GVG (average spring groundwater level)

The GVG card, Average Spring Groundwater level. For the average spring groundwater level, groundwater levels are averaged on 14 March, 28 March and 14 April each year. The average of these annual values over a period of at least 8 years, in which no interventions have taken place, is used as GVG.

GVG卡：春季平均地下水位。针对春季平均地下水位的计算，每年将取3月14日、3月28日及4月14日的地下水位数值进行平均，得到该年度的春季地下水位均值。随后，在至少8年且未发生任何人为干预的时段内，对上述年度均值求取平均，所得结果即作为GVG指标。