How do I avoid confusing Spelga Dam with Silent Valley when planning a drive?

Spelga Dam and Silent Valley are different Mourne Mountain reservoirs with different access roads.

Silent Valley’s public vehicle entrance is on Head Road near Kilkeel; Spelga is an upland road destination reached from the Hilltown and mountain road network. A satnav search for “Mourne reservoir” is not precise enough. Choose the named site, check that the access road is open and avoid assuming that a car park at one reservoir gives walking access to the other.