jamal mosaffaie; mohammad reza ekhtesasi; Amin Saleh pourjam
Abstract
Study of geological units is one of the basic studies in many different sciences such as natural resources. The use of geological maps produced by geological survey is now the basic of geological studies in detailed-operating and investigative studies of natural resources. On the other hand, during the ...
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Study of geological units is one of the basic studies in many different sciences such as natural resources. The use of geological maps produced by geological survey is now the basic of geological studies in detailed-operating and investigative studies of natural resources. On the other hand, during the last years, remote sensing technology has been introduced as a new and efficient tool for geological studies that in addition to proper precision, it has other benefits such as accessibility to impassable or inaccessible mountainous regions. In this study, comparing the accuracy of existing geological and remote sensing maps of Vartavan catchment of Qazvin province has been the object of the study which was evaluated with the ground realities. So first, maps of geological survey were examined. Then, various image processing techniques including False Color Composite (FCC), Principal Component Analysis (PCA), Optimum Index Factor (OIF) and Band Ratio (BR) were used to enhance different lithological units and finally, RS lithology map of the catchment was prepared. Considering the variety of rocks and formations of the study area, the FCC and OIF techniques have respectively the most capabilities for differentiation of the rocks. Kappa coefficient of 0.39 between the two maps indicates low agreement between them. Checking the accuracy of maps based on the ground realities showed that photo-lithological map is more accurate (97.1%) compared to geological map (52.5%).
Jamal Mosaffaie; Davoud Akhzari; Saeed Rashvand; Javad Ataei
Abstract
One of the important parameters in the design of flood control structures is to determine flood peak discharge for various return periods. A primary issue of planners in the face with flood is lack of data or insufficient data. One of the most reliable strategies is generalizing the results from sites ...
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One of the important parameters in the design of flood control structures is to determine flood peak discharge for various return periods. A primary issue of planners in the face with flood is lack of data or insufficient data. One of the most reliable strategies is generalizing the results from sites with observed data to ungauged locations. The main goal of this study is regional flood frequency analysis using multiple regression method for Qazvin province of Iran. 8 out of 23 existing hydrometric station were removed because of the short-term statistics and construction of storage dam at upstream. The results of factor analysis showed that perimeter, equivalent diameter, time of concentration, length of main waterway and area were the main variables affecting flood magnitude. The remaining 15 stations were divided into two homogenous regions using cluster analysis. Homogeneity of these two regions was confirmed using homogeneity and heterogeneity tests of L-moments. Based on the best-fit criteria of Zdist, GNO distribution with the statistic of 0.29 has the best fit for the entire region but for one and two homogeneous regions, GLO and GPA distributions with the statistics equal to 0.09 & 1.56 have the best fit respectively. After calculating parameter values for selected distributions, discharges with different return periods were estimated for all stations. Then, regression relations were obtained between peak discharge and factors affecting flood peak for each return periods at two homogeneous regions. Peak discharges at ungauged locations can be estimated for different recurrence interval using these relationships.