Lake Heney has a surface area of 12.3 km² with the watershed covering 64.8 km². 95% of the watershed is covered with deciduous forest, resulting from logging over the past 30 to 90 years. The deforested areas are essentially composed of farmland (pasture and fodder) often next to the lake or crossed by important tributaries.
The watershed consists of lakes, alluvial plains and hills whose net elevation varies from 50 to 200 metres. The highest points are formed by quartzite crests to the East of Heney Lake and reaching a maximum of 370 metres. The depressions have altitudes of varying from 150 to 160 metres. Apart from Heney Lake, the watershed includes lakes Vert, Noir, Long, Désormeaux, Ruglis, à la Barbue, Chat Sauvage and Partridge, whose surface area totals 5.4 km². The principal lakes of the watershed (Heney, Désormeaux, Vert, Noir, and à la Barbue) are at almost identical altitudes (144 to 145 metres). Lakes à la Barbue, Désormeaux and Noir intercept 60% of the drainage into Heney Lake, playing the role of natural traps for suspended matter and elements of limited solubility such as iron (Fe) and manganese (Mn). Like many other lakes in the Outaouais region, Heney Lake rests on unusually geology. About 50% of the watershed rests on calcareous marbles (CaCO3), dolomitic marbles [(CaMg)(CO3)2]. These two types of marble generally have very low concentrations of other minerals and are also particularly poor in iron, aluminium, sulphur and phosphorus.
The following link is to a custom topographical map centered on Lake Heney is provided by JLC Géomatique who have waved their copyright for the Web site. For copies, contact them at 819-643-1243 or toll free 1-866-301-2212.