Showing 5 results for Hashemy
M. Nourzadeh, S. M. Hashemy, M. J. Malakouti,
Volume 15, Issue 57 (fall 2011)
Abstract
Electrical conductivity and acidity of soil are the most important chemical factors of soil for agriculture. The nature of soil is in such a way that its change has a continuous form. The method that can take into account this continuity will be able to show a better picture of change in soil characteristics. Objectives of this research are to investigate the relations between measured electrical conductivity and soil acidity of Qom plain, and clustering, compare the clustering methods, determine the optimum numbers of cluster, and to zone the clusters in the study area. Accordingly, two fuzzy clustering methods FCM and GK, were used for data mining and clustering of 465 measured data. For estimating the appropriateness and comparison of two methods, some criteria including Partition Coefficient, Classification Entropy, Partition Index, Separation Index and Xie and Beni's Index were used. Data mining results showed that the optimum number of clusters for FCM and GK method was 15 and 17, respectively. After investigating the results of clustering and based on the criteria of appropriateness, it was indicated that GK was the best clustering method. According to this method, 295 data from 465 measured samples had more than 40 percent of membership function. So, 9 clusters from 17 clusters had more than 20 members. Then salinity-alkalinity zoning based on GK method to show the clusters distribution better in the study area was prepared. This prepared fuzzy map explained that most of Northwest and west belonged to cluster 1 and eastern parts of study area include belonged to cluster 17. Based on this, salinity-alkalinity and the ensuing soil degradation in east of study area is more likely than the west of it.
S. Barkhordari, M. Hashemy Shahdany, A. Bagherzadeh Khalkhali,
Volume 23, Issue 3 (Fall 2019)
Abstract
Seepage losses and poor operational activities are the two main source of water losses throughout the agricultural water conveyance and distribution systems in irrigation districts. This study aims to investigate the performances of two strategies of “canal lining” and employing the “Canal Automation” in order to reduce the losses mentioned above. The investigation was carried out on a couple of main canal reaches of Moghan Irrigation Districts. Two numerical models were simulated by Seep/w software to compare the seepage rate between the canal with and without concrete lining. The results reveal that the ability of concrete lining to reduce seepage losses along the canal is about 10%. Performance assessment of the “Canal Automation” strategy to minimize operational losses within the main canal was carried out employing Model Predictive Control (MPC). The results of the latter strategy indicate that employing the MPC not only reduces the operational losses along the canal by 15% but also improves the operation of the main canal so that the minimum efficiency and adequacy performance indicator was obtained 100% and 83% respectively. Therefore; due to Executive considerations and financial constraints in the same cases, the potential of each of the two strategies can be considered to reduce the conveyance and distribution losses and ultimately choose the most suitable option.
Y. Hassani, S. M. Hashemy Shahdany, B. Zahraei,
Volume 24, Issue 1 (Spring 2020)
Abstract
This study focused on proposing a new operational perspective within main and lateral irrigation canals based on the economic value of water. To achieve this objective, the operation-economic framework offered in this study consisted of two main components of the PMP model and Operation model. The estimated economic values of water in different regions of the network were employed as the starting point for connecting the economic model with the operation model. It is worth mentioning that the technical perspective targeting adequacy of water distribution within the canals was modified in this study to be applied for the operation-economic framework since the original forms of the indicator were based on physical inherent of the water. Roodasht Irrigation District, located at Zayandeh-Rud basin, was selected as the case study, and the proposed framework was tested on the district. The obtained results revealed that in response to implementing the proposed framework in water distribution within the canal under the water shortage condition, alfalfa and safflower were the two crops those cultivation was decreased drastically in comparison with the other crops. The primary reason for the decrease was the lower values of the economic value of water for these two crops. Also ,the results of the canal operation appraisal from the adequacy of water delivery revealed that for the traditional operating system (without considering the economic perspective), the maximum values of the adequacy indicator were obtained for the upstream four canal reaches. On the other hand, the off-takes numbers of 1, 6, 5, and 12 got the maximum values of the adequacy indicator when the proposed operation-economic framework was applied for the canal system.
A. Kaghazchi, S. M. Hashemy Shahdany, A. Roozbahany, M. E. Banihabib,
Volume 24, Issue 3 (Fall 2020)
Abstract
The main purpose of the study is the operational simulation of main irrigation canal and evaluation of water delivery and distribution locally, regionally and overall using adequacy, efficiency, and equity indicators and “Desirability of water delivery and distribution” indicator. To achieve this goal, the hydrodynamic model of Roodasht irrigation network’s main canal was developed. The results of the calibration and validation of the hydrodynamic model showed that the two processes were satisfactory. All available scenarios including normal, water shortages and fluctuations were considered for water delivery and distribution in different conditions. In the local assessment, the adequacy varied from 7 to 85%, and the efficiency in all scenarios was 100%. The adequacy, efficiency, and equity indicators in the regional evaluation varied from 6 to 89, 91 to 100, and 13 to 46%, respectively. The overall evaluation of the canal showed that the most desirable situation is related to a harsh fluctuation increasing with the adequacy, equity and efficiency indicators equal to 82, 23 and 91%, respectively. Calculation of the “Desirability of water delivery and distribution” indicator showed poor performance in all operational scenarios except harsh fluctuation scenario with 82% of which, the canal performance was estimated in fair level.
M. Mehri, M. Hashemy, S. Javadi, M. Movahedinia,
Volume 27, Issue 3 (Fall 2023)
Abstract
Rapid urbanization is responsible for impervious area increases and more runoff generation in urbanized catchments. Higher runoff volume in urbanized catchments leads to higher flood risk. One of the methods of runoff management is low impact development (LID). Bio-retention cell (BRC) is one of the infiltration-based LID practices that allows restoring the pre-development hydrologic cycle. However, the overall hydrologic performance of BRCs can vary depending on different urban environments. In this study, the hydrologic performance of BRC in terms of runoff and flood reduction was investigated in a highly urbanized area in the east of Tehran, Iran. The SWMM model was used to evaluate the performance of BRC. The results showed that BRC for rainfall with a return period of 2 to 50 years reduced the total runoff volume by 76.2% to 70.2% and the peak discharge by 65.9% to 36.4%, respectively. Also, for rainfall with a return period of 2 to 50 years, BRC resulted in 15.2% to 27.5% infiltration of rainfall in the study area, respectively. This study demonstrates that BRC can help restore the natural hydrologic cycle of urbanized catchments by reducing runoff and increasing infiltration.
