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

罗库戈冲积扇位于日本北部，北纬39°25‘，东经140°34’。近扇距海拔90m，远扇距45m，距离约4公里，扇体潜水含水层以砾石为主，导水率在10~10 cm/s量级，比采出度在20%以上。风机中心的含水层深度超过100米。约70%的土地被用作水田。大约6,000名居民居住在远端风扇区域。他们在每个家庭都拥有自己的水井、水泵和供水系统。有70个相对较小的水泉，保持环境舒适，供家庭使用。年地下水位有规律的变化，即5-8月灌溉期出现高水位，非灌溉期出现低水位，特别是在积雪达到最大值的时候。Aquif…的人工补给更多的呃在非灌溉期使用了四个流域，以提高地下水。盆地。1-4号盆地建造在扇体的中央，这里展示了人工补给对2号盆地地下水丘形成的影响。2号盆地底部面积为2120m，深度为3m。这个结果是根据三次人工补给的结果得出的，第一次是从1998年9月8日至11月10日(63天)，第二次是1998年11月15日至1999年4月5日(141天)，第三次是从4月19日至1999年4月29日(10天)。向流域供水100%L/秒。结果如下。通过使用位于盆地边缘以西2.3米处的观测井进行测量，获得了1至3。在每种情况下，最初记录的地下水流量都在海平面以上约57.50米。供水后43小时出现最大水位60.39米，第二例56小时出现最大水位60.39米，第三例172小时出现最大水位60.66米。停止供水后，地下水位开始下降。第一例在47小时内下降到2.49万，第二例在91小时内下降到371万。对于第三种情况，由于积雪融化导致入渗率增加，所以衰减不是很大。4.人工补给在盆地下方形成了地下水土丘。在盆地西向地区，由于地下水丘的形成，地下水位上升。含水层的人工补给促进了Rokugo冲积扇的地下水循环，实现了地下水的可持续利用。较少

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