35% of pollution incidents at the River Quoile attributed to NI Water
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35% of pollution incidents at the River Quoile attributed to NI Water

Date: 27 April 2023

Category: General News

Read: 5min Read

Pictured (light green blotches) are algae blooms on the River Quoile in September 2022, located between the Waste Water Treatment Plant and Inch Abbey in Downpatrick.

Excess nitrogen and phosphorus in rivers (from insecticides, pesticides, soil erosion, sewage, storm water or fertilizers for example) can cause an overgrowth of algae. The overgrowth can deplete oxygen and block sunlight from underwater plants and fish, causing them to die. 


Northern Ireland Environment Agency (NIEA) has identified and categorised water pollution incidents at the River Quoile Local Management Area (LMA) between 2012 – 2022. These were attributed to 6 sources: NI Water, domestic, farm, transport, industry or other (figure 1).

The largest number of pollution incidents from a single source are attributed to NI Water  Р67 out of 188 incidents (35%).

Domestic households are identified next as being responsible for 18% of incidents, farms as 13%, ‘other’ as 13%, industry as 3% and transport as 0.5%.

When the Clean the Quoile group drilled down into the ‘Other’ category (figure 2), which accounts for 50 out of the 188 pollution incidents, it was revealed that sewage and suspended solids are the categories of pollution in 22 of the 50 incidents (12%).

NIEA did not attribute ‘Other’ to any one sector.


Figure 1: Source of pollution incidents between 2012 – 2022.


Figure 2: Categories of pollution identified within the ‘Other’ category referenced in figure 1.



Meeting with NI Water, March 2023

Representatives from the Clean the Quoile campaign recently met with senior figures from NI Water at the Waste Water Treatment Plant in Downpatrick, to discuss the above figures. We also wanted to understand how the Plant operates and how sewage from the Downpatrick area is treated and processed there. Members from DEA Downpatrick also joined us.

NI Water has earmarked investment at the Downpatrick Plant, to improve capacity and water treatment quality. They expect this to start in 2025.

We raised a number of questions with the NI Water team around Combined Sewage Overflows (CSO) in the town. We await responses from NI Water and NIEA to our questions.

Clean the Quoile agreed to carry out additional sludge testing near the Treatment Plant to clarify pollutants in the water.

We agreed to meet with NI Water again once all results are collated.