Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
The valley in a dream indicates travel, a righteous deed, or hardship. Crossing it indicates salvation from worry. Running in it indicates wading into strife.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
The valley indicates a generous or a stingy man, depending on its state. A green valley indicates a righteous deed, and a dry one indicates a false deed.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
The valley is interpreted as the king or a great man. Descending into it indicates drawing close to the ruler.