This programme brought about a conjunction of the elements: a new work about the drowning of a village followed by a stirring performance of Stravinsky's Firebird Suite. With John Adams's masterpiece, Harmonium, Stravinsky's Scherzo à la Russe and Barber's Op 12 Essay for Orchestra by way of acclimatisation, this was a long night. Yet it was ultimately all the more satisfying for its engagement with the way that humanity must not only fathom life's physical elements but the metaphysical and metaphorical, too.

For Harmonium, the BBC National Orchestra of Wales was joined by its National Chorus and the Bournemouth Symphony Chorus. While Adams's 1981 score tests the voices sorely, conductor Grant Llewellyn's balancing of the huge vocal and instrumental forces was authoritative and inspirational. In the opening movement, which sets John Donne's Negative Love, the momentum created from the very outset with its single-note pulsing was gradually built up into an exhilarating tidal wave. The contrast with the languid stillness of Adams's setting of Emily Dickinson's Because I Could Not Stop for Death, and the escalating tension through to the climactic elation of the final Wild Nights, was equally potent.

Just as Adams was fired by Wallace Stevens's Harmonium - although only the title was to survive as homage - the Welsh composer Guto Pryderi Puw took the work of the radical poet-priest RS Thomas as the basis for his symphony, Reservoirs. Thomas's poem describes his revulsion at the flooding of Trywerin; Puw compounds the sense of grief at the burying of community and history (so as to give an English city water) by first evoking the simple joy of the unadulterated landscape.

In his musical language, Puw is the most uncompromising of the younger Welsh composers. Here, he handled the orchestra with great assurance and, even if the fragmented quality of the opening of the second section (perhaps mirroring the break-up of a small society) was less compelling, the sense of gradual inundation was achieved to powerful effect. As water lapped eerily against stones, the remembered resonance of Harmonium's ethereal voices seemed to linger in the air.