Faughan (inactive)

Note: ECN monitoring ceased at this site in 2004 due to health and safety considerations.

Rising on the north-western slopes of the Sperrin Mountains above Claudy in County Londonderry the Faughan flows in a general north-westerly direction augmented by numerous tributaries and eventually discharging to Lough Foyle. There are no significant urban influences until the river flows through the Drumahoe industrial estate. Approximately 40km long, the river has a catchment area of just under 300km². The River Flow Gauging Station at Drumahoe records flow for more than 95% of the catchment upstream of the ECN site located at Mobuoy Bridge.

The geology of the upper reach consists predominantly of thin deposits of peat overlying schists and quartzite from the upper Dalradian period. This results in a typically 'flashy' runoff characteristic. Further downstream, the lithology changes to boulder clay (till) with significant deposits of sands, gravels and alluvium in the river plain. The underlying solid geology varies to include grits and slates with a thin band of Dungiven Limestone. The steep valley slopes and upper reaches have little capacity to store and transmit groundwater, while the lower reach and river plain may be classified as moderately permeable solid aquifers. In particular, the sand and gravel deposits, overlying fractured grits and slates, are vulnerable to surface impacts and form an important source of base river flows.