A watershed is defined as the entire area of land that moves the water it receives into a common waterbody. The Gun Lake Watershed comprises approximately 50 square kilometers of mountain lands on the east side of 2634 m Mount Penrose and the west side of 1244 m Mount Zola that drain into Gun (5.7 km2) and Lajoie Lakes (0.5 km2). Privately owned land forms a large part of the lower elevations of the watershed. Crown owned, merchantable timber lands within the watershed comprise about 26 square kilometres. There are 2 streams flowing into Lajoie Lake, Alder Creek and Penrose Creek. Gun Lake receives water from Lajoie Creek and Walker Creek, with seasonal input from Sumner Creek. The seasonal water volume flowing into both lakes from those streams appear to be significantly less than the comparable seasonal water volume that appears to flow out of Gun Lake and the watershed’s sole exit, Lajoie Creek, at its north end. The difference between incoming stream volumes and out going water volumes, coupled with the short season of ice cover, suggests that ground water flowing all season from Mounts Zola and Penrose comprise a material part of the waters feeding into Gun Lake.