Chadwick Lakes are a number of dams, pouring into each other, on the island of Malta. The area is locally known as Wied il-Qlejgħa. Their location extends from Qliegħa Valley (Wied il-Qliegħa) in the limits of Mtarfa and Rabat, and extends to Għasel Valley (Wied il-Għasel) in the peripheries of Mosta. It consists of a complex system of well-planned small dams, draining into Speranza Valley, then at Salina Bay, and then into the sea.
The lakes consists of a number of dams constructed by Sir Osbert Chadwick, a British engineer, in the late 19th century. The valley consists of a complex system of well-planned small dams, draining into Wied Speranza and ending at Salina Bay into the sea. The valley provides farmers with water to irrigate their land. Wied il-Qliegħa is only full during the winter months. During this period, the lakes are abundant of life. Biodiversity include of several indigenous plants, insects, tadpoles/frogs and crustaceans.
In February 2009, Matthew Psaila a 19 year old gunner, drowned during an Armed Forces of Malta training exercise in Wied il-Qliegħa. This particular exercise is part of the C Company's training syllabus and had been practiced for several years.
As of 2018, Chadwick Lakes has been a site of particular interest to Biodiversity and Conservation specialists as the presence of alien species of crayfish is putting significant pressure on the local environment via predation and habitat destruction. 
- Morana, Martin (September 2011). Bejn kliem u storja: glossarju enċiklopediku dwar tradizzjonijiet - toponimi - termini storiċi Maltin (in Maltese). Malta: Martin Morana (by author). p. 47. ISBN 978-99957-0-137-6. OCLC 908059040.
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- "Invasion by non-indigenous freshwater decapods of Malta and Sicily, central Mediterranean Sea | Journal of Crustacean Biology | Oxford Academic". Academic.oup.com. Retrieved 2020-02-27.
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