stˈɑːlsvætnɪt wʌz fˈɔːɹmd ɪnðə lˈeɪt nˈaɪntiːnhˈʌndɹɪd fˈoːɹɾi z baɪ ðə dˈæmɪŋ ʌvðɪ ˌʌpɚ pˈɑːɹts ʌv θɹˈiː ɹˈɪvɚz, stˈɑːlsvætən, ˈɑːlsəndvˌætən, hˈɑːlsɛlvə wˌɪtʃ kɹiːˈeɪɾᵻd ɐ kəntˈɪnjuːəs lˈeɪk əkɹˌɑːs ðə wˈɔːɾɚʃˌɛdz.
Stolsvatnet was formed in the late 1940s by the damming of the upper parts of three rivers, (Stolsvatn, Olsendvatn, Holselva) which created a continuous lake across the watersheds.