The valley of the Wiese, which drains a catchment of 455 square kilometres, is called the "Wiesental" or Wiese Valley; it is oriented roughly towards the south-west. Its largest tributary is the Little Wiese ("Kleine Wiese") which approaches from the north. The right-hand Rhine tributary of the Wiese and the left-hand Rhine tributaries of the Birsig, which discharges into the Rhine at the Basle port of Schifflände, and the "Mühlebach", which flows under the Dreirosen Bridge, are the three biggest Upper Rhine tributaries on Swiss soil.