Snowpack, Watersheds and Climate Change

This month, we're addressing where water comes from and where it goes once it goes down the drain.

In the northwest, river basins are where  most of our water is "stored", rather than man-made reservoirs prevalent elsewhere in the U.S. The amount of snow that falls in the winter and the rate of thaw in spring determines how much water will be available when demand for water increases in the summer months.

Climactic variations and changes have a huge impact on water in this area.

From the University of Washington:

The amount of snow that collects in the mountains is sensitive to both precipitation and temperature. Dry winter weather and warm spring temperatures - a more common occurrence during warm phase El Niño/Southern Oscillation (ENSO) events or a warm phase Pacific Decadal Oscillation (PDO) - lead to lower springtime snowpack and streamflow during spring and summer in snowmelt-driven rivers. As a result, flooding is less likely and drought more likely, during warm phase ENSO (El Niño) and PDO.

Click here to access a University of Washington presentation by Mark T Stoeling, Mark Albright and Cliff Mass called A Look at the past 75 years of Snowpack in the Cascades, using a Streamflow-Based Proxy for Snowpack.

This presentation discusses water balance as a result of the following factors:

• precipitation
• evaporation
• runoff
• change in soil moisture
• change in snowpack