霞ヶ浦をめぐる住民運動に関する考察 : 都市化と環境保全運動

Neighborhood Movement for Environmental Conservation in the Area Around Lake Kasumigaura

淺野 敏久

地理学評論

Geographical Review of Japan

本稿の目的は,地域を単位として住民運動を考察し,住民運動の把握を通じて環境問題を考えることである.そこで昭和40年以降の霞ヶ浦をめぐる住民運動,とくに富栄養化問題に対して環境保全を求めた住民運動について,運動の担い手である2団体の調査をもとに考察する.
湖の富栄養化は全流域住民に関係することながら,住民運動としての反応がみられたのは,常磐線沿線の都市化地域においてであった。都市化地域の住民が運動を起こした背景には,飲料水としての霞ヶ浦の水に対する不安,都市化に伴う環境悪化,「水郷土浦」の喪失などがあった.都市化地域の運動であったため,富栄養化問題について飲料水の安全性や生活排水・工場排水の処理が重視されることになった.しかし,農村地域でより重要な畜産排水や水産養殖の対策は当事者のみの問題,あるいは技術的な問題とされ,地域の問題としては扱われていない.

The purpose of this paper is to clarify the regional characteristics of three main neighborhood movements in the drainage basin of Lake Kasumigaura, in particular, the environmental conservation movement. Two voluntary groups are mainly investigated. One is the Nature Conservation Society of Tsuchiura, and the other is the Liaison Conference for the Conservation of Lake Kasumigaura. Eutrophication of Lake Kasumigaura affects all the residents of the drainage basin, but only those in the urbanized area took action and agitated for environmental conservation. Eutrophication is essentially an urban problem.
Development of Lake Kasumigaura has progressed since a dam was constructed in 1963 in order to turn the lake into a freshwater lake. Its water resources have supported industrialization and population growth in the area. But water resource development, industrialization, urbanization, carp culture and stock raising have combined to result in the lake's steady eutrophication, and nowadays every summer the lake is host to dense growths of plankton which damage the carp culture seriously and give a foul smell to tap water in the surrounding area.
The area around the lake can be divided into four main zones (Fig. 4). The zone along the JR Joban-line is rapidly urbanizing because of the expansion of the Tokyo Metropolitan Area and the development of Tsukuba Academic City. The rate of population increase in this zone is the highest of the four (Fig. 5). A big steel plant is located in the Kashima zone. In the northern lakeside zone, carp culture and hog raising are important. The fourth zone includes the lowland along the Tone River and the upper and middle reaches of the Sakura River.
After the water resource development of the lake, three main neighborhood movements sprang up over the use of the lake. These movements centered around the first three of the above-mentioned zones (Fig. 6). In the JR Joban-line zone, environmental conservation is the object. In the Kashima zone, the residents are opposed to an Industrial Development Policy that prescribes drawing water from the lake for use in industrial areas. In the northern lakeside zone, the fishermen are protesting the Land Reclamation Project of Takahama-iri Inlet, begun in 1967.
In the JR Joban-line zone, two groups have been organized for environmental conservation. The Nature Conservation Society of Tsuchiura, organized in 1972, has played an important role in the movement. The Liaison Conference for the Conservation of Lake Kasumigaura was organized in 1981. Their chief interest is the solution of the eutrophication problem. Most of the members of the two groups live in Tsuchiura and Tsukuba Academic City.
Eutrophication affects all residents who live in the drainage basin, but most of those who are active in the groups live in the urbanized area (Fig. 7). In the area around the lake, only the residents of the urbanized area have to drink water from Lake Kasumigaura. The lake poses two problems for them. One is that the lake is a pool of sewage, and the other is that it is the source of drinking water. Water pollution inevitably causes doubts about the safety of drinkingwater from the lake. This fear motivated some of the residents to act.
The movement did not begin only in response to water pollution. The JR Joban-line zone has rapidly urbanized, and environmental deterioration is most serious in the area around the lake. Rapid environmental changes have made the residents nervous about environmental deterioration, including water pollution. Many residents of the urbanized area are interested in the environment. The water in Tsuchiura has a special meaning for persons who remember the area's past unspoiled beauty. Some of the residents who moved to this area from Tokyo are also keenly interested in the environment, and some of them have taken part in the movement.

Lake Kasumigaura

neighborhood movement

eutrophication

公害・環境工学 [ 519 ]

日本語

日本地理学会

古今書院

Copyright (c) 1990 公益社団法人 日本地理学会

[ISSN] 0016-7444

[ISSN] 2185-1735

[NCID] AN1016484X

[DOI] 10.4157/grj1984a.63.4_237

[NAID] 110000521329