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INSIGHT: The rising tide of pollution and sewage spillage

INSIGHT: The rising tide of pollution and sewage spillage

Thursday 29 July 2021

INSIGHT: The rising tide of pollution and sewage spillage

Thursday 29 July 2021


Waste and water pollution incidents in Jersey have risen 50% over five years, while sewage spillages are also going up.

Express plumbed the depths of Environmental Health and Infrastructure records as part of a deep dive into the murky issue...

According to statistics from the Environmental Protection Team released under the Freedom of Information Law, water pollution incidents went from 146 in 2016 to 215 in 2020.

The number is already at 128 for 2021.

Over a 10-year period, St. Helier suffered the most pollution incidents, with 60 recorded in 2020 - a 55% rise over five years.

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Pictured: Tankers are often used to clear up and discharge sewage spillage in other locations with more room.

According to Government, each of these incidents had a different level of impact - ranging from “no impact detected" to some deemed "serious."

Types of pollution

On a domestic level, there appear to have been relatively few incidents, with Environmental Health only reporting 14 incidents of domestic water supply contamination since 2014.

Indeed, most of their records for 'domestic pollution' during that period relate to noise - which makes up more than 1,000 complaints.

However, there were also 60 water quality advice incidents, 29 drainage incidents, 12 incidents involving a pond, pool or ditch, and two incidents of contaminated land.

Parishes ranked by pollution

Since 2011, there have been 1,695 reported incidents of waste incidents and water pollution across the island.

St. Helier again takes the lead again across the decade, accounting for one in five incidents. 

Weighbridge.jpg

Pictured: The most sewage spillages since 2018 have come from the pumping station at St. Helier's Weighbridge.

This is nearly double the number experienced by St. Brelade, next in the rankings.

Looking across the 10 years, the total numbers for the Parishes were...

1. St. Helier - 356 incidents
2. St. Brelade - 188 incidents
3. St. Saviour - 159 incidents
4. Trinity - 151 incidents
5. St. Peter - 149 incidents
6. St. Lawrence - 138 incidents
7. St. Ouen - 122 incidents
8. Grouville - 101 incidents
8. St. Martin - 101 incidents
9. St. John - 91 incidents
10. St. Clement - 88 incidents
11. St. Mary - 40 incidents
12. Unknown (not enough info given but incident recorded anyway) - seven incidents
13. N/A (incidents offshore) - four incidents

Sewage spillage events

Meanwhile, sewage spillages within the island’s infrastructure also appear to be in the rise.

A separate request under the Freedom of Information Law by Express has revealed that incidents of sewer spillage from Jersey's pumping stations have been rising year-on-year since 2018 - more than tripling from 23 cases in 2018 to 101 cases in 2020.

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Pictured: Records of spillage have gone up from 23 to 101 cases since 2018.

The most affected areas were St. Helier’s Weighbridge, which suffered 83 spillages, the Trinity stations (44) and Les Ruisseaux (39).

Causes of these spills largely appear to be weather-related.

Of the 292 incidents recorded over the past four years, 93% were caused by either rain alone, or rain combined with other circumstances.

The Government said that its systems are “designed to spill on heavy rainfall events where combined sewers get overloaded. When this occurs the spills are significantly diluted. 

“All sewer systems are designed to do this in extreme events.”

Cleaning up

Duncan Berry, Head of Liquid Waste Management at IHE, told Express that over the winter of 2020, over 5 million litres of liquid waste had been transported due to heavy rainfall. 

“With the high rainfall levels, the water table around the Island has got higher,” he explained. 

“This… led to clean water finding its way into our foul sewer network, which has caused some of our pumping stations to have high levels, even though they are pumping as fast as they can.

“Tankers have been visiting various pumping stations around the Island where we are getting high levels and emptying the contents into parts of the network where there is capacity.”

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CLICK TO ENLARGE: The Infrastructure Department's telemetry system, which monitors the Island's 110 liquid waste pumping stations.

A common way of handling spillage incidents is to use a tanker and a molex pump to rebalance the levels, and dispose of the waste at other sites - 121 incidents since 2018 saw officers respond with this method.

Other sewage spillage causes

The remaining 7% of causes for the spillages varies, with all being rare occurrences where there was not some factor of rain involved. 

These include a 2018 incident at La Pulente, where there was a single case of an electrical supply failing, five cases of water ingress, and a brook at La Chasse spilling into the station.

On 25 June last year, there was a thunderstorm which hit five stations, with three being unable to be controlled.

Then on 11 November, a storm surge also meant the Rozel 1 station’s covers were uncontrollably covered by the sea.

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