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

Rokugo冲积扇位于日本北部北纬39°25′和东经140°34′左右。海拔90 m的近端扇与海拔45 m的远端扇之间的距离约为4 km，扇的无承压含水层主要为砾石，其导流率为10^0 ~ 10^<-2> cm/sec，比产率在20%以上。扇中央的含水层深度超过100米。大约70%的土地被用作水田。大约有6000名居民居住在远扇区域。他们每家都有自己的水井、水泵和供水系统。有相对较小的70个水泉，保持环境舒适，用于家庭用途。年地下水水位变化规律，即5 - 8月灌溉期出现高水位，非灌溉期出现低水位，特别是在积雪最大的时候。在非灌溉期，利用4个流域进行人工补水，以提高地下水资源。盆地。1-4号，建在风机的中央部分。本文展示了人工补给对2号盆地地下水位形成的影响，2号盆地底部面积为2,120m^2，深度为3m。研究结果是基于1998年9月8日至11月10日3次人工补给的结果，第1次为63 d，第2次为1998年11月15日至1999年4月5日141 d，第3次为1999年4月19日至29日10 d。向盆内供水100升/秒。以下是结果。从1到3是通过位于盆地边缘以西2.3m处的观测井进行测量得到的。在每一个案例中，最初的地下水水位都超过海平面57.5米。2 .开始供水后，第1例地下水水位在43 h出现60.39m的最大值，第2例在56 h出现60.39m的最大值，第3例在172 h出现60.66m的最大值。停止供水后，地下水位开始下降。第一例2.49m的水平在47小时内衰减，第二次3.71m的水平在91小时内衰减。对于第三种情况，由于融雪导致入渗速率增加，腐烂现象较少。和4。人工补给在盆地下形成了地下水丘。在盆地西侧，由于地下水丘的形成，使地下水位上升。人工补给含水层加强了六谷冲积扇的地下水循环，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