<論文>ハワイ島における湧水・井戸水・河川水等の水質特性

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The characteristics of major dissolved components about the water quality of the spring, well and river waters in relation to the hydrological environment of the Hawaii Island were considered and concluded in the following. As for the Hawaii Island consists of a volcanic island and the rainfall distribution is resulting a remarkable regional difference by the north-east trade wind, those factors have a great influence on the hydrological environment. The running water of the river only existed in the area of the north-east side of the Mt. Mauna Kea and the Kohara mountain range, and a part of the south slope of the Mt. Mauna Loa at the time of a rainfall, in spite of large quantity of the precipitation. The degree of infiltration of rain water to the underground in the Hawaii Island is large reflecting of the porosity and high permeability of volcanic rocks, therefore the water use is mainly composed of the well water pumping up in this island. A lot of groundwater stored in the underground of the volcanic island are flowing out to the sea as a coastal spring water and submarine spring water in accordance with the groundwater flow system, without being used. In the Hawaii Island which is an ocean island, the groundwater is existed as a large lens-shaped bodies, that is commonly known as the Ghyben-Herzberglens. The groundwater in the boundary with sea water is turned a salty groundwater which called a brackish groundwater. The brackish groundwater is pumped up by the deep well that was dug in a coastal area and also is naturally discharged out as a spring water in the beach and the sea bottom. The inland waters as river, spring and basal groundwater sampled in Hilo area and the north end area are including a little bit to an appropriate volume of the dissolved component. Most of the water belong to the Ca-HCO3 composition type, a part of water belong to the Na-HCO3 type and the intermediate type between the Na-Cl type and the Mg-HCO3 type, because the influence of sea salt particles transported by wind. The water composition of groundwater in South Kohara area which located in the extremely scarce precipitation shows the intermediate type between the Na-Cl type and the Mg-HCO3 type as same as the water of north end area of the island. However, the dissolved component of the groundwater in South Kohara area is fairly high density and is included the quantity of two or three times to that of the north end area. The tap water of Kilauea area is extremely little contained the dissolved component and be doing close to the rain water composition. Waters with the tap water in Kona area at the west coast of the island, the spring water of the Punaluu beach and the Lokowaka spring water are included a lot of minerals. The water composition of these waters shows the Na-Cl type as same as sea water and is turned a brackish groundwater. As for the Pohoiki hot spring located in the south-east area is mixed with the salt water, the water composition is contained extremely much volume with the same Na-Cl type as the sea water. Submarine discharged groundwater as a submarine spring and/or a coastal spring is considered to be mixed with sea water and turned a brackish water. The mixing rate of the salt water to the groundwater about the groundwater of the Kona area is calculated with about 2%. Similarly, the mixing rate is calculated with 2.5% at the coastal spring water of the Punaluu beach, with 9.6% the spring water in the lava crack of the Kaena point, with 12% the spring water of the Lokowaka pond of the Hilo and with 22% the Pohoiki hot spring, respectively. The silica acid (SiO_2) concentration is observed with tendency to regional distribution, its concentration is low density in the much rainfall area and is higher density in the small rainfall area. Also, the nitric acid ion (NO_3) that is the guideline of contamination was not detected in the most place of the island. As for granted that the nitric acid ion was detected being becomi
敬愛大学・千葉敬愛短期大学の論文

<論文>ハワイ島における湧水・井戸水・河川水等の水質特性

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