touraj sabzevari; Ali Talebi
Abstract
In many civil engineering projects such as urbanization, road and dam construction, before designing and operating, the subject of landslide of the hillslopes, especially in the conditions of high rainfall, which may have financial and human damages, should be considered. TOPMODEL is a subsurface model ...
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In many civil engineering projects such as urbanization, road and dam construction, before designing and operating, the subject of landslide of the hillslopes, especially in the conditions of high rainfall, which may have financial and human damages, should be considered. TOPMODEL is a subsurface model used to estimate surface and subsurface runoff of watersheds based on the Dunny-Block mechanism. This model is capable of detecting catchment saturation area and estimating the soil moisture deficit (SMD) across catchment. There is a relation between the hillslope saturation index, which is a key parameter in landslide models, and SMD. In this study, the relationship between the two models of SINMAP (landslide model) and TOPMODEL and their parameters have been studied. For this purpose, the data of the ILAM Dam catchment data located in the southeastern province of ILAM in IRAN was used. The ten hillslopes of the area were taken to calculate the sliding. Using GIS, maps of SMD and index of saturation were calculated based on TOPMODEL, and finally, stability maps of SINMAP were calculated for the region. Hillslopes 3, 4, and 5 are quasi-stable according to the model, stability probability is less than 50% and stability probability is more than 50%, and in nature these hillslopes are unstable. The 8, 9, and 10 hillslopes that are used in nature from the vegetation of oak trees are stable, according to the model of these three hillslopes.
Touraj Sabzevari; Mehdi Karami Moghadam
Abstract
Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, ...
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Time-area hydrograph and Clark’s methods are commonly used for prediction of runoff in catchments. In the both methods, the Time-Area Diagram (TAD) of the catchment is needed. In this study, two methods for estimation of Dimensionless Time-Area Diagram (DTAD) are introduced. In the first method, called geometric method, a hyperbolic function for the geometry of the catchment is assumed. Furthermore, travel time is assumed to be proportional to an exponent ( ) of flow distance to outlet. It was shown that the resultant DTAD equation is equal to USACE (1990) equation when is one. In another method, called Nash-TA, DTAD equation was derived as a function of Nash model parameters. The two developed methods were applied to Ajay catchment, in India, and Kasilian, Jafarabad, Shourandika catchments, located in Iran, and the results were compared to those obtained from the kinematic wave method. The efficiency coefficients for geometric method with being 0.6 and for the Nash-TA method were 0.971 and 0.955, respectively. The efficiency coefficient for geometric method in cases of =1, 1.5, 1.67 were 0.824, 0.484 and 0.161, respectively. The efficiency of the geometric method ( =0.6) and the Nash-TA method was satisfactory.
Touraj Sabzevari; Mehdi Mokhberi; Sadegh Hosseini khotbehsara
Abstract
Catchments consist of a series of sloping pervious overland whose surface and subsurface runoffs are transmitted to their outlet through stream networks. In the catchments with high perviousness and good vegetation cover, the amount of subsurface gains more significance and it might have a considerable ...
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Catchments consist of a series of sloping pervious overland whose surface and subsurface runoffs are transmitted to their outlet through stream networks. In the catchments with high perviousness and good vegetation cover, the amount of subsurface gains more significance and it might have a considerable share in the direct runoff. In this study, a hydrologic rainfall simulator model with the length of 1.92 meter and width of one meter and depth of 0.35 meter has been used which its surface and subsurface amount of flow have been measured by means of two different weirs. The texture of soil in Estahban Watershed was loamy sand. The experiments were conducted under three slope angles of 0.1, 3, 6 and 9 degrees and under rainfall intensity of 31.73, 47.6 and 63.46 millimeter per hours. Based on the results, the slope changes from 0.1 to 3 degrees resulted in 50 percent decrease in the subsurface flow and 10 to 15 percent increase in the surface flow in different rainfalls, but, from the slope of 3 to 9 degrees, no significant change was observed in the two flows and in the slope change from 6 to 9 percent of subsurface flow and 2 percent of surface flow, there was surface flow observed. The increase in rainfall intensity causes rise in hydrograph amount of surface and subsurface flow. The proportion of surface to subsurface flow changed on average between 7.5 and 14.5 times the subsurface flow under three rainfalls for the loamy sand. With the increase in slope, the surface flow amount increases and infiltration decreases. In this study, two non-linear regression equations were presented for measuring surface and subsurface peaks which is a function of length, slope and rainfall intensity of the slope.
