جستجوی مقالات مرتبط با کلیدواژه « experimental methods » در نشریات گروه « جغرافیا »

Knowing the maximum flow rate is necessary to deal with floods, and one of the main problems in watershed planning is the lack or absence of necessary statistics, especially hydrological statistics. Therefore, the absence or lack of hydrometric information in watersheds requires appropriate experimental methods to estimate the maximum discharge. Thus, this research aims to estimate the maximum discharge in the mountainous part of Qaranqoo Chay and analyze the hydrological changes of the river. This research relies on fieldwork, using satellite images and topographic and geological maps. In this research, the water velocity was first measured using the Costa and Jarrett method, and then the flood discharge was estimated based on that. The hydrological conditions of the river were also calculated according to the data of the upstream and downstream stations of the range and using 18 indicators. The research results show that the maximum flood estimated by the Costa method (89.60 m3/s) is closer to the observed values, which indicates the efficiency of this method. Based on the research findings, the connection of Saraskandchay, Shorchay, and Khatonabadchay branches, high slope and impervious formations, low cross-section and channelization of the flow, local blockage due to the fall of large stone fragments and the filling of the section can be considered as the reason for the high maximum flood values in the mountainous part of Qaranqoo Chay. In addition, the results of the study showed that the construction of the Sahand dam caused a fundamental change in the downstream flow regime, and these changes affected the hydrological characteristics.

Tighab catchment has located between Khash and Iranshahr Townships. In this survey after collecting long time temperature, discharge and precipitation statistics (22 years) for catchment, we carried the research in two parts. The first section has been allocated for evaluating different methods for estimation of annual discharge of catchment and the second one for evaluating flood-water and selecting the best and the most appropriate methodology to estimate its value. Different statistical tests have been done on the data to ensure data homogeneity and distribution of selected stations, Using Justin, Indian Committee Agriculture (ICAR), Institute Irrigation Investigation up state of Indian and Lisi methods, the height of annual run-off has been calculated and the best method for estimating annual discharge was selected. Therefore, among used methods, Justin method gave better results because of considering more climatic and non-climatic parameters and regional coefficients for estimation of annual discharge. It is thereby suggested to be used in the Tighab catchment. At the next step, the regional flood-water has been studied and after estimating flood-water discharge in station, and investigating of different methods of flood estimation and selecting the most appropriate method at different return periods was also done. According to observed results, in order to obtain maximum floodwater momentary discharge, the SCS method shows more generality. In this study, since there is a serious limitation of ground water in Tighab region and so with the purpose of collecting and haltering surface and groundwaters, the attempt was focused on estimating both the value of annual discharge and the sub-basin flood-water of the study region.