Great Howe carries the remains of a surveying pillar on its eastern flank. This unusual stone and concrete construction is cleft at the top to provide a sight line and was originally surrounded by a wooden frame, now decayed. This is one of four such pillars built during the construction of the Haweswater aqueduct. Below Branstree, Tarn Crag and Great Howe is the first section of the pipeline carrying water from the reservoir toward Manchester. The tunnel, some 1,000 ft below Great Howe, required 250 tons of gelignite for blasting, and when constructed in the 1930s was the longest such pipeline in Britain. It emerges into Longsleddale below the southern end of Great Howe, where the spoil can still be seen.