Simulating Flood By Using Remote Sensing Data and Cellular Automata Model (Case Study : Talar River Basin-Iran) Azadeh Mousavi M.Sc. Remote Sensing Student Earth Science Department, Shahid Beheshti University, Tehran Iran Phone:0098-21-22445157 amousavi58@yahoo.com Abstract : Although creating new methods in water resources field is essential , So in this research haad tried to use cellular automata method as a simulation model for creating a new method in flood simulation . Flood simulating by this method can simulate flood quickly , precisely and by cost reducing . In this new method , by integrating remote sensing data form satellite image , using hydrological rain fall runoff model and cellular automata model , dispersion of flood had been determined. In this study for implementing model , flood simulator software has been developed. This software can simulate the flood dispersion by acquising it’s information from a database . Geometric and rainfall information of basin have been stored in this database. The model used for simulating the probable flood prone areas of Talar basin, which is basin in the north of Iran and the flooded maps are prepared. simulation resaults demonstrated that simulating flood by cellular automata model ,has conformity to reality. 1-Introduction: Inspite of various researches and developted methods about flood management ,creating new method which serve as a quick and precise methods in flood management field is essential. Flood simulation is one of this method. The goal of this paper is to simulate flood by integrating spatial simulating methods like C.A1 Model and Geographical information system and remote sensing by using Satellite images as a data source. In this paper, we developed a 2-dimensional Cellular Automata model to simulate the flood of Talar basin during a sudden rain fall. A Flood simulator software had been developed which simulated the spread of flood by getting the rain fall data of basin. In this way we can prepare the flood map of lands and different flooded features. In this research C.A method had been served for the first time in Iran basin . 2-Methodology Because createing flood simulation model by C.A is the most important aim of this research , So after designing flood dispersion model , for validating and calibrating created model we used the information of a natural flood. Golestan flood had been selected of this and we implemented the model based on the information of this flood . At first Developted simulating flood model was tested for Golestan flood and after comparing the resaults of model and natural flood and getting acceptable resault ,the model was implemented for probable flood of Talar basin. For simulating flood dispersion of river we used flood simulating software which had been developted base on C.A model .It need the geometric and rainfall information of basin for calculating the spread of flood. A database that desine in rational form supportes the software.This database have composed of the spatial and attribute information of elevation , rivers, rainfall , land use , land cover and vegetation of each sub basin of main basin. The needed map had been prepared in vector model and after changing to raster model had been stored in flood data base.All information which are useful for flood simulating get from database and after processing can store there. 2-1-Preparing land use from satellite image: For getting the information of land use in basin , the information of ASTER sensor had been used.The geometric and radiometric correction had been done on this images and by using the related algorithm , images classified and the vector map of basin land use prepared.(figure1)  Figure1:Aster image and land use map that prepared 2-2-Designing flood dispersion model by Cellular Automata Model For designing flood dispersion model hade been used C.A model. Cells,State,Neighbourhood and Taransition rules are four specific elemnts which should be regarded. In this model digital elevation model had been used as basic cellular network .When a sudden rain fall occure and runoff flows , the flood run off discharge for all cells and finally for river cells compute and flood height storied in database. Logical hydrological flood model has the essential role in this computation. The flood discharge for each river cell determine by adding the amount of the other discharge cells which flow to the river cells and the amount of basic discharge of river in ordinary situation .In follow this truth have shown.  Figure 2: It shows the direction of water flow in rivers with different QC = Q’ + ?QC’ QC :River discharge Q’ :Initial Or basic discharge ?QC’ :Total amount of other flood discharge cells When the amount of flood discharge determined for each river cells ,this water should be spread .River and non river areTow state which are in cellular network . For river cells the amount of water wich stores in cell is sum of Initial discharge ,rain discharge in duration of rain fall and flood runoff which flow form the neighbour cell, this amount for a non river cell is only sum of the water from neibours cells. Von neuman and more are two kind of neibourhood which celected for C.A model in flood simulation model. Transition rules which describe below are the rules that determine flood dispersion from each cells. Transition Rules for each Neighbour Cells That Sourrounded around Central Pixel are: If H(i’,j’)-(H(i’,j’)+hw((i’,j’)) > 0 then water flow would not occure If H(i’,j’)-(H(i’,j’)+hw(i’,j’)) < 0 then water flow would occure If H(i’,j’)-(H(i’,j’)+hw(i’,j’)) = 0 then water flow would not occure  Figure3:It shows the flood thspersion according to the transition rules In this model for each floody cells the amount of water height is part of central cells in aspecific neighbourhood and according to the transition rules. 2-3-Flood simulator software This software had been developed for simulating flood dispersion by C.Amodel. This program has simple user interface and can simulate the flood dispersion only by getting rainfall height . Flood simulator software had been writen by visual basic6 language .  Figure4:It shows th main window of flood simulator software 3-Resaults Comparing between the natural Golestan flood resaults and model resaults demonstrated that flood model had reliable resaults, and the corealation of data (0.86) admited this resaults. After getting good resaults from Golestan flood test and model validating ,the probable flood map of Talar river had been prepared that one of this map have shown in figure 5.  Figure5: Talar river flood map This map shows the features that covered by flood have been demonstrated  Figure6: Talar river flood map and flooded features This table shows the amount of features that flooded (recorded rain in october2002)
The flood model and flood simulator software which developted in this research can serve for preparing flood map of basins . Integrating the resaults of this research and he other data ources like meteorological satellite data which can forecast the situation of weather can serve in flood management and make people aware about the probable flood and probable damages. 5-References
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