Serving parts of North West London and the Home Counties.

Groundwater levels

East Region


East region groundwater levels

*The long term average (LTA) has been calculated statistically, using the long term data record for this hydrograph. The respective drought zones are used as operational triggers, and have been derived using the LTA.


Groundwater levels in the East region are currently below the drought zone 1 curve, lower than at this point during 2018. East region has now been in drought zone 1 since August 2018, having seen a faster decline than the LTA through the summer of 2018 and slight decrease in levels through January 2019. Levels increased through February and March at approximately the same rate as the LTA trend, despite receiving rainfall in March which was in excess of 120% of the LTA. This happened as the effective precipitation for the previous five months was less than 65% of the LTA and consequently, soil moisture deficit (SMD) has been high. This has meant that the rainfall has first needed to satisfy the SMD before contributing to groundwater recharge. April’s rainfall was 26% of the LTA and groundwater levels decreased through the month, in line with the LTA curve.

There are a range of possible scenarios for 2019. An average rainfall scenario (100% of the LTA) would likely see levels remain in drought zone 1 over the summer and stay in this zone as we go into the next recharge period. Lower rainfall scenarios (60% or 80% of the LTA) may see levels approaching drought zone 2 in late summer/autumn 2019.