The water moves in the direction of the concentrated salts, the bitumen acting as a semi-permeable membrane.
ðə wˈɔːɾɚ mˈuːvz ɪnðə dᵻɹˈɛkʃən ʌvðə kˈɑːnsəntɹˌeɪɾᵻd sˈɔlts, ðə bɪtˈuːmɛn ˈæktɪŋ æz ɐ sˈɛmaɪpˈɜːməbəl mˈɛmbɹeɪn.