نشریه مدل سازی و مدیریت آب و خاک
سال دوم شماره 1 (بهار 1401)

In the present study, the Qarah Tikan river basin in particular the subbasin of Qarah Tikan Village has been studied. This is located in the northeast of Iran in proximity to Turkmenistan and among the basins without ground station data. IMERG-Final satellite precipitation products, ERA5-Land reanalysis temperature and GLEAM evapotranspiration were used to identify and evaluate the basin. The evaluation results showed that the reanalysis temperature product has high accuracy in temperature estimation and the satellite precipitation product has a high correlation with precipitation data. Therefore, the combination of satellite products with ground station data leads to proper runoff estimation in ungauged basins and hydrometric stations. Based on this, estimating the amount of water available in the basin in different months indicates the possibility of storing about 11.8 million cubic meters per year to meet the needs and agricultural development of the region. 

In this study, in the Qarah Tikan basin, as ungauged basin in the general water balance equation was used to calculate the available water. In this equation, GLEAM global data (Shiklomanov, 2000) used for actual evapotranspiration and environmental needs obtained by the Lyon method were considered as output components of basin. In addition, the inflow to the basin, which was obtained from the hydrometric station of the upstream basin, and the precipitation, which was obtained from IMERG-Final-V06 (Huffman et al., 2019) satellite data were considered as the incoming components to the basin. To calculate the environmental needs of the Lyon method, the monthly runoff of the basin is required for which Justin's experimental method was used. As input data for Justin's experimental method, monthly runoff with adjacent basin from the hydrometric station and precipitation of the basin, monthly temperature of IMERG-Final satellite precipitation data and ERA5-Land were used espectively. By using ArcMap and DEM the slop and area of the basin was produced. 

The results of evaluating monthly temperature data showed that these data have a high ability to estimate the temperature and is reliable in remote areas where there is no weather station and ungauged basin. According to the comparison of satellite precipitation data and ground stations, it can be said that although they do not have high accuracy in estimating precipitation, but they have a good correlation and estimate precipitation with appropriate accuracy. Precipitation in 3 stations is underestimated and overestimated in 2 stations. Based on the long-term average, the annual rainfall of the basin is about 225.9 mm. On the other hand, a study of evapotranspiration data from the GLEAM shows that the long-term annual average is about 194.4 mm, which peaks in the spring due to greater access to water and rising temperatures. Thus, about 86% of the basin rainfall in the evaporation process is out of reach. The annual inflow to the basin was about 15.9 million cubic meters and the annual runoff from rainfall in the basin according to the Justin method was about one million cubic meters. Furthermore, with the aim of maximum sustainable use of basin water resources, the outflow runoff of the basin was considered equal to the downstream environmental needs. Thus, based on the Lyon method, the annual environmental need to maintain the stability of the river was determined to be about 7.5 million cubic meters. As a result, in terms of rainfall, runoff, evapotranspiration and environmental needs, the annual amount of water available in the basin for different purposes is about 11.8 million cubic meters. 

In this study, the distribution of these water resources in different months has been determined and the results indicate that to meet the demand of the agricultural sector in summer and also control winter and spring floods, planning for the design and construction of a storage dam should be on the agenda. In this case, the output of the basin will be adjusted. Once again emphasizes the importance and ability of remote sensing and GIS in the study of water resources in ungauged basins without proper ground station statistical data.

Assessing the quality of water resources, especially drinking water resources, has been of great importance in recent years, along with the per capita reduction of available water resources. Water quality index for drinking and irrigation expresses the total quality of water through a single number at a specific time and place based on various water quality parameters. In this study, the quality of water resources in Varamin Plain was studied using water quality index (WQI) over a period of 10 years.

Varamin plain is located 45 km southwest of Tehran and at an altitude of approximately 1000 meters above sea level. Its alluvial plain area is about 138,000 ha, of which more than 50,000 ha are agricultural lands. In this research, data from 35 qualitative data samples including pH, total dissolved solids (TDS), EC, Calcium, Potassium, Sodium, Magnesium, Bicarbonate, Chlorine and Sulfate have been studied. Also, using Pearson correlation, the relationship and the effect of the parameters on each other were investigated. These samples were prepared from different parts of Varamin Plain in a period of 10 years (2008-2018) and the concentration of parameters affecting the quality of groundwater resources was investigated. In this study, ArcGIS 10.5 software was used to prepare spatial distribution maps and SPSS software was used for statistical analysis.

According to the WQI in 2008, 51.42% of the region has inadequate water, which in 2018 has decreased to 45%. Also, calcium, sodium and chlorine have a positive and significant correlation with TDS. According to the spatial distribution map of Varamin Plain in 2018, it has more area with suitable quality, while the southern and southwestern part of the region, despite improving the water quality of the region, still have unsuitable quality for drinking. The WQI spatial distribution maps show that the area percent of good class of WQI in 2018 has increased compared to 2008. In both years, the southern and southwestern regions are in poor condition. The high concentration of TDS and EC in some places was due to land use change, wastewater discharge, ecogeomorphological factors, as well as over-extraction of groundwater resources. Good quality range in 2008 is in the central areas, which in 2018, these areas include most of the central and eastern regions.

In general, the results of this study showed that currently the values of a number of effective parameters in determining the quality of groundwater resources such as TDS and EC in most sampled areas and also the pH value in some sampled areas of Varamin Plain has exceeded the standards. In addition, groundwater quality has slightly improved during the study period (2008-2018). Thus, considering the widespread impact of human factors on reducing the quality of groundwater resources in Varamin Plain and the severe rate of groundwater abstraction, careful study of illegal wells in the region, quality protection of groundwater resources and management of exploitation wells and the use of appropriate irrigation systems, proper harvesting as well as proper drainage of agricultural lands is essential in future plans.

Measuring complexity and ways to reduce it in organizations and decision-making processes has become one of the topics of the day. The chaos theory was proposed in the 1960s, and the most effective and most successful effort was made by Edward Lorenz. Towards this, the flow rate of Sefidrood River as the most important river in Guilan Province and the second-longest river in Iran was studied using Chaos theory.

The study area in this research is a sub-basin of the Sefidrood River Basin. After collecting the monthly and annual discharge data of Sefidrood River, the following items were investigated:1- chaotic dynamic systems, 2- phase space reconstruction, 3- determining the time delay, 4- determining the embedding dimension, 5- determining the correlation dimension, and 6- determining the Lyapunov and Hurst exponents.

In determining the delay time using the autocorrelation function (ACF( curve, the appropriate lag is where the graph reaches a value close to zero or about 0.1 to 0.2. An appropriate embedding dimension is an embedded dimension in which the number of false neighbors has reached to about zero. For a lag of 1-month, the delay vectors are concentrated around the diagonal axis of space. Therefore, X(t) and X(t +1) are very close and continuous. Therefore, they will cause the characteristics of the adsorbent structure to be lost. Also in the state (phase) space for the delay time of 100 months, the density of lag vectors is close to the horizontal and vertical axes of the graph and indicates the incoherence and complexity of successive components in the lag vectors and its inadequacy to achieve system dynamics. However, due to the 5 months delay state space obtained from the average actual information (AMI) method, the delay vectors have a better distribution and the state space is well filled with points. The correlation dimension of the monthly time series is 3.37.

The presence of stochastic behavior in the river flow was determined using the correlation dimension test and Hurst exponent. The correlation exponent was saturated after increasing the embedded dimension in an incorrect value equal to 3.37. In addition, the closest correct value to the correlation dimension indicates the minimum variables required to describe the system, which is a value of 4. The obtained Hurst exponent is opposite to 0.5 and according to Hurst studies, it indicates the non-randomness and the presence of chaos in the river. The Hurst exponent obtained in daily scales is between 0.5 and 1 and indicates the existence of long-term memory in this series.

Due to urban development, it is necessary to provide management solutions to reduce the risk of flooding of urban facilities. Passive defense is a new approach aimed at minimizing and preventing financial and human losses and preventing potential crises based on the civilian methods. Among the various models proposed for strategic planning, the SWOT matrix is the most common. The main purpose of this study is to provide the best management strategies to reduce the risk of existing facilities and also to provide strategies for facilities that will be constructed in the future.

The infrastructure map of Kashan City (urban land use) was prepared via Kashan Municipality. Then, the infrastructures (applications) were divided into 14 general categories. In the next step, by carefully examining the area and field visit and examining each infrastructure, a list of internal factors (strengths, weaknesses) and external factors (opportunities and threats) was prepared and the final score of the weight multiplied by the rank for internal and external factors. Achieved and strategic position for the region was identified and management strategies for the region were developed. Finally, the developed strategies were prioritized using the Quantitative Planning Matrix (QSPM).

The final score of internal and external factors was equal to 1.931 and 2.03, respectively, which indicates the predominance of weaknesses in internal factors and the majority of threats in external factors. The strategic position for the study area is recognized as the defensive strategy (WT) type. three strategies include: 1- providing the necessary budget for strengthening urban infrastructure with a passive defense approach against floods and anti-flood action of urban facilities, 2- interacting with scientific centers for studies in the context of floods and the damages caused by it, and 3- principled constructions with the focus on sustainable development and passive defense were developed. The results showed that the strategy No. 3 with a final attractiveness score of 6.51 is the first management priority for urban infrastructure. The strategies 1 and 2 with the final attractiveness score of 4.59 and 4.15 are proposed as the next managerial priorities for the region.

According to the score of internal and external factors, the strategic position was obtained as defensive type. Passive defence tries to neutralize the weaknesses and threats in the region by relying on the strengths of internal factors and the opportunity of external factors. According to the result of the Quantitative Planning Matrix (QSPM), construction with a focus on sustainable development and passive defense with respect to the river area was selected as the initial strategy for the region.

Water supply and proper management of water resources is one of the serious challenges of water managers and researchers. The optimal management and finding suitable solutions in arid and water scarce areas to satisfy the human needs requires a careful attention to the optimal allocation and prioritization of water consumption among different sectors. Competition over water consumption in different sectors is one of the main causes of conflict and ultimately more exploitation of water resources and the resulting problems. Many regions of the world face significant challenges in freshwater management. Limited water resources allocation, environmental quality, and sustainable water use policies are growing concerns. A comprehensive water resources management approach is essential in different climatic and socio-economic conditions.

In this study, the availability and uses of water resources in Qazvin plain were evaluated using WEAP simulation model platform. The components of the hydrological cycle and rainfall-runoff process have been simulated using WEAP model at the watershed scale. Toward this attempt, different management scenarios regarding the reduction in the amount of demand for agricultural, drinking and industrial water have been developed. Also, increasing the water use efficiency and reduction in water losses were proposed. Finally, the effects of management scenarios on water resources were compared over the study area. Also, the results of proposed scenarios have compared with the continuing the current condition as a base case scenario.

The results of the reference scenario showed that groundwater storage has a declining trend and the largest decrease has been occurred during 2017 and 2018 years. The amount of decreasing water resources was approximately 400 million cubic meters. While, according to the increasing groundwater storage and efficiency improvement scenario, the increase in the amount of available water will be equal to 1500 Million cubic meters increases. Comparing the amount of unmet demand between the two scenarios showed that in the scenario of increasing irrigation efficiency, the amount of water demand in the study area will decrease by about 40 million cubic meters.

The present study showed that through applying appropriate management measures in the region, it will be possible to rehabilitate groundwater resources and the current situation of the water crisis will improve. Otherwise, valuable groundwater resources in the study area will be seriously threatened and irreparable consequences such as degraded groundwater quality, land subsidence, drying or reduced well discharge will occur. Therefore, a balance between exploitation and available water resources in the study area is essential. According to the results, the replacement of modern irrigation systems with traditional irrigation methods in the Qazvin plain will reduce the loss of water resources. In addition, solutions such as artificial aquifer recharge can be considered in the restoration of water resources. Accordingly, conservation of water resources is necessary by implementing practical solutions due to the drought and water shortages in the region. the study of hydrological effects of water resources development plans using modeling approaches should be considered.

Today, climate change is one of the issues that has always been the focus of the world. The use of general circulation models (GCM) is one of the most reliable methods for simulating climate variables in future periods. One of the influential factors in plant growth and yield is temperature. Therefore, in this study, the future temperature trend in Abhar Plain under the influence of climate change during future periods was investigated to study the effects of climate change on tomato yield.

The current study tried to simulate the tomato yield using the AquaCrop plant growth simulation model. We used synoptic stations of Khorramdareh which was located at a very short distance from Abhar (6 km) in the central part of the region and it had a similar climate to Abhar. The minimum, average and maximum temperatures measured at Khorramdareh Synoptic Station were used in the period of 1991-2010. LARS-WG software and A2 climate scenario and Hadcm3 model were also used for climate simulation. Then, using plant yield simulation by the AquaCrop model, plant yield was simulated and estimated in future periods and at different cultivation times. In this study, the observation period of 1991-2010, near future (2011-2030), middle future (2046-2065), and far future (2080-2099) have been considered.

The highest yield in tomato crop cultivation at present is related to 5 June (15 Khordad in the Solar year) cultivation with 55.57 t ha-1. Since the conventional planting time in the Abhar region is 26 May (5 Khordad in the Solar year), with 10 days of transferring the conventional cultivation time to 5 June (15 Khordad in the Solar year), the yield will increase by 0.51 t ha-1. Tomato yield will also increase over the next horizon, which may be due to the plant's C3 photosynthetic system and premature fruiting and flowering.

The LARS-WG model in predicting minimum, average, and maximum temperature, it shows an increasing trend in the future. The values of maximum and minimum temperature in the middle future will be higher than in the near future and the far future will be higher than the middle future compared to the observed period. The highest yield in tomato crop cultivation at present is related to 5 June (15 Khordad in the Solar year), cultivation with 55.57 57 t ha-1. Since the conventional planting time of the study region is 26 May (5 Khordad in the Solar year), with ten days of transferring the conventional cultivation time to 5 June (15 Khordad in the solar year), the yield will increase by 0.51 57 t ha-1. Tomato yield will also increase over the next horizon, which may be due to the plant's C3 photosynthetic system and more early ripening and flowering.