Assessment of agricultural drought effects on groundwater system using the standardized groundwater level index (SGI) in S. Korea

To evaluate the effects of drought on groundwater system in rural areas, the standardized groundwater level index (SGI) was applied to groundwater monitoring wells over S. Korea. Moreover, accumulation period (AP), representing the month with the highest correlation coefficient between SGI and the standardized precipitation index (SPI), was calculated for monitoring wells. In this case, correlation analysis was performed to investigate differences in the response of precipitation and groundwater level to drought using SPI. Groundwater level data from 68 monitoring wells were used for the analysis. The response time of groundwater level to precipitation appeared to be very short, but the groundwater level did not go with SPI during the long-term drought. Results of correlation analysis between reservoir level and SPI show high correlation on the relatively long AP. The results of analysis between SGI and SPI appeared that the AP values ranged from 1 to 3 months for most of the wells indicating that the total amount of groundwater will not decrease significantly in long-term drought periods unlikely it of reservoirs with the high AP values. The nationwide maximum AP values between SGI and SPI were around 4 in the central part of S. Korea, while the minimum AP values were around 2 in the eastern and western part of S. Korea. Consequently, it could be concluded that the wells with low AP value tend to respond to short-term drought, but it has little effect on groundwater system when the long drought occurs. 

Acknowledgement: This research was supported by the Institute of Planning and Evaluation for Technology in Food, Agriculture, and Forestry (IPET) [Grant number 320046053HD020].