تحليل فراواني منطقه اي خشكسالي هيدرولوژيك با استفاده از شاخص خشكسالي جريان سطحي ( SDI﴾ ﴿مطالعه موردي حوزه كارون شمالي﴾

چكيده انگليسي :

Regional frequency analysis of hydrological drought using stearmflow drought index Northern Karoon Watershed Maryam salahshour m2007 iut@yahoo com 23january 2013 Department of Natural Resources IsfahanUniversity of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Saeid Soltani ssoltani@cc iut ac ir Abstract Drought as an unavoidable phenomenon and natural catastrophe has been occurring in different zones of countries especially those located in arid and semiarid regions frequently In recent years this phenomenon has been becoming more acute and caused too many causalities and damages Drought predictions serve as the most important combat and reduce drought damages Recently to calculate and evaluate streamflow drought index SDI has been received too many attention as one of the hydrological drought prediction approach In frequency analysis of this index we are encounterinto short term statistical period and basins without measurement stations which to overcome them the frequency analysis regionalization method is used On the other hand since droughts occur as regional in vast area for long term periods to study them in regional concept is important In the present research we exploited frequencyregional analysisof streamflow drought indexto predict hydrological drought in northKaroon basin For this weselected the number of fourteen appropriate stations and collected their statistics Since one of these stations had less recorded data and due to short statistical period we eliminated this stationand conducted regional analysis with other ones To investigate homogeneity of study area weconsidered and climatic physiographical features of elite stations and to carryout homogeneity test we used Husking and Wallis 1991 and cluster analysis Results of cluster analysis showedthat study area might be consideredas ahydrological homogenous region Then in respect to availablestations discharges and SDI calculation formula we calculated this index value in time series of 3 6 9 and 12 months Basedon Chi square goodness of fit test and kolomogrophSmirnoff three parametric distributions was identified as a best regional distribution Accordingly SDI index of 3 6 9 and 12 months with return periods of 2 5 10 50 and 100 years using FERQ program in every station To conduct regionalfrequency analysis and relationship between differentparameters and SDI values with different return periods multivariate regression was used and as a whole the number of thirteen climatic and physiographic features was applied to prepare regional models Results of regional analysis indicatedthat area concentration time main waterway length main waterway slope Miller coefficient and Gravelious one are the effective factors on study area SDI index In terms of obtained results the region was classified in to slight moderate sever and very severedroughts and it was found that regionsamong Karoon basin northwest and north area experience much more drought than other ones So they are subject to hydrological drought eco social damages hence they must be given too much attention in water resources studies Keywords drought hydrological drought prediction surface flow drought index SDI northernKarron regional analysis

سلحشور دستگردي، مريم

تحليل فراواني منطقه اي خشكسالي هيدرولوژيك با استفاده از شاخص خشكسالي جريان سطحي ( SDI﴾ ﴿مطالعه موردي حوزه كارون شمالي﴾

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