfall and the persistence of snow in the heights from the previous water year, the construction of Meruk Dam. In the upper part of the basin, as well as the water intake of Bishehdalan Silakhor Wetland in droughts and abundant water harvesting from the Tirah River for agriculture. The upstream basin of Tang Mohammadhaji Station is completely calcareous, which has caused changes in parameters of calcium, TDS, EC, etc. In Rahimabad Silakhor Station and Tire outlet, half of the area of the basin is dedicated to intrusive rocks such as granite and granodiorite, which increases potassium and calcium. In the studied stations in Tirah River Basin, the percentage of changes related to calcium, magnesium and sodium, and carbonate and chlorine anions have increased in dry years compared to the long-term average. In general, it can be concluded that drought can have negative effects on water quality parameters in Tirah River Basin.
kianfar payamani; Ebrahim Karimi Sangchini; iraj vayskarami; Mehran Zand
Abstract
IntroductionManaging a pervasive and effective phenomenon such as drought in different sectors of the economy requires close cooperation and careful planning. Lack of strategic drought planning and delays in decision-making have increased costs to reduce drought damage. The aim of this study was to develop ...
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IntroductionManaging a pervasive and effective phenomenon such as drought in different sectors of the economy requires close cooperation and careful planning. Lack of strategic drought planning and delays in decision-making have increased costs to reduce drought damage. The aim of this study was to develop strategic for drought adaptation using the SWOT model in Lorestan Province. Materials and methodsIn this research, the methods of reviewing sources and interviewing with a questionnaire were used in order to provide macro strategies to adapt to drought. For this purpose, the current status of ecological resources, environmental changes, economic sectors and their dependence on water resources, population and employment, management of ecological resources, organizations and institutions were analyzed, then by reviewing the upstream laws and documents, interview with resource managers, local and national decision makers, experts, published background and other available information identified the causes of problems and obstacles to drought management in the province. The statistical sample consisted of 27 experts and scientific and executive experts were selected. Scoring was done on two occasions by experts, and finally, by averaging the opinions of experts and scientific and executive experts, the weight of internal and external factors was determined. In the final stage, in addition to identifying important factors in each of the criteria of strength, weakness, opportunity and threat, necessary management strategies were determined based on the conditions of Lorestan Province through SWOT analysis. These issues were categorized in the form of environmental opportunities and threats and internal strengths and weaknesses, then analyzed by SOWT analysis approach and Delphi method. Results and discussionThe study of strength factors shows that the existence of companies and organizations with resource monitoring units in the province with a weight of 0.25 has a higher effectiveness and degree of importance among other factors. Lack of proper planning and organization for monitoring and evaluation of drought weighing 0.33 has a very high effectiveness among the factors of poor adaptation to drought in the province. Among the opportunities, the factor of technological advances in the field of precision agriculture with a weight of 0.1 have a very high effectiveness. The factor of endangering the livelihood of farmers in case of drought is the most effective among the studied factors of threats with a weight of 0.22. Factors of irrigation of lands in some areas with polluted water and gradual destruction of agricultural soil and population increase and as a result increase in demand for water with a weight of 0.02 were recognized as having the least effectiveness among the threats of drought adaptation in Lorestan Province. ConclusionAfter scoring using the Delphi method, it was found that the presence of faculties and centers of agricultural education and natural resources in Lorestan Province was recognized as the most important strength. But despite this strong point in the province, unfortunately, the lack or inappropriateness of available data and information for the purpose of monitoring and evaluating the effects of drought is known as the main weakness. According to these results, in the direction of the conservative strategy, the strategy of balancing aquifers with the priority of aquifers with a negative water balance was suggested. The government's support for water harvesting projects at the level of cities and villages and the monitoring of better water management in cities provide suitable opportunities to improve the ability of farmers to deal with the negative effects of drought. The final result has been the presentation of drought coping strategies for different regions of the province in the areas of surface and groundwater supply, irrigated and rainfed agriculture, urban and rural drinking water and river water environment.
