Changes in the Hydrological Environment in Tokyo
Changes in the Hydrological Environment in Tokyo
复制标题
东京都水文环境的变化
DOI：
10.5026/jgeography.105.4_459
复制
发表时间：
1996
影响因子：
3.1
通讯作者：
T. Arai
中科院分区：
文献类型：
--
作者：
T. Arai
本文分析了东京水文变化的两个方面。第一个是从公元前到公元前的河道、运河和明渠的变化。1890年，任。1985.地表沃茨的位置是从地形图上追踪出来的。除东部低地的3个特殊区外，23个特殊区的平均河流密度在1890 ~ 1910年间为1.4km-1，而1985年则下降到0.49km-1。在这100年里，有几个病区的密度下降到10%以下.小河渠的减少早在20世纪20年代就开始了，到1985年，许多小河渠消失了。地表沃茨的减少与城市供水和排水系统的扩散密切相关，因此，估算了近40年来人为调水引起的水量平衡。每隔10年计算每个区和城市的水平衡。资料来源于《东京统计年鉴》和有关自来水厂的各种统计资料。总供水量包括市政用水和工业用水。在20世纪60年代和70年代，东京中心区以水深（高度）表示的年总供水量约为6 m，即约为东京年降雨量的4倍。23个病区在70年代供水深度均超过年降雨量。自20世纪80年代以来，由于循环利用系统的建立，水的消耗和供应都有所减少。由于供水率高，1975年中央区自来水厂地下管道渗漏深度达1 my-1。第一个污水系统于20年代建成，但直到最近才完成对东京所有地区的覆盖。因此，在1980年之前，有超过1 my-1的未经处理的水从几个病房排放，造成河流的高度污染。地表沃茨的历史变化及其污染可以用人为引起的水平衡变化来解释。必须强调的是，人工输水是理解城市水文的关键因素。
Two aspects of the hydrological change in Tokyo are analyzed in this paper. The first is the changes in river courses, canals and open aqueducts from ca. 1890 to ca. 1985. The position of surface waters were traced from the topographical maps. Average stream density in the 23 special wards area except for three wards in the eastern lowland was 1.4 km-1 during a period from 1890 to 1910, while it reduced to 0.49 km -1 in 1985. In several wards, the density reduced to less than 10 % during this 100 years. The diminution of small rivers and canals began as early as 1920's, and many of them disappeared by 1985.The reduction of surface waters is closely related to the diffusion of municipal water supply and sewerage system, therefore, the water balance caused by the man-induced water transport was estimated for the recent about 40 years. The water balance was calculated for each ward and city for each 10 years interval. Data were taken from several kinds of statistics on waterworks and “Statistic Yearbook of Tokyo”. The total water supply includes the municipal water and the industrial water. The annual amount of total supply expressed by water depth (height) was about 6 m during 1960's and 1970's in the central district of Tokyo, that is, about four times of the annual rainfall in Tokyo. The depth of total water supply exceeded the annual rainfall in all the 23 special wards in 1970's. The consumption and supply of water have been reduced since 1980's according to the establishment of recycling system. Because of the high supply rate, the depth of seepage from underground pipes of the waterworks amounted to 1 my-1 in 1975 in the central wards.The first sewerage system was established in 1920's, but the coverage for all the areas in Tokyo was not completed until the recent. Therefore, more than 1 my -1 of the untreated water had been discharged from several wards before 1980 causing the high pollution of rivers. Historical changes in surface waters and their pollution can be explained in connection with the changes in man-induced water balance. It must be emphasized, that the artificial water transport is a crucial element in understanding the urban hydrology.