Sustainable use of limited water sources has great importance in agriculture sector as the largest water consumer (90-95 percent). According to economic theories, we can use stability as an index in agricultural systems management by quantifying agricultural water stability. Multipurpose non-linear fractional programming model is applied method of studying sustainability of agricultural systems that evaluates and compares different indexes imposing equal weights. Because of the importance of the agricultural consuming water rate, stability indexes of ratio of gross income to water usage (3.06, 0.530) and ratio of employment to water usage (0.265, 0.072) were calculated in two scenarios in agricultural year 2006-07 in Marvdasht town. Crop water consuming may be reduced through new irrigation technology and increasing irrigation efficiency that in turn increase these indexes and indicates movement in agricultural water stability.

Iran is facing severe water shortage.Modernization of irrigation systems and improving the efficiency of water use is typically presented as an opportunity for large water saving in the agricultural sector. For this reason, the Iranian government strongly supports the modernization of irrigation systems and has implemented many water-saving irrigation measures with the objective of improving water productivity and reducing agricultural water use. In this regard, some progress has been made. But total agricultural water use did not decline as expected. Thus, agricultural water use in Iran may experience a rebound effect. The hypothesis of a rebound effect as a consequence of water saving investments is taken from the Jevons paradox in energy economics. The objective of this study was to evaluate the magnitude of the water rebound effect (WRE) at farm level in Bakhtegan basin using corrected land allocation model and direct comparison approach. The results indicated that the magnitude of the agricultural WRE in Bakhtegan basin can fluctuate between 10.1% and 109.38%.

Rural industrialization strategy has a significant role in achieving national development goals. Spontaneous establishment of industrial units in proximity of Kamard village has various environmental and socio-economic consequences and impacts for the area, so an examination of these is necessary on regional and local scales. Research methodology is observation and library research and we use economic basis for the analysis of local employees and to derive a locational coefficient for industrial groups currently present in Kamard industrial zone. The results show, during 2001-2005 the total number of industrial units remained unchanged but diversity of industrial groups reduced and just four industrial groups remained in basic industries. Generation of the environmental pollutants endangers human health and environmental vitality, such that drinking water and agricultural water contamination are respectively 50 times and 25 times higher than the COD standard. Generation of 431 job opportunities per annum provides employment and income for the local and non-local population, in so far as non local employees are three times more than local employees in basic industries.

A system dynamic model is necessary to estimate the existing interactions between Urmia Lake and factors affecting it. In this study, the Predator-Prey model using system dynamics simulation has been developed for Urmia Lake Basin. The main advantage of this model is providing the balanced water allocation between stakeholders in order to have a sustainable water management system for the lake. Due to increasing the area of irrigated lands in the northwest of Iran, having an applicable and up-to-date method to reduce water consumption in agricultural part is unavoidable. A stock-flow model has been designed in this study, in which Urmia Lake and irrigated lands are considered as the prey and predator, respectively. Then, the effects of various factors on the water elevation fluctuations of the lake have been analyzed dynamically and the strategies for reducing the water consumption of agricultural part have been investigated carefully. The results of this study indicate that the reducing irrigated lands by 40%, improve irrigation efficiency by 21% and reducing the area of lake by 20% lead to increasing water level of the lake by 1.7, 0.8 and 0.5 meters, respectively. By applying these policies, the water level of the lake will increase about 4.3 meters and it will lead to better ecological condition.

This study aimed to determine the optimal cropping pattern and the optimal amount of water usage emphasizing on sustainability of water resources and optimizing the economic and environmental factors in Fariman-Torbatjam plain. In the first section of this research, the status of sustainability of water resource were analyzed using the sustainability indices and calculation the water balance of underground water in wet, normal and dry water years. Considering that the study aimed to propose the optimal crop pattern by emphasizing on agricultural sustainability and water resource along with maximizing gross margin, the Multi Objective Programming Models like Multi Objective Fractional Programming must be employed. The defined goals of this model are maximizing sustainable indices which involve the ratio of gross margin to water resource usage, chemical fertilizers and pesticides. By implementation of the optimal cropping pattern, the usage of water, chemical fertilizers and chemical pesticides compared to the current crop pattern will decrease by 10, 5.11 and 12.52 percent respectively and gross margin will be increased by 0.6 percent. Also, sustainability index of water, chemical fertilizers and chemical pesticides compared to current cropping pattern, will be increased by 11.78, 6.02 and 15 percent. In order to achieve to the quantitative sustainability of water resources, the ratio of water usage in agricultural sector to renewable water was used. With the implementation of the proposed optimum model, the water consumption will be reduced by 10 percent yearly, then the amount of water usage in agricultural sector in sudied area will be decreaesd by 0.7 of renewable water in 8 years, and then the quantitative and qualitative of sustainability of water resources will be achieved.

Determination of agricultural water consumption, as the main consumer of the country's water resources, is very important in order to plan and manage resource consumption and establish food security, water security and improve the livelihood of the growing population. Water consumption or actual evapotranspiration is the part of water used or delivered to the agricultural sector that is out of reach and cannot be reused. Estimating the spatial distribution of actual evapotranspiration (ETa) based on valid satellite data is a new approach in planning and determining water balance. In the study, amounts of actual evaporation, transpiration and evapotranspiration in the country and agricultural, horticultural and rainfed land uses were extracted using the methodology introduced by Food and Agriculture Organization (FAO), which is presented in the WaPOR database. The results showed that the highest actual evapotranspiration about 2500 mm occurs on the north coast and Lake Urmia. The results showed that the average amount of actual evapotranspiration in irrigated horticultural lands was 299.30 mm and in irrigated agricultural lands was 301.52 mm in a 12-year period. Accordingly, the amount of actual evapotranspiration of irrigated lands on a national scale and for the year 2018-2019 was calculated to 28.84 billion cubic meters, which is equal to 20.78 and 8.06 billion cubic meters for agriculture and horticulture, respectively. Furthermore, 72.1% of that belongs to transpiration and the other of that 27.9% belongs to evaporation.

Fyrouzeh mine is located about 55 km northwest of Nyshabour in the Provice of Khorasan Razavi. The exposed rocks are mainly volcanic and intrusive with intermediate composition and all of them are altered. This mine is the first type of IOCG reconized in Iran with Cu-Au-LREE-U. Besides Cu-Au-U, this area shows As, Mo, Zn and Th anomalies. Geochemical evaluation of stream sediment with regard to environmental concern revealed high Cu anomalies.  Rocks show high uranium anomalies (up to 35 ppm) higher than the standard values (1 ppm). Airborne radiometric maps show high U and Th anomalies in a broad area. Ag, Hg and Mn show anomalies within the stream sediments. Cu, Pb, Zn, Ag, Ni, Mn, Sb, Hg, and U content of both drinking and agricultural water are fourtunatly within the range of standard, only two samples have higher As content (more than 10 ppb).  High level of U-Th radiation and contamination of stream sediment with respect to Cu, Hg, Ag, Mn and agricultural water to As are important environmental issues and people health therefore they need to be study.

Management of agricultural practices plays a vital role in reducing the use of limited water resources in arid and semi-arid regions which could result in their sustainability. In this research, the role of managing agriculture in sustaining flow of Zayandeh-rud was studied by calculation of rice water requirement (actual evapotranspiration) in paddy fields of Zarrin-shahr by using method of FAO-56 and comparing the results assuming a shift in cropping pattern from rice to other crops. Rice water requirement was estimated at 1485 mm and the volume of water required for irrigation of paddy fields with area of about 6630 Hectare was estimated at 77 MCM. Volume of irrigated waterwas also evaluated by water balance method, confirmed the reliability of FAO-56 method. The results show that, replacing rice or wheat-rice cropping pattern with some possible crops such as bean, maize, walnut, apple and grape decreases irrigation requirements about 27, 15, 24, 29 and 40 MCM, respectively. Generalizing results for the total paddy fields in Isfahan Province with estimated area of about 20000 Hectare will result in an increase of about 3.4 to 9.1 m3/s in Zayandeh-rud discharge during critical months of June to October, when the river flow highly decreases, causing sustainable flow of the river through the year.

About two-thirds of rivers, lakes and groundwater are applied for agricultural production in the world. Same as other countries, a significant fraction of surface and groundwater resources are used in agricultural sector in Iran. Water balance at country scale is the origin of estimation of applied water as agricultural consumption. The variability of annual precipitation is as the origin of the components of water balance in hydrological cycle, caused changeability in the water consumption of agricultural sector which are important reasons for estimating and re-estimating consumptive water in agricultural sector. Therefore, in this study, consumptive water of agricultural sector was analyzed based on long term (50 years) and short term (current 7 years) measured data for precipitation with the method of water balance in hydrological cycle in the country. Results revealed that average annual precipitation were 249±53 and 206±33 mm for two long and short studied periods, and the consumption water in agricultural sector were 67 ±18 and 83±6 km3 for long (50 years) and short (7 years) periods for non-modified conditions. The modified consumption water for the short period was 75±6 MCM.Results revealed that for the long period, the water consumption in agricultural sector was 0.50 of renewable water in the country. The outstanding of this study was up to date estimating of the water consumption in agricultural sector and its analysis. But applying water balance method for this purpose has some substantial limitations and non-reliable simplifications. Therefore suitable experiments are needed to reliably the results.

Achieving food security in the future with sustainable use of water resources will be a big challenge for the current and future generations. Population increase, economic growth and climate change intensifythe pressure on existing resources. Agriculture is a key consumer of water, and it is necessary to closely monitor water productivity for it and explore opportunities to increase its productivity. Systematic monitoring of water productivity through the use of remote sensing techniques can help identifying the gaps in water productivity and evaluate appropriate solutions to address these gaps.
 
Qazvin plain is known as a hub of modern agriculture by providing about 5% of the country's agricultural products. Therefore, estimating water demand and water productivity in agricultural management in the region is considered important and necessary. In order to monitor water productivity through access to various data across Africa and the Middle East, the WaPOR database provides the possibility to examine the rate of evapotranspiration, biomass and gross and net biomass volume productivity based on the land use map in the period of years 2009 to 2021. In this database, it is possible to check the mentioned items at three levels with different spatial resolution, which according to the scope of the study, it is possible to check values with a spatial resolution of 250(m). In order to determine the efficiency and accuracy of the land cover classification map of the WaPOR database, the results obtained are examined and compared with the Dynamic World model, which represents a global model with high accuracy. For this purpose, the latest land use map related to 2021 Using the WaPOR database and Dynamic World in the GEE system, it was prepared and based on the classification of the region in order to check the accuracy of the user map of the WaPOR database and to determine the percentage of each class compared to each other. Finally, all estimable indicators were calculated and checked by the WaPOR database during the years 2009 to 2022.
 
The amount of evapotranspiration of the plants covered by the irrigation network in the period of 2009 to 2016 has been associated with a relatively stable trend, but this trend has decreased in 2017 onwards, which is one of the reasons for the decrease in the amount of evapotranspiration in this the period of time and can refer to the lack of water available to the plant due to the limited water resources in recent years. The investigation of the total amount of biomass in different lands shows that during the years 2009 to 2022, this index has been accompanied by a gradual increase in all uses, so that the amount of TBP index in 2020 was 17% more than in 2009. It shows the amount of biomass in different lands. The amount of biomass in the lands covered by the water network is 5 to 6 times higher than that of the rainfed lands. Among the influential parameters in estimating the TBP index, we can mention the amount of evaporation, transpiration, and transpiration, the increase or decrease of each of these parameters will have a significant impact on the estimated amount of biomass. The results showed that the amount of biomass production in the areas covered by the irrigation network largely depends on the high transpiration rate in these areas. From the beginning of 2009 to 2016, the gross amount of biomass water in the lands covered by the irrigation network has been accompanied by an increase, but in 2017, drastic changes in the process of underground changes will decrease the area of the lands covered by the network and many of these lands. It has been turned into fallow and rainfed lands. The analysis of NBWP index also showed that the amount of net productivity in rainfed lands is strongly dependent on the annual increase rate, and much of the crop yield in rainfed lands is dependent on the amount received. Among the influential parameters in estimating the total amount of biomass, we can mention the amount of evaporation, transpiration and transpiration, the increase or decrease of each of these parameters will have a significant impact on the amount of estimated biomass.
 
WaPOR database data can play an important role in estimating the rate of delayed transpiration and parameters related to water productivity in the region due to its ten-day spatial resolution and the absence of data gaps. In general, the WaPOR database can be used as a guide in the reliable determination of evapotranspiration values and planning related to water resources in the agricultural sector.