A noun in the Qenya Lexicon of the 1910s given as ᴱQ. tampo “a well”, derived from the root ᴱ√TṂPṂ “build”; Tolkien considered transferring the word to ᴱ√TAPA “✱stretch” (QL/93). This word also appeared in the Poetic and Mythological Words of Eldarissa (PME/93).
Neo-Quenya: I think ᴺQ. tampo “well” might be salvaged in Neo-Quenya as a derivative of √TAM “construct”; it is used this way in Helge Fauskanger’s NQNT (NQNT).
A noun appearing as ᴱQ. qelu “well, spring, source” in the Qenya Lexicon of the 1910s, derived from the root ᴱ√QEL+U, a variant of ᴱ√KELU (QL/76). It also appeared with the gloss “well, spring” in the Poetic and Mythological Words of Eldarissa (PME/76).
Neo-Quenya: Related words ᴱQ. qelume “source, origin” and ᴱQ. qeluva “original” indicate this word could be used for the “source” of things beyond just water. As such, I think this word might be salvaged in Neo-Quenya as ᴺQ. celu “source, origin”, from the later root √KELU. The form quel- can’t be retained, as this means “fade” in Tolkien’s later writings, and the abstract form celumë can’t be used, as this means “flowing”.