With dire reports on falling river levels coming in from all over Europe, Portugal has, this far, been spared the anxiety.
All river basins in the mainland, with the exception of the Lima and Mondego basins in the north, showed above-normal water levels at the end of July, according to the National Water Resources Information System (SNIRH).
The Lima river basin was at 51.9% of its volume on the last day of last month, while the Mondego basin was at 74.3% – when the normal levels are 65.3% and 78.2%, respectively.
The Oeste basin had the most water reserves, at 100%, followed by the Mira (94.3%) and Barlavento (86.7%) basins.
According to SNIRH, the basins with the least water were those of the Lima (51.9%), followed by those of the Ave (66%) and the Douro (71%).
Of the 60 monitored reservoirs, 21 have water availability exceeding 80% of their total volume, and at the end of July there were no reservoirs with availability below 40% of their total volume.
Each river basin may contain more than one reservoir.
The June climatological bulletin, prepared by Portuguese Institute of the Sea and the Atmosphere, IPMA, indicated that 61.1% of the territory is experiencing mild drought and 2.7% moderate drought.
The index that measures the amount of water in the soil varies between extreme rainfall and extreme drought classes.
Meteorological drought and hydrological drought are two different states of water scarcity.
Meteorological drought occurs first with a lack of rain, while hydrological drought affects water levels in dams and rivers later.
There is one important point not addressed by Lusa’s article, and it is the health of aquifers (underground sheets of water, many of which have existed like large underground lakes for centuries). These are not doing so well. In fact, they are generally understood to be at unprecedentedly low levels – a dilemma that a winter’s worth of good rain cannot instantly fix. This is why the importance of using water wisely is being constantly impressed on consumers by the authorities.
Source material: LUSA