How is Lough Neagh's water quality monitored?
A team of expert scientists from the Northern Ireland Environment Agency’s (NIEA) Freshwater Investigations (FI) team works with colleagues in the Department of Agriculture, Environment and Rural Affairs (DAERA) and the Agri-Food and Biosciences Institute (AFBI), playing an important role in the monitoring of blue-green algae blooms in Lough Neagh.
A Multi-Phase Response to a Growing Threat
In response to the increasing prevalence of blue-green algae, the NIEA team launched a multi-phase investigation beginning in December 2023 – ahead of the implementation of the Lough Neagh Action Plan. The first phase focused on understanding the influence of river inflows on lake conditions. They put in place monitoring equipment at the mouths of the six major rivers which flow into Lough Neagh: Six Mile Water, Maine, Moyola, Ballinderry, Blackwater, and Upper Bann, to track temperature and dissolved oxygen every 30 minutes.
Phase Two began in July 2024 with the launch of advanced monitoring equipment on a buoy at Rea’s Wood, Antrim. This collects live, high-resolution data on water temperature, oxygen levels, conductivity, turbidity, and phycocyanin — a key indicator of blue-green algae. The data helps to track changes in water quality parameters and indicate potentially harmful algal levels in near real-time.
In July 2025, Phase Three saw the expansion of the monitoring network to include two additional buoys: one at Washing Bay near Maghery (South-West of the lough), and another in the Lower Bann River at Toome, just downstream of the sluice gates (North-West outlet). The instrumentation on these buoys provides telemetered temperature, dissolved oxygen, conductivity, turbidity, and blue green - phycocyanin data at 30-minute intervals.
Benefits from the Lough Neagh Monitoring Programme
The data from the monitoring buoys in Lough Neagh has already proved beneficial. For example, dissolved oxygen issues have been identified in the River Blackwater and River Ballinderry and have been subject to further investigation to locate the source and target mitigation.
Meanwhile, phycocyanin readings from the three key monitoring locations on Lough Neagh capture the variability in algal activity, supporting early warnings for bloom development and movement informing actions taken by the Interagency Blue Green Algae Tactical Coordination Group.
Lough Neagh Blue Green Data Viewer
This data is now available to the public via the Lough Neagh digital platform on the DAERA website at Lough Neagh Water Quality Dashboard. Access to this data will empower communities, researchers, and policymakers with the information needed to safeguard Lough Neagh and its surrounding waters.