Peak streamflow refers to the date in spring when water levels in the river are highest. When water comes and how much is available are important factors for forests and for the humans living downstream of them. Timing of peak streamflow is determined by warming temperatures, depth of the snowpack, and soil moisture going into winter, as well as timing of diversions (when humans move water to a location other than its natural flow).
For this indicator, we look at peak spring streamflow for the year. Peak streamflow typically happens in May or June and is closely tied to snowmelt. The data for this indicator come from US Geological Survey streamflow gauges in your watershed.
Near average: Date of peak streamflow has been near average over the past five years. Forest ecosystems and human communities are well adapted to this timing.
Timing of peak streamflow is indicative of water availability throughout the following spring and summer. It also relates to other forest conditions, including timing of snowmelt and late winter/early spring temperatures. Changes in timing of streamflow can create challenges for agricultural water users, towns, and water recreation, as well as changing availability for plants and animals.
Timing of peak streamflow is highly variable, meaning it changes a great deal from year to year. Over the current existing data record, there has not been a consistent shift toward either earlier or later peak streamflow. However, as climate change continues to warm Colorado, we may see related shifts in snowfall and snowmelt patterns, leading to changes in timing of streamflow. Towns, recreators, and the agricultural community may need to alter timing of their own activities accordingly, while forest plants and animals may be forced to cope with changes in timing of their seasonal activities as well. Individuals like you can help reduce stress from changes in timing and availability of water by avoiding wasting water in your day-to-day life, particularly in dry summers and years with early peak streamflow.