Abstract
Ⅰ Introduction
The Shinagawa River basin was a region where deterioration of water quality was remarkable once, but in recent years the water quality is improving in the basin sewerage and hydrophilic projects. However, in the upstream part of the tributary located in the Sayama Hills there are still areas where the water quality has not improved, and surveys and research in the source area are important to identify pollution sources and improve water quality. In this report, we will examine the characteristics of the water environment centered on water quality, based on the results of surveying rivers around Sayama Hills.
Ⅱ target area
Sayama Hills is an area that spans 5 cities and 1 town in Tokyo and Saitama prefectures. Urbanization rapidly progresses from the high economic growth period, while forests are distributed around Lake Tama and Lake Sayama, leaving the environment of satoyama. Most of the rivers belong to the Shinagawa river system.
III Research method
After organizing and examining existing research, the field survey has been conducted once a month since November 2017. On the site, water temperature, temperature, electrical conductivity (EC), colorimetric pH and RpH, were measured, sampled and brought back to the laboratory, measurement of total organic carbon and analysis of major dissolved components were carried out.
IV Results and Discussion
There were many points of EC around 100-300 μS / cm, but high points of EC are seen upstream of the Karabori River and the Inferno River, and sewage and domestic wastewater may flow out. On the other hand, in some rivers and springs in the southwestern part, there were points and points showing good water quality below 100 μS / cm. The pH is around 7 and the RpH rises to around 8 in many places, but some points in the southwestern part also have more than 8 sites and the residence time may be relatively long.
The water quality composition shows Ca - HCO 3 type at many points, but nitric acid was detected mainly in the northwestern river. Suburban agriculture is thriving in the northwest area, and it is conceivable that many nitric acid is emitted because the sewerage penetration rate is relatively low. At the point of the Rokugetsu River in the eastern part, the Karibori River in the southeastern part, and the water for ignition stopping, it is extremely NaCl type water quality composition, which shows that a lot of treated water of domestic wastewater and sewage is flowing in. There is also a point where ammonia comes out mainly in the south, and the influence of domestic wastewater is considered.
Ⅴ Conclusion
Because it is an urban area, there are points where EC is high, there are still places where the water quality has not improved, and many sites where the influence of nitric acid by agriculture remains also distributed.
We will continue to conduct surveys in the future and carefully consider seasonal changes and so on.
Reference paper
Ryota Moriki, Koji Kodera (2009): Changes in river environment and water circulation in the suburbs of metropolitan area - Case study of the Shinagawa River basin -. Hydrological field physics research report, 13, 1-12.
