Wied il-Miżieb was once used as a quarry. After having extracted the limestone the excavated pits were filled with soil and used as agricultural land, making this valley an important agricultural area.

Today, Wied il-Miżieb is a small dry valley hewn in coralline limestone and characterised by a seasonal watercourse.

This valley is especially important because Malta’s largest known population of the national tree, the sandarac gum tree (siġra ta’ l-għargħar) is found here. The valley sides are covered by garigue and steppic communities which house a number of rare, threatened and endemic species, such as the shrubby kidney-vetch, the Maltese spurge, wild thyme, and Mediterranean heath. Fauna in the area include the Maghrebian Mouse-eared bat, the soprano pipistrelle and the endemic swallowtail butterfly.

This Natura 2000 site will be subject to the preparation of a management plan and/or legislation in the near future, as part of an EU- funded project that Mepa is undertaking for the management planning all the terrestrial Natura 2000 sites of the Maltese islands.