The Research on the Effect of the River Flow Condition Change on the Agricultural Water Utilization by the Global Warming

1.融雪成熟期4月，大仓水坝(宫城县)总径流深度为371 mm，土里水坝(富山县)为742 mm。随着气温上升3℃，大仓大坝的深度减少了33毫米，图里大坝的深度减少了82毫米。大仓水坝融雪径流为262毫米，土里水坝为620毫米。融雪径流占总径流的平均比例为70%，土里大坝为83%。当气温升高4℃时，大仓大坝的平均比例为35%，图里大坝为45%。这样就可以证明，如果全球变暖加剧，降雪的大坝功能明显降低。以仙台平原研究对象流域之一的大仓水坝为研究对象，观察水稻开割时间与农业用水的关系。仙台气温升高4℃，与目前广岛和福冈的气温基本持平。在水稻成熟期，通过提早5月上旬或4月上旬插秧，可使水稻遭受高温伤害。因此推测，如果全球变暖加剧，它将在6月初在宫城县插秧，并将在10月初收获。然而，预计6月份是河流流量最小的时候，再次，融雪径流量也无法因气候变暖而预期，并面临极端缺水。在这个问题上，还需要进一步研究。

1. In April in the snowmelt mature stage, total runoff depth is 371mm at the Okura dam(Miyagi prefecture), and 742mm at the Touri dam(Toyama prefecture). The depth decreases 33mm at the Okura dam, and 82mm at the Touri dam on the temperature 3℃ rise.2. Snowmelt runoff is 262mm at the Okura dam, and 620mm at the Touri dam. And the mean ratio of the snowmelt runoff to the total runoff is 70%, and 83% at the Touri dam. When the temperature increases 4℃, the mean ratio is 35% at the Okura dam, and 45% at the Touri dam. Like this, it was able to be demonstrated the fact that the dam function of the snow remarkably lowered, if the global warming advanced.3. It tried to observe the relationship between rice paddy crop bill time and agricultural water with Okura dam which is one of the research object basin in Sendai Plain.4. It is almost equalized with present temperature of Hiroshima and Fukuoka, when the temperature of Sendai increases 4℃, and it consists. The high temperature injury will be received in the ripening stage, when rice transplanting is done by accelerating May early month or April early month. Therefore, it is guessed with that it does the rice transplanting in Miyagi Prefecture in June early month, if global warming advances, and will harvest it in the October early month.5. However, it is anticipated June that it is the time in which there are most small river flow, and again, that the snowmelt runoff volume can not be expected by the warming either, and that it faces the extreme water shortage. On this problem, further examination is necessary.