Geochemical study of groundwater in the Sho river fan, Toyama Prefecture for heat usage by geothermal heat pump

Flow analysis of groundwater with seasonal variation of temperature, electric conductivity, and oxygen isotope for heat utilization in Sho River alluvial fan, Toyama, Japan

“…There are coarse layer deposits in the upper and central areas of the fan. In addition, two or three clay layers are present at the end of the fan around Takaoka (e.g., Iwatake et al, 2013). Quaternary unconsolidated or semi-consolidated sediments are distributed on the alluvial plain and fan.…”

“…There are many studies of water movement in alluvial fans (e.g., Mizutani and Oda, 1983;Li et al, 2008;Hidalgo and Cruz-Sanjulian, 2001;Mizutani et al, 2001;Chkirbene et al, 2009;Yuan et al, 2011;Vanderzalm et al, 2011;Tsuchihara et al, 2011). Recently, several reports have been published on the chemical characteristics of groundwater in Japan for the purpose of using groundwater heat (Takizawa 2011;Ioka et al 2013;Iwatake et al 2013;Yamada and Ueda 2018;Mori et al, 2020;Okano et al, 2020;Matsuura et al, 2021). There also has been research on the environmental in uence on water quality and water temperature changes of reinjected groundwater after heat extraction (e.g., Hartog et al 2013;Saito and Komatsu 2014;Park et al 2015;García-Gil et al 2016;Gjengedal et al 2019;Pophillat et al 2020;Pratiwi and Trutnevyte, 2021).…”

“…There are previous reports on the state of recharge and groundwater ow in the Sho River alluvial fan based on stable isotope and chemical components (Mizutani and Oda, 1983;Kato et al, 1984;Mizutani et al, 1987). Recently, Iwatake et al (2013) reported a linear relationship between δD and δ 18 O values for groundwater and river water in the region and posited that groundwater originated as a mixture of Sho and Oyabe River waters and precipitation in varying proportions. The δD and δ 18 O values for groundwater vary from − 47‰ to − 65‰ and from − 8.1‰ to − 10.6‰, respectively.…”

“…The range of variation in δD and δ 18 O values is smaller for the Sho River than for the Oyabe River, and the Sho River originates from higher elevations. Iwatake et al (2013) also analyzed the chemical composition of groundwater collected in August 2011 and showed that groundwater is enriched in Ca 2+ and HCO 3 − by dissolution of carbonate rocks. They evaluated this area for the applicability of GSHP and the degree of scale creation by chemical components such as iron and calcium carbonate.…”

Preface: Recent progress in environmental hydrogeochemistry

“…The issue contends ten papers (8 articles and two notes) covering major ion geochemistry, stable isotopic and trace element research related to the terrestrial hydro-system, air pollution, speciation measurements and analytical developments. Iwatake et al (2013) using chemical and isotopic (D, O) compositions of 56 water samples from the Sho River fan, Toyama, northern part of central Japan, discussed the ground water geochemistry, water quality, origins and water flow. The geothermal gradient is about twice as other areas in Japan and it might mean that high temperature geothermal sources lay under the study region.…”