Environmental Facts & Figures


Surface Area of Lough 383km²
Average depth 8.9m
Maximum depth 30m
Volume 3.45 x 10⁹ m²
Length of shoreline approximately 125km
Maximum length 30.5km (SW-NE)
Maximum width 12.1km (W-E)

Total Lough Neagh Catchment 5750km²
LN Catchment (NI) 4450km² (31% of Northern Ireland)
LN Catchment (ROI) 390km²
LB Catchment 910km²
Total LN & LB Catchment (NI) 5360km² (38% of Northern Ireland)
Status: Hypertrophic – 145 micrograms phosphorus per litre
Rivers Inflowing:
Blackwater, Ballinderry, Moyola, Six Mile Water, Main and Upper Bann are major tributaries, Glenavy and Crumlin are minor tributaries
River Outflowing:
Lower Bann (reaching the sea at Portstewart)
Drainage schemes:
McMahon Scheme (began 1847-1858) lowered water level by 0.76m.
Shepherd Scheme (1930-1942) plus 1952 and 1959 Schemes lowered average water levels by 1.26m.
Average-to-average lowering over 160 years = 2.02m.
Environmental listings:
Area of Scientific Interest (1965) re-designated ASSI (1992)
Ramsar Site from 1976
Special Protection Area (from 1998)