Abstract
Investigations were carried out to determine the dynamics of vegetation around the Ili river delta, an arid zone in Kazakstan, using 5 year chronological data of NOAA LAC satellite images obtained in summer. From necessity to take reflectances of background soils into account when estimating vegetation amount in arid zones, soil reflectances of the different soil types were measured from 22 points. TSAVI values from the soil lines were calculated to describe the properties of each of the soil types. Vegetation dynamics was then determined through regression analysis of chronological data of the generated LAI images of Ili delta. From the results, it was clarified that vegetation distribution along the Ili delta was affected by allocation and fluctuation of flow along Ili river branches but not by precipitation during the dry season. Wide differences were also observed in the response pattern of “precipitation dependent” and “river and underground water dependent” vegetation with respect to flow fluctuation along Ili river branches. It was confirmed that vegetation decline in Ili delta was caused by water diversion for large scale irrigation purposes, and decrement of flood frequency due to the water flow regulation on the dam was increasing risk of the desertification.
