Water Balance Model for Highlands of Anzali Wetland Basin by Using GIS

The atmospheric precipitation through and evaporation of water from surface waters of oceans, seas, lakes, and other water bodies are in balance through... Can be,  Hhydrological cycle is a balance mode. Regional Oobservations indicate of that rainfall in the regional says that rainfall changes in various years, Furthermoreconsequently, the rainfall becomes runoff, which can also be variable.  
    The aim of this research, was to study and analyzesis of the Anzali Wetland basin water balance in the height highlands of the mountains, where there being a lack of hydrometric stations are lacknig in some watersheds. Therefore, using empirical models (S.C.S) were used to evaluate water resources has been throughand gather the necessary knowledge concerning surplus water resources of the area and find out whether there is surplus or shortage of wateror maybe it should be the shortage.
    In this study, using digital topographical maps (for purvey digital elevation model), soil maps, and data from the meteorological station within the basin and some neighboring ofstations on that neighbor confine within the layer of precipitation, evaporation, and infiltration of  rainwater into the soil, for the region with the raster data layers were obtained. And theBy overlaying of this information in the GIS software, Wwater balance in the distribution of wetland elevations basin highlandsover a period of 25 years, were reviewed and analyzed over a period of 25 years.
    For determining the water balance, wWater balance status of the individual parameters effluence affecting balance equation in this study are based on and included precipitation, evapotranspiration, and surface water runoff and will bewere studied within. After investigation and determination of these parameters, the information was used in the GIS environment, as GIS data layers. becomes , In this form, tThe structure of this region consisted ofas well as similar cells and haswith little value todependence on information is the information layer. Then, using the SCS method, runoff is was measured in the study area. Curve Number (or CN, where the) maps, of obtained from land combining land maps with hydrologic soil groups, and were used can be for Mmapping the water retention coefficient. (S) In addition, was side other hand with using data of the local meteorological stations, the trend in rainfall and evapotranspiration was analyzed over a period of 25 years was prepared.








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     The results of this study indicated that the average annual total volume of the inputinflow in over the 1789.8  km² area of the basin, during the 25-year period were was 25 times 2319.2 million cubic meters, while the annual output outflow stream (Total i.e. evapotranspiration and plus runoff,) was equal to 3397.5 million cubic meters, indicating a negative trend is that in some areas of the southern highlands of the basin, a trend has been negative.