Abstract
In the irrigation district in the lower Ili River basin, a crop rotation system which combines paddy rice and field crops is practiced. Upland crops use the groundwater which is raised by seepages from canals and rice cropped fields. However, excessive rising of groundwater level on upland cropped fields causes salinization. Therefore, it is necessary to control groundwater level appropriately and to perceive temporal and spatial characteristics of groundwater level fluctuation is quite important for adequate groundwater level control.
This study analyzed temporal and spatial distribution of groundwater level fluctuation. The results are summarized as follows; (1) Groundwater level had risen sharply since 1970s when cultivation of paddy rice was officially introduced and was highest in 1980s when amount of irrigation water supply peaked. Recently, groundwater level showed the decreasing trend with decrease of amount of irrigation water supply. (2) Spatial distribution of groundwater level inclined with ground surface inclination during non-irrigation period while spatial distribution of the raised groundwater level was not uniform during irrigation period. (3) Agricultural land use and condition of drainage canals affected groundwater level fluctuation.
