Projections of climate change impacts on hydrology in the Pacific Northwest region of the USA

The map of change in summer runoff between 1913 and 2003 shows a decrease in in the Olympic Peninsula and The Cascades. This can due to a decrease in precipitation or an increase in evaporation due to warming air temperatures and increasing vapor pressure deficit. It could also be due to increase retention (creation of reservoirs ex).
The next map of change in runoff between 1950 and 2050 shows again a decrease in runoff on the Peninsula and the Cascades north of Seattle.
The next GIS layer showing the proportion of precipitation as snow shows that the decrease in runoff occurs in places where stream are snowfed. A decrease in snowpack would decrease streamflow and runoff. The Climate Impacts Group in Seattle has in fact published maps of the decline in snowpack in Washington state.
Finally, projections of stream temperatures show examples of good conditions (green) for stream water that still persist at high elevations to dangerous (yellow) or even lethal (red, water too warm) for salmonids. The increase in stream temperature can occur due to the loss of shading when riparian vegetation is eliminated but also when streamflow decreases (decrease in the volume of water, greater warming by sunlight) due to for ex. a decrease in snowpack for snowfed streams or reduction in groundwater discharge (cold) due to a decrease in recharge (decrease precipitation) or an increase demand (urbanization, industry).