Using the monthly groundwater depth at 104 stations and the monthly precipitation at 97 stations across the Huaibei plain

China

covering the period of 1980-2007

trends and characteristics of groundwater depth were analyzed

and regional responses of the ground water depth to spatialtemporal distribution of precipitation were also investigated. The results indicated that: (1) The groundwater depth was the smallest in the 1980s and was the largest in the 1990s. Massive agricultural irrigation due to the extreme droughts was the major driving factor behind deepening processes of the groundwater level. (2) The groundwater level in the south was less deep than that in the north

and groundwater depth was the deepest in northeastern Huaibei plain. On a seasonal scale

the average depth of groundwater showed the smallest in summer and the largest in spring. (3) Groundwater depth increased during the growing season (from March to September) during 1980-1985 and 1990-2007

and decreased during 1985-1990. (4) Although precipitation reduced

the groundwater depth was decreasing in the central and western Huaibei plain from March to May and in September. In eastern region

the groundwater depth was decreasing from August to September

caused by decreased precipitation.