مجله ترویج و توسعه آبخیزداری
پیاپی 40 (بهار 1402)

The droughts of the last two decades have caused water shortages in the southeast of Iran, especially in the south of Sistan and Baluchistan province. Water supply is facing a high risk and one of the solutions to deal with it is water demand management. On the other hand, citrus fruits are one of the important agricultural products in the region, which play an essential role in the agricultural economy. Therefore, in the present research, the economic value and water demand function of these products have been estimated. The residual method, translog cost function and input cost share equations were used to estimate the demand function. The results showed that the real price of water is much higher than the price paid by farmers Also, based on the results, the highest degree of water substitution among the inputs is with seedling input (1.003), followed by animal manure (1.0007), chemical fertilizer (0.96) and labor (0.99). The results of the tests, to identify the infrastructure technology, indicated non-homotic, non-constant returns to scale and translog of production technology. According to the obtained results, it is suggested that the government can reduce the gap between the real price and the price paid by gardeners through appropriate price policies. Also, based on the results, the highest degree of water substitution among the inputs is with seedling input (1.003), followed by animal manure (1.0007), chemical fertilizer (0.96) and labor (0.99). The results of the tests, to identify the infrastructure technology, indicated non-homotic, non-constant returns to scale and translog of production technology. According to the obtained results, it is suggested that the government can reduce the gap between the real price and the price paid by gardeners through appropriate price policies.

The increase in population, greenhouse gases, temperature, and lack of an efficient management system affect the sustainability of watersheds and the emergence of significant problems in providing services in the watershed. Viability, contrary to livability, is an essential principle for restoring health and sustaining the sustainability of a watershed, for which a network between the dimensions and criteria related to viability should be considered. Concerning the measured dimensions of viability, most studies have investigated the ecological, economic, social, and infrastructure dimensions at the city and village scale. At the same time, there was no consensus about the criteria for explaining viability, and the examined criteria were basically in the category of areas of livability. Nonetheless, the concept of viability has yet to be considered to evaluate the system's ability to be in the range of resilience at the scale of the watershed. In this regard, the tensions in the watershed areas will be identified with a correct assessment and a complete understanding of the functioning of different watershed levels. In such a situation, by relying on resources and capacities, as well as learning how to deal with stress properly, it is possible to self-organize and restore the balance and stability of the watershed and ultimately improve the viability of the watershed and help improve the watershed’s viability by recognizing the measures priorities and designating the prevention approaches. In addition, this can be a helpful perspective for the executive directors to provide an appropriate managerial roadmap countrywide.

Environmental pollution with heavy metals is one of the inevitable human and environmental issues and threats that human societies are facing. The present research has evaluated the pollution level of Zoshk-Abardeh catchment basin with 11 heavy elements (Arsenic, Cadmium, Cobalt, Chromium, Copper, Iron, Molibden, Nickel, Lead, Vanadium and Aluminum). In this research, indicators such as enrichment factor, contamination factor, modified contamination degree, pollution load index, Geoaccumulation index and ecological risk index were used to measure pollution. The results of the calculation of the enrichment factor and contamination factor indicate that the studied elements have no enrichment or little enrichment in the region. According to the modified contamination degree, it can be said that all values ​​are below 1.5 and are in the category of no pollution to low pollution. The pollution load index also shows that the samples in the study area do not show any specific pollution. The results of the Geoaccumulation index indicate that all the studied elements in the study area have values ​​less than zero, which are in the non-polluted class. According to the coefficient of ecological risk potential, the basin has a low risk potential. The value of the ecological risk index was 87.13 that it can be said the ecological risk status of sediments in the studied area is low due to heavy elements. Considering that the study area is one of the target areas for tourism and human activities can increase the concentration of elements in sediments, protective and management planning should be done to control pollution.

Knowledge about vegetation cover and rangelands is the first and most important means of understanding rangeland ecosystems for proper management and optimal use of watersheds, accepted by all relevant departments in this field. This study was conducted in the Bahmai section of Kohgiluyeh and Boyer-Ahmad Province with an area of 1068.54 hectares to provide a suitable biological management plan for the restoration of the watershed according to the natural factors and ecological conditions of the region. After the integration of basic maps in GIS software, a map of biological operations was prepared based on the physical and ecological characteristics of working units. Planting, seeding, enclosure, intercropping, and conservation are for the study area biological programs that have been found suitable. The results obtained from the specifications of the working units of the basin were presented to decide and choose the best management plans according to the characteristics of the operational units by dividing the area of each management plan. Also, most of the area of the proposed operation is dedicated to grazing management and conservation, and due to the unfavorable conditions of the area for agriculture, agricultural lands have the lowest share in terms of area.

Today, watershed measures are used as a managerial and executive approach by managers and policymakers to deal with incidents affected by the destruction and improvement of watershed performance. Therefore, in this research, an attempt has been made to evaluate the effectiveness of engineering and biological measures planned in the Efin watershed located in Zirkuh county and south Khorasan province, Iran on hydrological variables and services. To do this, relevant information was obtained and used from relevant organizations. In this research, the changes of Curve Number (CN), Normalized Difference Vegetation Index (NDVI) and the slope of the main river were investigated and their effect on time of concentration, runoff depth and volume were determined. The research results indicate that after the implementation of watershed measures, CN decreases from 1.38% to 29.92% and NDVI increases from 42.44% to 87.50% and the slope of the main river decreases by 66.67%. The runoff depth and volume also decrease from 7.51% to 76.66%. The implementation of watershed management measures has played a different role in different sub-watersheds, and its effectiveness has varied according to the conditions and status of the sub-watersheds. Therefore, it is suggested that in order to achieve better management and more efficient implementation measures, the comprehensive watershed management with a health-oriented approach should be taken into account by officials and managers.

In order to closely monitor the state of groundwater resources and their optimal management, it is necessary to assess the fluctuations in groundwater levels, and then the influence of water quality. The current research was carried out with the aim of studying the fluctuations of groundwater level on its quality in Zarand watershed in Kerman province. For this purpose, the properties of 14 qualitative parameters of groundwater are studied, including the concentration of Na, K, Ca and Mg, the concentration of Cl-, So4, Co3-2 and HCO3 anions, SAR, sodium percentage, TH, TDS, pH and Ec for the area studied were assessed in the period from 2002-2003 to 2018-2019. Since the quality of groundwater depends on its quantity, changes in the quality parameters of water depending on the level of the aquifer were examined in the watershed. According to the results, there is a significant linear relationship between EC and TDS with R2 above 0.9. Monitoring salinity changes over time showed that the trend of salinity changes in this area increased over the studied period. To study the relationship between the qualitative parameters and the level of the groundwater table, the chemograph chart showed that the aquifer experienced a drop of 19.32 m, resulting in an increase in salinity of 229.37 µS/cm. The study of salinity and water level changes per year also shows a negative relationship (0.007) between the two parameters and is not acceptable from a statistical point of view. The results of this study can provide important information for the development of water management strategies and ensure sustainable management and safe use of water.

The sudden increase in population growth, followed by the restriction and scarcity of the world's supply of freshwater resources, has created new conditions for countries in the arid and semi-arid belts. To conserve, enhance and make the best use of these valuable resources, several projects have been implemented, including irrigation and drainage, flood control and dam construction. Meanwhile, dams are a very important tool to manage the river water for socio-economic development and also to improve the deteriorated ecological status of the river system and its services. Depending on place and time, dams play both negative and positive roles in environmental flows, with significant environmental costs. According to the results of the documents and reports, the construction of the dam has brought about environmental changes from various aspects of invasion and increase in invasive species to improving access to spawning habitats for migratory fish. The challenge for managers and scientists today is to better understand and manage the consequences of dam decommissioning. For this reason, the purpose of this study is to present the approaches of removing the dam on ecological changes. The results of this research can provide stakeholders in the responsible departments with valuable information about the changes in the behavior of dams on the environmental properties.