Adel Khazaei; Majid Abaspour; Sasan Babaei Kafaky; Lobat Taghavi; Yousef rashidi
Abstract
Introduction: The metropolis of Tehran as the largest capital of the Middle East is faced with phenomena such as environmental degradation, land use change and high concentration of agricultural and industrial disasters. Knowing the changes of land use in the past and predicting its future status is ...
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Introduction: The metropolis of Tehran as the largest capital of the Middle East is faced with phenomena such as environmental degradation, land use change and high concentration of agricultural and industrial disasters. Knowing the changes of land use in the past and predicting its future status is necessary in order to carry out a principled, dynamic planning. In this study, the spatio-temporal dynamics of land use changes in the Tehran in a 20-year period and the prediction of future changes in these land uses in the next 40-year were selected as the general objectives of this study.Material and Methods: After forming a database of Landsat 5 and 8 satellite images for three times of 2001, 2011 and 2021, the land use map of this times were prepared. For the validation of the maps Google Earth images, ground points and accuracy and Kappa coefficients were used. The time period from 2021 to 2061 was considered to predict future changes. In order to zoning and predict the future of land use changes, 6 land use change transfer sub-models with artificial neural network, Markov chain, and LCM model were used. Evaluation of the accuracy of the model was obtained from the comparison of the ground map of 2021, the future map of 2061, and the values of Null success, success, Miss and False Alarm were obtained.Results and Discussion: The results showed that the period from 2001 to 2021 was associated with the expansion of residential areas, the growth of urban areas and the reduction of green spaces including gardens and parks. The expansion of residential areas has been primarily in poor and barren soils and then in gardens and green spaces. This urban growth was clearly in region 5, 21, 22 and its physical development process was linear. The decrease in the level of gardens and green space is very catastrophic and this decrease is especially evident in the central areas of the city due to the high density of buildings. Urban parks are clearly in a complicated condition in the eastern areas of Tehran. The area of rain fed agriculture has increased and the area of barren soils and poor lands has decreased. Most of the changes in land use related to low capacity lands and agricultural lands have occurred. Studying the maps of the future of land cover showed the continuation of the same trend of the past 20 years. Although the growth of residential areas will be slower than the previous period, but the capacity and dimensions of the city will continue to increase, especially in the western, southern and southwestern regions. The decreasing trend of gardens, parks and urban green space is still observed. This process is more intense in the case of parks and they will be destroyed more quickly. The reason for this is besides drought and withering of trees due to climate change, pollution, and conversion of these green land uses to rain fed agriculture, parks, poor rangelands and urban areas. As for the urban green spaces, the 16 and 4 regions have the worst positions, and the 17, 19. 2, 5 and 22 regions will not be safe from this damage either. The decrease in the area of rangelands and cities moved to new areas will increase; the cycle of destruction of vegetation will increase from the outskirts of Tehran.Conclusion: Construction was more in the south of Tehran and the decreasing trend of urban green space will continue to be observed. The central areas of Tehran will be completely devoid of trees due to the predominance of the urban areas, and the point to consider is the destruction of the green belt in the north of Tehran in the future.
Majid Homami; Seyed Ahmad Mirbagheri; Seyed Mehdi Borghei; Madjid Abbaspour
Volume 15, Issue 3 , October 2017, , Pages 153-172
Abstract
Introduction:
Rivers are among the major water resources and important and vulnerable inland ecosystems (Hayatolgheib et al., 2016). Today, the quality of such water resources has been threatened due to the irregular consumption of water and pollution of rivers by unnatural and human resources (Li et ...
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Introduction:
Rivers are among the major water resources and important and vulnerable inland ecosystems (Hayatolgheib et al., 2016). Today, the quality of such water resources has been threatened due to the irregular consumption of water and pollution of rivers by unnatural and human resources (Li et al., 2009). The Peer-bazar River and Anzali International Wetland has been subjected to severe eutrophication over the past two decades (Zebardast and Jafari, 2014). As a reuslt evaluation and estimation of changes in water quality the mouth area of the main feeding river estuary in the Anzali wetland (the Peer-bazar River) is in the first priority.
Materials and methods:
The present study aimed at evaluating the eutrophication status and prediction of temporal-spatial changes in nutrients concentrations, such as ammonium-nitrogen (N-NH3), nitrate (N-NO3), total nitrogen (TN), phosphorous (PO4-3), TP, in the estuary of Pir-Bazar river as the main and most important stream feeding the Anzali International Wetland. Sampling was performed from 10 points of the drainage basin within 18 months from December 2014 to June 2016. In this research, zoning maps were prepared and the status of present and future water quality parameters of the basin were accurately estimated using a researchers software-developed application and the five interpolation methods of Kriging, S-PLUS, polynomial regression, inverse distance to power, and local polynomial; and finally the optimal method was selected through a root-mean-square error (RMSE) based cross validation approach.
Result and discussion:
The results showed that in this drainage basin, the second order quadratic polynomial regression (with a mean RMSE of 0.2075 for TN and of 0.1475 for TP) and the topical polynomial with power of 10 (order of 3) (with a mean RMSE of 0.331 for TN and of 0.22 for TP) were the best and the worst methods for estimation of nitrate and phosphate levels in the drainage basin, respectively, as compared to other methods. In order to prepare the zoning map, monthly and seasonal maps of spatial distribution of nitrate and phosphate concentrations were created, and temporal (seasonal) changes in nutrients at the wetland entrance (estuary of Pir-Bazar river) were expressed. The results showed that the mean levels of nutrients in Pir-Bazar river water (0.616 mg/L for TN and 0.325 mg/L for TP) were higher than the allowed limits, according to the European directive 80/778/EEC and the OECD standard, (in normal conditions, the limits are 0.1-0.5 mg/L for TN and 0.01-0.1 mg/L for TP in fresh water). Also, according to the results of software, the mean TN to TP ratio at the wetland entrance was maximally 33.7 that exceeded the limit of 16. Therefore, the region’s water is subject to an advanced and critical eutrophication. Considering the positive and high values of the coefficient of performance for TP and TN between 0.87 and 0.918 (mean 0.894), it can be argued that phosphorus and nitrogen in this water basin are likely to share the same source; meanwhile the coefficient of performance varied between 0.187 and 0.721, showing the best performance for nitrate and phosphate, respectively.
Conclusion:
The results predicted by this software show that the mean annual concentration of ammonium, nitrate, nitrite, phosphate, and dissolved salts in this river will increase about 1.2%, 3.2%, 32%, 5%, and 7%, compared to the current situation in 2020. These figures will be about 3.4%, 9%, 87%, 14%, and 16.5% in 2030; this is a new finding and a reliable innovation in water quality management in the wetland.
