高松地域における地下水環境の観測

抄録

Field measurement of groundwater level and analysis of groundwater quality were carried out quarterly to clarify the present situation of confined and unconfined groundwater in Takamatsu district. Our measured data, the groundwater data obtained by public sectors and other relevant digital data were arranged on GIS software to develop the database on hydrological cycle. It is confirmed that the contours of unconfined groundwater level run nearly parallel to those of topography and that the groundwater level has shown seasonal variation of about 1 to 2m. Nitrate nitrogen of unconfined water at several locations has exceeded the environmental standard, which may have come from the overuse of fertilizer. The level of confined groundwater has gradually increased owing to the regulation of groundwater uptake. The pH value of confined subsurface water has unchanged whereas the levels of iron and evaporation residue have decreased.