The deterioration of hot spring resources and the change of chemical constituents with the development of spa

Abstract

General aspects of the deterioration and typical examples in some hot springs (Atami, Shirahama, Isawa · Kasugai, and Syuzenji Hot Springs) are outlined in this report in connection with the change of chemical constituents. (1) Deterioration of thermal spring resources generally occurs accompanied with the following phenomena: a) drawdown of the water level in thermal water wells. b) lowering of temperature of thermal springs. c) change of the water quality (salt water encroachment in the coastal region and decrease in concentration of chemical components resulting from the intrusion of underground water in the inland area). (2) Typical examples of the deterioration are summarized as follows; Name of hot springs Characteristic features of the deterioration Intrusion of salt water with a gradual drawdown Atami (Shizuoka Pref.) of thermal water level due to the over discharge of thermal water. Intrusion of salt water caused by the pressure Shirahama drop in the thermal water reservoir due to the (Wakayama Pref.) degassing caused by the discharge of a large amount of thermal water containing carbon dioxide. Isawa · Kasugai Intrusion of underground water caused by the pres (Yamanashi Pref.) sure drop in the thermal water reservoir through the discharge of a large amount of thermal water. Intrusion of cold and tepid underground water by Syuzenji the abnormal drop of thermal water level due to (Shizuoka Pref.) the over discharge of thermal water. (3) It has been revealed from the analyses of the statistical data of Environment Agency that the deterioration of hot spring resources in Japan is gradually progressing.