This astronaut photograph highlights a portion of the Saskatchewan River delta extending into Cedar Lake in the province of Manitoba, Canada. The Saskatchewan River watershed extends from the Rocky Mountains of Alberta through the plains of Saskatchewan and Manitoba to the east. Flooding of the Cedar Lake basin following the construction of the Grand Rapids Dam (to the southeast, not shown) in the 1960s created shallow, muddy lakes and bogs (dark green and blue irregular areas).
The Colorado River is the largest watershed in the southwestern US, emptying into the Salton Trough before reaching the Sea of Cortez. Over the past 2-3 million years, river sediments built a delta that extends from the US-Mexico border for a distance of 87 miles (140 kilometers). However, today the Colorado River delta is undergoing significant erosion and diminishing in size due to the lack of sediment replenishment from upstream sources.