Abstract
Flow rate measurement and monitoring of water quality were conducted to reveal characteristics of coastal groundwater at intertidal zone in Matsugaura Beach, Kagoshima Prefecture, Japan. The coastal groundwater flow rate was estimated as much as 12.6m3/day. Nutrients supply by the groundwater was estimated as 45.7g-N/day and 0.5g-P/day. Soil around a study site is of volcanic debris and hinterland is classified as welded tuff. Due to high permeability of the soil, reasonably warm climate, high rainfall, and much utilization of fertilizer to tea filed, local groundwater contains concentrated nitrate and low pH value. It is shown that the coastal groundwater contains concentrated nitrate (300μmol/L) and low pH value (6.3). In addition, salinity of the coastal groundwater is 0.1‰ to 2.9‰. Therefore, it is evident that the coastal groundwater affected less by sea water at this area.The results show that the coastal groundwater is a key mechanism to supply into a coastal zone and maintain the local ecosystem.
