Saman Javanroodi; Mohammad Mahdavi; Baharak Motamedvaziri
Abstract
In order to determine the role of hydrological statistic data periods on flood forecasting in Sefidrood Watershed, maximum daily flows were collected from hydrometric stations, thus seventeen valid stations with long-term statistical data period was chosen and in some cases which data were corrupted, ...
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In order to determine the role of hydrological statistic data periods on flood forecasting in Sefidrood Watershed, maximum daily flows were collected from hydrometric stations, thus seventeen valid stations with long-term statistical data period was chosen and in some cases which data were corrupted, data has been reproduced by considering common time base.. At the second step, maximum daily flow data have been divided in to statistic series with 10, 15, 20, 25, 30 and more than 30 years data periods. Fitting statistic distribution of Normal, Normal log, Normal log 2 parameters, Normal log 3 parameters, Pearson log 2, Pearson log 3 and Gamble were determined by “Smada” software, also flood with two, three, five, 10, 25, 50, 100 and 200 return periods were calculated either. Statistic distribution for all of seventeen hydrometric stations were determined separately with RMSE method in Excel and SPSS for maximum daily flow.. Regarding zero-error in forecasted floods for long statistic data period (more than 30 years) in related return periods, compared with short statistic data period (10, 15, 20, 25 and 30 years), flood’s estimated error was calculated for all stations. In general, results indicated that increasing of statistic period, will enhance the accuracy of forecasting in hydrometric stations, and applying short-term data period will result in high levels of error.
Aboalhasan Fathabadi; Hamed Rouhani; Seyed Morteza Seyedian; Mohammad Mahdvi
Abstract
When watershed input, evatransporation and ground water usage be limitated, recession curve showed storage–output relationship for basin. This relationship can help us in low flow forecasting, decision and management of water resources; hydrological models calibration and etc. In this study recession ...
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When watershed input, evatransporation and ground water usage be limitated, recession curve showed storage–output relationship for basin. This relationship can help us in low flow forecasting, decision and management of water resources; hydrological models calibration and etc. In this study recession curve were modelled in Taleghan, Jajrod and Khoramdare rivers. At the first by consideration of annul hydrographs, recession lamb were separated then by doing some pre-processing recession curve get prepared for fitting various models. For each recession eight models were fitted. Result showed that for Jajrod and Talaghan, Barnes, Drogue, Coutagne and Wittenberg had better application, respectively. For Khoramdare river Horton, Barnes and Drogue had better performance with compared to others models. For Barnes model average value of K coefficient for Jajrod 0.97, 0.975 and 0.99, for Taleghan 0.967, 0.974 and 0.987 and for Khoramdare river 0.931, 0.945, 0.972 were obtained.
Seyedeh Maryam Alibakhshi; Mohammad Mahdavi; Shahram Khalighi Sikaroudi
Volume 2, Issue 2 , July 2010, , Pages 102-110
Abstract
Approximation of precipitation and design of a rain-gauge system with minimum initial cost and robustness against measurement uncertainties requires finding the relationship between various stations equipped with udometers .On the other hand, in areas where the issues of erosion and sediment exist, it ...
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Approximation of precipitation and design of a rain-gauge system with minimum initial cost and robustness against measurement uncertainties requires finding the relationship between various stations equipped with udometers .On the other hand, in areas where the issues of erosion and sediment exist, it seems necessary to know the amount of rainfall. Among the possible solutions, increasing the number of rain gauges can be adopted which is expensive. In the present study, rainfall data of 16 base stations by Ministry of Power recording precipitation data of Tehran Province on a common date (1622 rainfalls) were extracted. In each measurement, a station was chosen as base, the rainfalls of other stations were ignored, so the rainfall of each of them were reconstructed according to base stations, which were finally compared with observed rainfalls. Then, the curve of reconstructed and observed rainfalls was transformed into a dimensionless form, and rainfall percentage in the three quarterlies and the surface under each curve were calculated. Eventually by figuring out the error percentage of them, the frequency of error percentage in anticipating the rainfall amount and the three quarterlies for both curves were calculated. In order to determine the ratio of sensitivity of the model, distance index with statistical estimation of percentage of variation coefficient was used. Results demonstrated that there is no elevation effect within the 900 to 1800 m from sea level, but, there is a jump in the amount of error that this situation reduces gradually up to 2000 m height.
Hossein Saadati; Foroud Sharifi; Mohammad Mahdavi; Hassan Ahmadi; Mohsen Mohseni Saravi
Volume 2, Issue 1 , May 2010, , Pages 56-64
Abstract
In this study, rainfall, runoff, groundwater and unsaturated water tracers sample were measured and analyzed. The average historical recharge through rainfall was calculated by interpreting of unsaturated water tracer in Hasthgerd plain. Four index profiles in Nazarabad, Jafarabad, Ghalechendar and Savojbolaq ...
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In this study, rainfall, runoff, groundwater and unsaturated water tracers sample were measured and analyzed. The average historical recharge through rainfall was calculated by interpreting of unsaturated water tracer in Hasthgerd plain. Four index profiles in Nazarabad, Jafarabad, Ghalechendar and Savojbolaq were dug for measuring of unsaturated water tracer concentration. Chloride concentrations in profiles soil samples were measured and interpreted to provide temporal estimates of recharge. Applying the chloride mass balance technique to the profiles soil water improved the boundary conditions associated with wet and dry climate in last times and the long-term mean recharge rate. Recharge rate means were estimated in profiles equal to 3.42, 3.53 6.42 and 7.44 (mm/yr) with rainfall chloride concentration average that was measured equal to 1.653 mm in Hashtgerd Plain. It was concluded that concentrated recharge (CR) supplies groundwater rapidly and significant more than diffused recharge (DR) by rainfall. Concentrated recharge is fulfilled by watershed grand works such as flood spreading structural measures.
Seyed Hamid Reza Sadeghi; Seyedeh Laleh Razavi; Mohammad Mahdavi
Volume 1, Issue 2 , July 2009, , Pages 78-86
Abstract
Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role ...
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Many different runoff prediction methods are being used among which SCS model has been applied throughout the globe. It is therefore very important to evaluate the circumstances and input specifications under which such models could be applied. The present study was conducted to investigate the role of rainfall main characteristics on accuracy of SCS model in runoff prediction for Kasilian and Darjazin watersheds. For this purpose, the simultaneous rainfall-runoff data were selected and the storm runoff was estimated using determining rainfall characteristic, providing Curve Number map and calibrating the model. In order to determine the effects of rainfall characteristics on model output, the standardized values of regression coefficient (β) of the best fitted multiple regression, developed between rainfall circumstances and maximum storage index coefficient, were determined. The results of the study showed the depth, maximum rainfall in concentration time, maximum 30 minutes intensity, 2nd quartile and 1st quartile have the highest rate of effectiveness on model output respectively.
Ali Abdi Nam; Mohammad Mahdavi
Volume 1, Issue 1 , May 2009, , Pages 9-20
Abstract
Existing coarse materials produced during surface erosion in the marl watershed basins in tributary beds and impermeable subsurface layers (marl layers) lead to produce a subsurface flow. This subsurface flow can be used in order to develop vegetation cover in order to make the biological stabilization ...
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Existing coarse materials produced during surface erosion in the marl watershed basins in tributary beds and impermeable subsurface layers (marl layers) lead to produce a subsurface flow. This subsurface flow can be used in order to develop vegetation cover in order to make the biological stabilization of tributary beds. This method is very useful in the watersheds basins in which were performed the watershed practices such as Gabion dams and sediment ponds. This paper was the result of the research plan, which was considered as development of vegetation cover to biologically stabilize the tributary beds in Sardehat village areas as a split plot factorial statistical design. The three kinds of trees including: Almond, Elaeagnus, and Acacia as the main treatments, and the mixed of soil with manure and clay, and natural soil as the sub-treatments in three replications were studied in the selected area. During the performance of this study variables like stump diameter, height growth, and canopy cover were measured. Final results showed that considering the planting pattern Almond, Acacia and Elaegnus, and without considering the planting pattern Elaeagnus, Acacia, and Almond were preferred respectively in order to stabilize biologically the marl tributary beds.
