2025 Ottawa River Spring Freshet Review

Bulletins posted on 2025-07-16 by Ottawa River Regulation Planning Board

Warm weather combined with rain in mid-March triggered early snowmelt across the basin. Principal reservoirs maintained high storage capacity while this initial runoff occurred. A significant snowpack remained in the northern portion of the basin until mid-April, when successive episodes of warm weather and rainfall accelerated melting and spring runoff in this region. The principal reservoirs gradually filled from mid-April to early May, reducing flood impacts along the main stem of the Ottawa River. The combination of early onset conditions and substantial northern snowpack resulted in a prolonged freshet with multiple peaks and substantial total volumes through the spring period.  Water regulation via the reservoirs was key in maintaining conditions along the main stem below major flood levels in most flood vulnerable areas between Mattawa and Montreal.

Find out about other highlights of the spring freshet 2025 in this bulletin.

Read the bulletin >> 2025-Ottawa-River-Spring-Freshet-Review