For seasonal groundwater ...

For seasonal groundwater level change, one usually drills a narrow well ( diameter 5 cm) down to the lowest water table in the dry season, backfills with crushed rock, inserts a slotted PVC pipe and into it a pressure transducer, that logs the pressure of water column, converts it into height and logs the data at the desired interval ( 15 minutes, or hourly, or daily). The data can be downloaded from the transducer on site visits, or if realtime monitoring is required, connect that to an external datalogger with a cellphone modem to send the data out. The expensive part is the sensor, usually $500-700 ( Insitu trolls, Campbell Scientific), but one can also jave lower cost options such as Odyssey capacitance probes, or ulltrasonic rangers if one is looking a water level in an open water body. The data is in text files that can be opened in Excel for QA/QC, plotting and analysis. Cheers