Table 1.

Distribution of the wells monitoring groundwater flow velocities and directions.

Locations	Hills of northern Hubei	Jianghan Plain	Jiuling Mountains	Coastal plain on the Leizhou Peninsula
Well number	Well ZK106	Well ZK01	Well DR01	Well HT35	Well PH33
Coordinates of the wells	114°1632′E 31°0917′N	114°4214′E 30°4581′N	113°9928′E 29°0830′N	110°4759′E 20°5631′N	110°3793′E 20°6384′N
Lithology of the monitored aquifer	Schist	Limestone	Granite	Basalt	Basalt
Depth of the well (m)	200	500	870	35	243
Altitude (asl) of the wellhead (m)	130	21	283	14.8	10.8
Altitude of the well base (m)	− 70	− 479	− 587	− 20	− 232.2
Groundwater depth (m)	8.6	1.4	2.52	7.1	18.1
Monitoring depth (m)	129	120, 134	120–236	13, 14, 15	21–30
Monitoring elevation (m)	1	− 113 ~ − 99	47 ~ 163	− 0.2 ~ 1.8	− 19.2 ~ − 10.2