To ask the Minister of Agriculture, Environment and Rural Affairs what recent assessment he has made of (i) the level of pollution in the Three Mile Water River; and (ii) the impact of that pollution on aquatic life.

(i) The Northern Ireland Environment Agency (NIEA), within my Department, monitors all rivers in NI under the requirements of water protection legislation to assess water quality status for classification.

In 2018, the Three Mile Water River was assessed as overall Moderate status with Soluble Reactive Phosphorus (SRP), Diatoms (microscopic plants) and Aquatic Invertebrates all being assessed as Moderate status.

In the most recent assessment carried out in the 2021 classification, the Three Mile Water River remained at Moderate status with both Phosphorus and Diatoms again assessed as Moderate Status. Invertebrate status had improved to Good status.

There were no exceedances of any chemicals monitored in the Three Mile Water in 2015 or 2018.

NIEA is also responsible for investigating, under the Water (NI) Order 1999, reports of water pollution, for regulating discharges to waterways and underground strata and for initiating enforcement action where appropriate.

There have been a number of confirmed pollution incidents in the Three Mile Water River over the period 2016 to 2021. The majority of these have been assessed as low severity. There were two Medium Severity Incidents in 2017, one related to overflow from a blocked sewer that impacted a minor tributary of the Three Mile Water in the New Mossley Estate. This took a number of days for Northern Ireland Water Ltd to clear due to the need for civil works to be carried out as tree roots had grown into and blocked the sewer. The second Medium Severity Incident in 2017 related to the discharge of suspended solids from private civil works in the Rea Hill Road area. A Warning Letter, issued in respect of the Water (NI) Order 1999, was issued to the polluter identified in the latter case.

Two Medium Severity Incidents also occurred in 2021, on 31 May and 26 August 2021.

(ii) The high levels of phosphorus are impacting on aquatic life (Diatoms) in the river and my Department will be investigating the source of this nutrient pressure.

Neither of the 2017 Medium Severity Incidents had any recorded impact on the fishery in the catchment, and there was no longer term impact on water quality identified.

The two 2021 Medium severity Incidents both resulted in Major fish kills. NIEA is following a definite line of enquiry in respect of these two events and enforcement procedures remain live at this time. NIEA treat all aspects of a live and ongoing case as if ‘sub judice’, until the necessary enforcement actions are completed, therefore, no further details of the investigation can be released at this time.