Abstract
1. IntroductionIn order to perform river management and environmental preservation of a river basin, grasp of the water area environment in a valley unit is needed.by the spread of GIS(s), space grasp of the river basin was markedly alike, and became simple in recent years, and expression of the various water quality formation factors of rivers, such as climate and geographical feature, was attained.By the research consortium of "geography of water environment", "water [of a river basin ] environmental database" creation is tried in 2000 and afterwards.At this laboratory, research of river characteristic grasp accomplished by the first-grade rivers and large-scale branches (2008, Shinano River branch Uono River, Morimoto), such as Teshio River (2006, Shimizu), and the Kitakami river (2009, Hirayama).This research performs valley characteristic grasp of the basin system valley classified by hips as part of a water environmental database.Although there is a report by Mt. Yotei springwater and public water quality observation in a here region, there is no example which the water analysis of the whole basin system including a branch constituted. The water analysis by a main ingredient and the valley characteristic analysis using GIS are introduced. 2. method of research Natural regional geography creation according the public creation data of digital national information etc., etc. to space grasp on the river scale for GIS software was performed.Moreover, in order to perform water quality characteristic grasp of the Shiribetsu River basin system, the like [ 50 point ] sampling of the river Mogami style part according to a main stream, the branch lower stream more than a 2nd order style, springwater, and it was performed late in 5, 7, and September, 2012, and local observation (temperature, water temperature, a flow, EC, pH, RpH) was performed.Main componential analysis by TOC and ion chromatography was conducted after filtering a sample at the laboratory, and figure-ization by GIS software performed clear grasp of the valley characteristic. 3. result and consideration Various rivers, such as acid rivers, such as a sulfur river, a fake Koanbetsu river, etc. before and after [ pH 4.0 ] carrying out the origin to Iwaonupuri(1,116 m), and a river where springwater supply is high including around pH 8.0 Makari rivers etc., exist in a valley. Most valleys serve as a forest and EC of the mouth-of-a-river part late in May shows that there are little 95 micrometer/cm and anthropogenic impact.However, in the small-scale river of Dairy Belt or the cultivated land style neighborhood, pH and EC are subject to artificial high influence. 4. conclusion It became clear that the river which has the various characteristics in the Shiribetsu River basin system by this research existed.I would like to continue investigation, to grasp year change and to continue to solve the basin system characteristic and water quality formation of each river.
