기후변화 연동 4대강 유역 지하수 함양 및 이용가능량 산정 기법 개발

Abstract

Coupled Model Development between Groundwater Recharge Quantity and Climate Change in River Watershed Global climate change is destroying the water circulation balance by changing rates of precipitation, recharge and discharge, and evapotranspiration. The Intergovernmental Panel on Climate Change (IPCC 2007) makes “changes in rainfall pattern due to climate system changes and consequent shortage of available water resource” a high priority as the weakest part among the effects of human environment caused by future climate changes. Groundwater, which occupies a considerable portion of the world's water resources, is related to climate change via surface water such as rivers, lakes, and marshes, and “direct” interactions, being indirectly affected through recharge. Therefore, in order to quantify the effects of climate change on groundwater resources, it is necessary to not only predict the main variables of climate change but to also accurately predict the underground rainfall recharge quantity. In this study, the authors selected a relevant climate change scenario, In this context, the authors selected A1B from the Special Report on Emission Scenario (SRES) which is distributed at Korea Meteorological Administration. Weather data for rainfall and temperature with the period between 1971 and 2100 was used in this study. Actual observation data from the Korea Meteorological Administration from 1970 to 2000 was used and the weather data obtained from the SRES A1B scenario was used for the data between 2001 and 2100. The 30-year observation and prediction averages were used in order to promote efficiency in processing the enormous amount data. and extracted future temperature and rainfall changes. By using data on temperature, rainfall, soil, and land use, the groundwater recharge rate for the research area was estimated by period and embodied as geographic information system (GIS). With regard to the study area, average temperature and accumulated rainfall were calculated as 11.69℃ and 1,018.04mm between 1970 and 2000, 12.59℃ and 981.04mm between 2001 and 2030, 13.79℃ and 1,222.49mm, between 2031 and 2050, and 15.511℃ and 1,192.03mm between 2051 and 2100, respectively. With regard to the groundwater recharge quantity, the climate data obtained from the above-mentioned process was used as input data, and the soil map organized for calculation of CN values was used, and the data provided by USGS and EPA was used for the material properties of the soil. In order to calculate the groundwater recharge quantity, Visual HELP3 was used as main model for groundwater recharge, and the physical properties of weather, temperature, and soil layers were used as main input data. The temporal variation of the groundwater recharge quantity of the study area between 1971 and 2100 was calculated to correspond with the data for climate change at percentage : 26.19% between 1971 and 2000, 25.87% between 2001 and 2030, 27.33% between 2031 and 2050, and 25.45% between 2051 and 2100, respectively. Also, the spatial variation of the groundwater recharge showed that in the period between 2051 and 2100, the quantitative differences between high and low recharge region are more severe than the period between 1971 and 2000. General changes to water circulation due to climate change have already been predicted. In order to systematically solve problems associated with how the groundwater resource circulation system should be reflected in future policies pertaining to groundwater resources, it may be urgent to recalculate the groundwater recharge quantity and consequent quantity for using via prediction of climate change in Korea in the future and then reflection of the results. The space-time calculation of changes to the groundwater recharge quantity in the study area may serve as a foundation to present additional measures for the improved management of domestic groundwater resources.