Figure 4.1 An illustration of the challenges of managing water supply in a reservoir in Nunavut. The upper panel indicates total water storage in a reservoir throughout the year. The lower panel shows a typical river runoff hydrograph. Most of the water is available during the spring snowmelt period, but consumption in a community is relatively constant throughout the year. To maintain adequate water supply for the entire winter period, then, water managers need to consider augmenting water supply during the spring snowmelt period (to yield the greater reservoir quantities indicated by the dashed line). Summer rainfall alone is rarely adequate to accomplish a year-round supply and is, moreover, unpredictable. (Source: S. Lamoureux)