both first and second creek, both originating in the adelaide hills, run through the suburb. first creek surfaces on the northern side of alnwick terrace, within the marryatville high school grounds, then flows through the grounds and out under the crescent, while second creek passes under hackett terrace at its northern end, flowing through several properties on either side of the road before being canalised. severe floods in november 2005 overflowed both creeks' banks and caused some damage to both mhs and loreto, as well as some houses.