富山県庄川扇状地浅層地下水の水系区分

抄録

Chemical analyses of ground and river waters of the Shogawa Fan, Toyama, have been made to identify sources of water and to interpret the flow direction of ground water in aquifers in the Fan. The analyses indicate 5 main ground water systems to exist in the Fan and its surrounding areas. The 2 systems are recharged by seepage from the Oyabe and Sho Rivers, respectively, and the others are by local rainfall in the Tonamiyama and Hotatsu Hills and Takashozu Range, respectively. Intermixing of water between the systems is also found near the foot of the Fan. Infiltration from the surface is suggested to interpret the increase in the sodium, chloride and sulfate con- centrations of ground waters. The increase in the calcium, magnesium and bicarbonate concentrations of ground waters is due probably to the dissolution of carbonates, such as CaCO₃+CO₂+H₂O=Ca²⁺+2HCO₃^-, in the aquifers. Inflows from mineral springs into the ground waters are also detected near the foot of the Tonamiyama and Hotatsu Hills.