For Thomas Adès, an aquifer is analogous to the way a composer steers a musical impulse. The strength and direction of groundwater, flowing beneath us, is dictated by geology – layers of rock with varying degrees of permeability. So must musical material be channelled through a series of compositional tools: structure, harmony, orchestration and so on. It is from this process that Aquifer gets its title – representing a kind of inverse programme, in which the music informs the subject. Here, Adès enlists the full gamut of his considerable compositional technique to steer, contain and ultimately unleash a musical wave.