A prolonged dry spell on Lundy, a small island in the Bristol Channel off the north Devon coast, has left water supplies critically low. The island has received no significant rainfall since the start of May, according to the Guardian Environment. The shortage has forced managers to restrict visitor numbers and to ask residents to take short showers and avoid flushing toilets. Discussions have also taken place about a possible evacuation of the 28 people who live on the island.
The situation shows how islands and isolated communities can be particularly exposed to drought because they cannot easily pipe in water from mainland reservoirs. On Lundy, the sky has often stayed clear even as rain fell on nearby north Devon and Wales, leaving local storage to shrink. The island's water infrastructure is under severe strain, and conservation measures are now a daily reality for residents.
Postcode elevation data
| District | Post town | Region | Avg elevation |
|---|---|---|---|
| EN77 | Waltham Cross | 0m | |
| GY1 | 0m | ||
| GY2 | 0m | ||
| GY3 | 0m | ||
| GY4 | 0m | ||
| GY5 | 0m | ||
| GY6 | 0m | ||
| GY7 | 0m | ||
| GY8 | 0m | ||
| GY9 | 0m |
Why a sea-level district matters in a drought
The postcode data presented here does not cover Lundy itself, but it does provide a directly relevant example for thinking about water risk. The lowest-lying postcode district in the dataset is EN77, which covers Waltham Cross. The district has an average elevation of 0 metres above sea level, and its peak elevation is also 0 metres. In other words, every point within EN77 sits at exactly sea level.
A district at sea level with no higher ground faces a different set of water challenges from an island like Lundy. While Lundy is short of rainfall, a zero-elevation district can be vulnerable to saltwater intrusion into freshwater sources and to drainage difficulties because there is no natural gradient to help move water away. The data does not tell us about rainfall or reservoir levels in EN77, but it does show that the district has no altitude to buffer against coastal water pressures.
For communities concerned about drought, seeing an entire postcode district recorded at the same elevation, with no variation between average and peak, is a useful reminder that water vulnerability is not only about rainfall. Low-lying terrain can shape how water is stored, how it drains and how it interacts with the sea. EN77 is just one example, and other districts in the wider dataset may show very different elevation profiles, but this single case highlights the extremes that postcode data can capture.
The data behind this
The elevation figures for EN77 (Waltham Cross) come from Postcodes UK, the postcode data site. The table above shows the lowest-lying district in the dataset, with an average and peak elevation of 0 metres above sea level.
In response to reporting by Guardian Environment. Analysis and figures by Postcodes UK.