No.057 研究課題 / Project
多摩川の下流における支流や海水の混入について－川崎市立宮崎中学校科学部の活動－Mixing of tributary water and sea water in the lower Tama RiverActivities of Science Club, Miyazaki Junior High School, Kawasaki| 一般研究 General Research |
No.057 |
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| 代表研究者 Principal Investigator |
青柳 隆二 Ryuji Aoyagi |
| 所属（採択当時） Affiliation |
前、川崎市立宮崎中学校教諭 Teacher, Kawasaki Municipal Miyazaki Junior High School |
| 研究内容要約 Research Summary |
８３年から２年間継続した「多摩川のにごりの研究おもに二子橋付近について」で、川崎側が東京側に比べて汚れている原因は、二子橋より約５００ｍ上流で多摩川に合流する都市型河川の平瀬川の影響と考えた。 そこで多摩川本流に平瀬川の水が混合して同化していく様子を調べたいと考えた。 同時に二子橋付近で東京側で本流に合流する野川についても調べる。 多摩川の最下流のダムは丸子橋のそばで、このダムより上に海水は来ないので、ダムより下でどこまで海水が入ってくるのかも調べることにする。 調査方法は、平瀬川、野川、およびこの２支流と合流前の多摩川本流の水質（ＮＨ4 Ｃｌ Ｓ０4）、水位、流速を測定する。 次に平瀬川については合流後に通過する新二子橋と二子橋の橋上、水位が低く渡河できる日は、野川の合流点より下流約２００ｍ線と、さらに約２００ｍ下った線で各６地点で採水して、分析成分の含有率の違いから支流に混ざっていく様子を混合率で求める。 Research on the turbidity of the Tama River , especially around Futago Bridge was conducted for a period of two years from 1983. It explained why river water in the Kawasaki side is more turbid than in the Tokyo side: it is caused by an urban river, the Hirase River, which joins the Tama River about 500 m upstream from Futago Bridge Given this background, we examined how waters of these two rivers?the Tama River and the Hirase River ?mix. At the same time, the Nogawa River which joins the Tama River from the Tokyo side around Futago Bridge , was also studied. Near Maruko Bridge there is the most downstream dam, and sea water does not reach areas upstream of the dam. We examined how far up the River (downstream of the dam) sea water could backflow. We measured water properties (NH4, Cl, SO4), water levels, and flow rates of the Hirase River and the Nogawa River , as well as of the Tama River upstream of the meeting points with these two tributaries. The selected water collection sites were Shinfutago Bridge and Futago Bridge which cross over the Tama River downstream of the meeting point with the Hirase River . If the water level was low enough for us to wade across the river, the following lines were also selected as water collection sites: a line 200 m downstream of the meeting point with the Nogawa River , and a line further 200 m downstream. Then, we determined six water collection points for each of these sites. Water samples were collected at these points and analyzed to investigated what substances were present. Based on the difference in contents between samples, we calculated the mixing ratio to understand how water of these rivers mix. |
| 共同研究者 Collaborators |
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