ghobad rostamizad; Mojtaba Pakparvar; parviz abdinejhad; Zahra Abdollahi; jafar khalafi
Abstract
Introduction
Evapotranspiration (ET) is one of the most important factors in the hydrological cycle and is a key determinant of energy equations on the earth’s surface. evapotranspiration estimates are important for hydrology, irrigation, forest and rangeland, and water resources management. The ...
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Introduction
Evapotranspiration (ET) is one of the most important factors in the hydrological cycle and is a key determinant of energy equations on the earth’s surface. evapotranspiration estimates are important for hydrology, irrigation, forest and rangeland, and water resources management. The evapotranspiration drives the soil water-energy balance which is largely used in general circulation models and climate modelling. Consequently, river water flow forecasting, crop yield forecasting, irrigation management systems, river/lake water quality are all dependent on evapotranspiration levels. For this reason, it is essential to accurately estimate the water budget. Numerous models have been developed to estimate evapotranspiration using remote sensing methods. The review of recent research shows that remote sensing and the use of satellite images have a high ability to estimate the amount of actual evapotranspiration.
Material and method
The aim of this study is calibrating the METRIC algorithm in estimating evapotranspiration in the Sohrin-Qaracheryan Plain, which is affected by flood spreading. This method has been used by many researchers around the world to estimate evapotranspiration. On the other hand, estimating the actual evapotranspiration is of great importance in the plains affected by the flood, especially in the Sohrin-Qaracherian Plain’s flood spreading. Therefore, in this research was conducted to estimate evapotranspiration using the metric algorithm in the Sohrin-Qaracherian Plain, for the optimization management of water resources in the region and regions with similar conditions. In this research, were used of the daily and hourly meteorological data of Zanjan Airport synoptic station from 2020 to 2021. These the data included minimum and maximum temperature, minimum and maximum humidity, wind speed average, sunshine hours and air pressure. To check the application of metric algorithm, were downloaded Landsat 8 images for 2020-2021 years and were done necessary corrections and preprocessing on them. Landsat images are available at 16-day intervals with a spatial resolution of 30 m and were obtained from the United States Geological Survey website (http://glovis.usgs.gov). After the images processing, is obtained the albedo, surface emissivity, land surface temperature, plant indicators, incoming-outgoing radiation fluxes, net radiation flux and the soil heat flux. Next, the sensible heat flux is calculated by determining the hot and cold pixels. Finally, evapotranspiration maps are plotted. In addition, for a better comparison of the results, were compared of the layers related to vegetation index include soil heat flux and land surface temperature in the different stages of the growth period. After extracting these indices, the evapotranspiration map was extracted using ENVI software.
Result and discussion
Results show that daily evapotranspiration increases is directly related with increase in vegetation density. at the initial of the growth period, the range of evapotranspiration is estimated between 0.08 and 4.97 mm.d-1, while this value in the middle and late of the growing season is estimated in the range of 0.086 to 5.56 and 0.59 to 9.57 mm.d-1 respectively. Based on the results of this research evapotranspiration obtained from the soil water balance model and METRIC model were estimated as 24115 and 25648 m3, respectively. The results validation of evapotranspiration obtained from the metric model was compared with the actual evaporation and transpiration obtained from the soil water balance model, and the error coefficient was obtained equal to 5.97%.
Conclusion
According to the results of this research, it was determined that the use of energy balance models using the science of remote sensing provides the possibility of estimating evaporation and transpiration regionally. On the other hand, the calculation error percentage shows that the metric algorithm is accurate enough to estimate ET in the studied area.
Alireza Rabet; Ghobad Rostamizad; Amin Salehpour Jam
Abstract
Introduction
One of the important problems in the process of implementing and maintaining watershed projects and natural resources is the lack of effective participation and cooperation of watershed residents. Based on this, it is necessary and inevitable to pay attention to the inhibiting factors and ...
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Introduction
One of the important problems in the process of implementing and maintaining watershed projects and natural resources is the lack of effective participation and cooperation of watershed residents. Based on this, it is necessary and inevitable to pay attention to the inhibiting factors and also to identify ways to strengthen the participation of local communities in the process of implementing watershed and natural resources projects. This research, was done with the aim of knowing the socio-economic characteristics of local communities, identifying indicators that are effective in reducing obstacles and increasing people's participation in the implementation of natural resources and watershed projects, knowing the expectations and needs of the local community and finally, scientific and technical solutions have been presented to increase the level of public participation in Arpachai pilot area of Zanjan Province .
Materials and methods
In this study, four influential indices, including social-cultural, economic, natural, and managerial, were identified and categorized with 40 sub-indices. Necessary information was collected through surveys, questionnaires, interviews, and multiple sessions with community members and local experts. The sample size was determined using the Cochran formula, and the collected data were analyzed using SPSS software. Also, to check the validity of the questionnaire from Cronbach's alpha, factor analysis was used in order to reduce and categorize the variables affecting people's non-participation in watershed management projects.
Result and discussion
The results showed that six factors explain 64.4% of the variance of the dependent variable and the education and information variable at the local level was recognized as the most effective factor that explained 29.97% of the variance of the dependent variable. Following that, the factors of improving the income and livelihood of villagers with 19.24%, diversity of economic activities and improving performance with 18.93%, strengthening the local economy with 13.92%, management of watershed projects with 11.34% and natural resources management with 4.3% were placed in the second to sixth priority, respectively.
Conclusion
In general, it can be said that the lack of information and awareness of the local community about the positive economic, social, natural and technical aspects and benefits resulting from the implementation of natural resources and watershed management projects in the area of their living and production is one of the important obstacles in the lack of participation and failure to achieve the anticipated goals in the implementation of watershed and natural resources projects in the study area. Based on this, attention and emphasis on the issue of building trust and increasing the level of social trust in the General Administration of Natural Resources and Watershed Management plays a significant role in the process of implementation and success of projects.
Jamshid Yarahmadi; Ghobad Rostamizad; Malek Rafieai; Karim Mehrvarz
Abstract
Since the most consumed water is in the agricultural sector, available water resources, especially in arid and semi-arid regions, are the main limiting factor for agricultural production. Therefore, by rain water harvesting systems and its proper management, it is possible to compensate part of water ...
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Since the most consumed water is in the agricultural sector, available water resources, especially in arid and semi-arid regions, are the main limiting factor for agricultural production. Therefore, by rain water harvesting systems and its proper management, it is possible to compensate part of water shortage in the mentioned region. The purpose of this study was to select the most suitable rain water harvesting techniques based on multi-criteria decision-making system using Analytic Hierarchy Process (AHP) and investigation of its effectiveness in supplying the water demand of pistachio gardens. The results of the AHP analysis indicated that the environmental impact criterion with a weight of 0.342 and permanency criterion with a weight of 0.284 were the most effective criteria for selecting of the best rain water harvesting system. Finally, the rain water harvesting system with geomembrane insulator with a weight of 0.371 was selected as the most suitable insulator cover, and two other rain water harvesting systems with plastic and isogam insulator were weighted with the weight of 0.350 and 0.279, respectively in the following priorities. Also, the results showed that from the insulated surface with an area of 800 m2 and an average annual rainfall of 300 mm, it is possible to harvest at least 200 m3 rainwater per year. With this volume of harvested water and the choice of drip irrigation with gravel filter, the annual irrigation water demand of 200 fruitful pistachio trees will be supplied during a crop season. Therefore, due to rainwater harvesting techniques, some parts of irrigation water demands of gardens will be provided in arid and semi-arid regions, as well as maintaining sustainability of production and increasing gardeners' revenues, the double pressure on surface water and underground water will also be reduced.
