hydrogeology
Fariba Esfandyari Darabad; Zeinab Pourganji; Raoof Mostafazadeh; Maryam Aghaie
Abstract
Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior ...
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Floods as destructive natural hazards need to be predicted in accurate way through evaluation of the hydrological response of watersheds to the effective input rainfall. Due to the variety of rainfall-runoff models, it is very important to choose a suitable model that can simulate the hydrological behavior of the watershed. In this study, various rainfall-runoff transformation methods have been evaluated, including triangular, broken triangular, variable triangular and SCS-curvilinear unit hydrograph methods in Nenekaran watershed, Ardabil province. In this regard, the Wildcat5 hydrological model have been used to this purpose. The precipitation amount at the 25-year return period was calculated using Cumfreq software. After preparing the land use map of the study area using satellite images, the area of each land use in the area has been calculated using ArcGIS software. The precipitation value and the time of concentration were considered constant during the simulation procedure. The results showed that the SCS method had the highest runoff of 44.50 cubic meters per second. The minimum time to the peak was 2.19 hours and the variable triangular method had the lowest peak flow rate. The simple triangular method has a maximum time to peak of 4.51 hours, which shows the great difference between the hydrograph of the SCS method and the other three methods. The difference in the nature of the methods, the watershed condition, and the suitability of estimating tc and CN parameters should be considered in rainfall-runoff transformation methods.
Hassan Khavarian; Maryam Aghaie; Raoof Mostafazadeh
Abstract
1-IntroductionLand use change has significant effects on hydrological and ecological processes at different temporal and spatial scales. Many hydrological models have been developed based on the characteristics of the basin, available data and purpose of the study. To predict the characteristics of river ...
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1-IntroductionLand use change has significant effects on hydrological and ecological processes at different temporal and spatial scales. Many hydrological models have been developed based on the characteristics of the basin, available data and purpose of the study. To predict the characteristics of river flow, we need to develop the rainfall-runoff model to predict the flow for a long period of time. This study has been carried out for the modeling of monthly runoff using Temez model and then the effects of the different land use change scenarios on runoff components have been assessed.2-MethodologyIn this study the OLI-Landsat 8 satellite imageries, a digital elevation model (DEM) as well as meteorological and hydrological data were used for the modelling purpose. The land use classification was carried out using a support vector machine (SVM) method to create a map with 6 land use classes: dry farming, forest land, water body, pasture, built-up and irrigated agriculture. Then, the 10 management scenarios have been developed based on the field observations and taking into account the field characteristics, changes trend in the land use pattern, and the suitability of the study area for different land uses. In order to simulate the runoff, the Temez monthly hydrological model was employed. A 10-year (2002 to 2012) daily precipitation, temperature and runoff data were aggregated to monthly time scales. The calibration and validation steps were performed based on observed data. For calibration of the model, the first 6 years data and for model validation 4 years data were used. The parameters of the Temez model were calibrated based on the values obtained from the literature. First, the appropriate coefficients were found for each land use in the watershed and then the area of land uses in all scenarios were computed. Finally, the weighted average was calculated for the coefficients and appointment in Temez model. 3-Results and DiscussionThe accuracy of the land use map was quite high. A Kappa coefficient of 0.95 and an overall accuracy of 0.975 was obtained. The accuracy of the modeled runoff was presented using R2 coefficient, which was 0.77 and 0.65, for calibration and validation stages, respectively. The results of considering the land use change scenarios on the monthly runoff showed that land use reclamation scenarios of 3, 4 and 5 had a decreasing effect on the runoff by 3.4, 3.3, and 4.1 percent, respectively. Also the land use scenarios of degradation condition, 9 and 10 scenarios, caused an increasing effect on the monthly runoff to 15.24 and 4.5 percent, respectively.4- ConclusionThe monthly hydrological Temez model showed relatively good performance in estimating monthly runoff values based on the data used. The results can be considered in predicting the development and degradation conditions in the study area. Keywords: Land Reclamation, Land Degradation, Kouzehtopraghi Watershed, Land use Change Scenario, Monthly Runoff Feature, Temez Model5-ReferencesArceo, M.G.A.S., Cruz, R.V.O., TiburanJr, C.L., & Balatibat, J.B (2018). Modelling the hydrologic responses to land cover and climate changes of selected watershed in the Philippines using soil and water assessment tool (SWAT) model, DLSU Business & Economics Review, 28, 84-101.Andrade Abe, C., Lucialobo, F.O., Berhan Dibike, Y., Farias Costa, M.P.D., Dos Santos, V., & L.M Novo, E.M (2019). Modelling the effects of historical and future land cover changes on the hydrology of an Amazonian basin, Water, 10(932), 1-19.Feki, M. R., G. Gepple, A. Mille, G. Mancini, M (2018), Impact of infiltration process modelling on soil moisture content simulations for irrigation management, Water, 10(850), 1-20.Garg, V., Nikam, B.R., Thakur, P.K., Aggarwal, S.P., Gupta, P.K., & Srivastav, S.K. (2019). Human-induced land use land cover change and its impact on hydrology, HydroResearch, 1, 48-56.Gumindoga, W., Rwasoka, D.T., Ncube, N., Kaseke, E., & Dube, T (2018). Effect of land cover/land-use changes on water availability in around Ruti dam in Nyazvidzi catchment, Zimbabwe, Water, 44(1), 136-145.Hyandye, C.B. Worqul, A., Martz, L.W., & Muzuka, A.N.N. (2018). The impact of future climate and land use/cover change on water resources in the Ndembera watershed and their mitigation and adaptation strategies, Environmental System Research, 7(7), 1-24.Jain, S.K. (1993). Calibration of conceptual models for rainfall-runoff simulation, Hydrological Sciences Journal, 38(5), 431-441.Onate-Valdivieso, F., Bosque-Sendra, J., Sastre-Merline, A., & Ponce, V.M. (2016). Calibration, validation and evaluation of a lumped hydrologic model in a montain area in Southern Ecuador, Agrociencia, 50(8), 945-963.Temez, J.R (1977(. Modelo matematico de transformacion. Precipitacion. Aportacion. Asociacion de Investigacion Industrial Electrica ASINEL, 1-10.
