「Artificial Kecharge of Groundwater and Change of Groundwater Level」: For Progress of Control System

六乡冲积扇位于日本北方约39°25' N，140°34' E。近源扇海拔90 m，远源扇海拔45 m，相距约4 km，扇体含水层以砾石为主，导水率为10 ~ 10 ~ 10 <-2>cm/s，给水度大于20%。扇形体中心含水层深度超过100米。约70%的土地面积用于水田。约有6，000名居民居住在远扇地区。他们在每个家庭都有自己的水井、水泵和供水系统。地下水水位年变化有一定规律，即5 ~ 8月灌溉期水位高，非灌溉期水位低，特别是积雪最大期水位低。人工回灌可使地下水保持较高的水位，使地下水水位保持较高的水位。 关于我们 在非灌溉期进行了四个流域的强化灌溉，以增加地下水。盆地。号在此，我们展示了人工补给对2号盆地（底部面积为2,120 m^2，深度为3 m）地下水土丘形成的影响。结果是基于三次人工回灌的情况，第一次：1998年9月8日至11月10日（63天），第二次：1998年11月15日至1999年4月5日（141天），第三次：1999年4月19日至4月29日（10天）。以100升/秒的速度向水池供水，结果如下。1 ~ 3是利用位于盆地边缘以西2.3m处的观测井测量得到的。最初的地下水狂欢记录约。57.50米以上的海平面在每一个情况下。供水开始后，第一种情况下最高地下水位出现在43小时内，为60.39m，第二种情况下出现在56小时内，为60.39m，第三种情况下出现在172小时内，为60.66m.地下水水位在停止供水后开始下降。第一种情况下，2.49米的水平在47小时内衰减，第二种情况下，3.71米的水平在91小时内衰减。对于第三种情况，由于积雪融化导致土壤入渗速率增加，土壤的衰减不明显。人工补给在盆地下形成地下水土丘。在盆地西向地区，由于地下水丘的形成，地下水位升高.人工补给地下水，加强了六乡冲积扇地下水循环，实现了地下水的可持续利用。少

The Rokugo alluvial fan lies around 39°25' N and 140°34' E in northern Japan. The distance between the proximal fan on 90 meters above sea level and the distal fan on 45 meters is about four kilometers, Unconfined aquifer of the fan consists mainly of gravel, of which hydraulic conductivity is in order of 10^0〜10^<-2> cm/sec and specific yield is over 20%. The depth of the aquifer is over 100 meters in the center of the fan. About 70% of the land surface is used for paddy field. About 6,000 inhabitants live in the area of the distal fan. They privately posses well, pump and water supply system of their own in each homes. There are relative small 70 water springs which keep environment comfortable, and used for domestic purposes.Annual groundwater levels regularly change, I.e. high water levels occur during irrigation period from May to August, and low water levels occur during nonirrigation period, especially around the time when snow cover reaches maximum.Artificial recharge for aquif … More er using four basins has been performing during nonirrigation period in order to enhance groundwater. The basins. Nos. 1-4, were constructed on the central part of the fan.We show here effects of artificial recharge on the formation of groundwater mounds under the basin No.2 which equips 2,120m^2 bottom area and 3m depth. The results are based on the cases of artificial recharge which have done three times, first: from September 8 to November 10, 1998 (63 days), second: from November 15, 1998 to April 5, 1999 (141 days) and third: from April 19 to April 29, 1999 (10 days). Water of 100 l/sec was supplied to the basin.The followings are results. From 1 to 3 were obtained through the measurements using an observation well located at 2.3m west from the edge of the basin.1. Initial groundwater revels recorded ca. 57.50m over sea level in each of the cases.2. After beginning of the water supplies, the maximum groiundwater level of 60.39m appeared in 43 hours for the first case, of 60.39m appeared in 56 hours for the second case and of 60.66m appeared in 172 hours for the third case.3. Groundwater levels began declining after stopping the water supplies. The level of 2.49m decayed in 47 hours for the first case and 3.71m decayed in 91 hours for the second case. For the third case, the decay appeared not so much because infiltration rate increased caused by snow melting.And 4. The artificial recharges formed groundwater mounds under the basin. In the area of western direction of the basin, water tables were raised due to the formation of the groundwater mounds.5. Artificial recharge for aquifer has been enhancing groundwater cycle in the Rokugo alluvial fan and there realizing sustainable groundwater use. Less