Showing 4 results for Seepage
H. R. Salemi, A. R. Sepaskhah,
Volume 10, Issue 1 (4-2006)
Abstract
Estimation of seepage is essential prior to lining of earth canals. In Iran such investigation has been achieved in some irrigation networks using empirical relationships derived in other countries. Estimation of water loss in canal is required in design, operation and management of water distribution systems. Water seepage may be determind by using empirical equations proposed by F.A.O. These equations are applicable for different soils and hydraulic parameters. However, the appropriate estimating equation should be determined for each region. Therefore, these equations should be calibrated for local usage and different canal vegetation conditions. In this investigation water losses in canals at the Rudast region of Isfahan were measured by inflow and outflow procedure. Different canals reaches were selected in soils of relatively heavy, medium and light textures. The density of vegetation population in canals were low, medium and high. The estimated seepage losses by different empirical equations were not corresponded to those of measured values. Therefore, by using the measured seepage at different soil textures and vegetation densities the empirical coefficients of six empirical equations of F.A.O. (Ingham, Davis and Wilson, Affengendon, Moritz, Molesworth and Yennidumia, Misra) were modified for the study region. The relationships between measured seepage and estimated seepage before and after modification of the empirical equations were determined by regression analysis. These equations estimated the seepage loss much smaller than the measured values. The regression parameters (selope, intercept, and coefficient of determination of regression equation) indicated that after modification, the Ingham and moritz equation with higher slopes (0.91, 1.01), lower intercepts (-0.096, -0.039) and higher coefficient of determination (0.96) estimated the closest seepage values to the measured values respectively. The misra equation was the next best equation for seepage estimation. The results of present investigation indicated that the modified Ingham and Moritz equations were the most appropriate ones for estimation of seepage losses at different soil textures and vegetation densities in the study region.
R. Rostamian, J. Abedi Koupai,
Volume 15, Issue 58 (3-2012)
Abstract
To optimize the use of water for agriculture, knowledge of the seepage of the channel is required. Although there are many empirical equations for estimating canal seepage, the coefficients of these equations are different from Iranian conditions and these equations vary in different areas. In this research, the ability of the SEEP model was studied to estimate the seepage from earth canals in downstream of Zayandehrud dam. Seepage from seven different earth canals (degrees of 3 and 4) was simulated with the model of SEEP and the results were compared to the water balance studies. Also, four empirical equations, Davis-Wilson, Moles worth and Yenni dumia, Moritz and Ingham were used to estimate seepage from these canals. The determination coefficients for these methods and SEEP model were obtained 9.3%, 6.7%, 37.3%, 18.3% and 87.9%, respectively. In contrast with empirical models, SEEP model has a proper ability to simulate seepage from degree 3 canals. The empirical models must be calibrated for local conditions.
S. Barkhordari, M. Hashemy Shahdany, A. Bagherzadeh Khalkhali,
Volume 23, Issue 3 (12-2019)
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.
S. Salehi, A. Mahmoodi Moghadam,
Volume 27, Issue 2 (9-2023)
Abstract
The present study investigated the related parameters to decrease the seepage through homogenous and heterogeneous earth dams by employing experimental models and solutions. Two heterogeneous earth dam models with vertical clay cores were considered to illustrate the effect of the electrokinetic application on the time failure factor. The seepage lines were measured along the longitudinal section from the heel to the toe using the observation wells by adjusting the electrodes of the electrokinetic application through the vertical clay core. The initial comparison expounds that adjusting the electrokinetic approach can decrease the level of the seepage line due to depleting water by considering horizontal drainage. Furthermore, the failure time was increased by 18 percent due to inputting the voltage in the clay content. The results indicated that the models with an electrokinetic approach were stabilized more than the ones. The hydrographs of the flow discharge were measured along the experimental tests to investigate the effect of electrokinetics with and without electrodes in 10 and 20 clay percent of the dam soil content. Results indicated that employing the electrokinetic application due to increasing clay content caused the effect of the electrokinetic was significantly increased and it caused the discharge flow reduced of 32 percent.
