catchment · Northern Ireland

Lough Neagh

MonitoringOperator: NI Water / MultipleRegulator: DAERA / NIEA

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What do you want to check?

What happened

Lough Neagh's recurring cyanobacterial blooms create the most complex evidence environment in the four markets. The Executive approved a 37-point Action Plan in July 2024. By mid-2025, DAERA reported 23 actions delivered and 14 in progress. Yet severe blooms continued in 2025. The high-value product is a trusted system of record showing what each intervention changed, over what area, against what counterfactual and with what uncertainty. Nutrient-source estimates vary: approximately 56–62% agriculture and 24–36% wastewater. Drinking-water compliance was 99.88% for 2024, but serious taste-and-odour events were recorded in September 2024.

7 events on record from 13 source records.

The evidence starts to differ here

The evidence starts to disagree here

First difference June 1, 2025

Delivery of the action plan and the state of the lake point in different directions.

Latest evidence

  • Fisheries, Aquaculture and Water Environment Bill introduced

    June 22, 2026

  • Four suppliers advance to Phase 2 of blue-green algae innovation pilots

    March 1, 2026

  • OEP opens investigation into DfI, DAERA and Utility Regulator

    November 1, 2025

  • DAERA reports 23 of 37 actions delivered, 14 in progress

    June 1, 2025 · Material change

  • Drinking water compliance reported at 99.88% for 2024

    March 1, 2025

  • Serious taste-and-odour events at Castor Bay and Moyola WTW

    September 15, 2024 · Divergence

What we haven’t found

BioVeracity has not located the following in the public sources reviewed for this place. Absence here is not proof that nothing happened — only that the record is, so far, silent.

  • Nutrient-source percentages vary by model scope and source grouping

    Why it matters: A single headline attribution would be misleading. Competing estimates cannot be reconciled without common model boundary.

    What would resolve it: Model boundary definitions, period, source grouping methodology for each estimate

    Classification: Evidence gap

  • Tributary stations lack continuous nutrient concentration data

    Why it matters: Tributary source-to-lough attribution remains incomplete. Near-real-time load calculation not possible.

    What would resolve it: Paired flow and nutrient concentration data at tributary stations

    Classification: Evidence gap

  • Majority of 724 overflows lack confirmed EDM coverage

    Why it matters: Overflow frequency and duration cannot be independently verified for most locations.

    What would resolve it: Asset-by-asset EDM installation status and data quality records

    Classification: Evidence gap

  • Sediment phosphorus release contribution not quantified

    Why it matters: Short-term lack of ecological response may not prove interventions failed—internal loading may sustain blooms.

    What would resolve it: Quantified sediment phosphorus release estimates and modelling

    Classification: Evidence gap