Figure 4. Seasonal water balances reveal important differences in forest and climate influences upon streamflow among control basins at the four sites. The AND site has the largest and most seasonally variable soil and canopy storage reservoirs as well as large snow reservoirs and a strong summer ET signal from evergreen needleleaf forest, and moisture storage in these reservoirs is synchronized by seasonally varying precipitation, contributing to the greatest observed seasonal differences in streamflow among the four sites. At the opposite extreme, the LUQ site has little seasonal variation in precipitation and ET from evergreen broadleaf forest and virtually constant canopy and soil moisture storage, with near-constant streamflow. A spring maximum snow reservoir at HBR, combined with a summer ET signal from deciduous forest vegetation but little variation in canopy or soil moisture storage, contributes to the second most seasonally variable streamflow signal of the four sites. At CWT, the summer ET signal alone combined with a relatively large soil moisture reservoir and seasonally constant precipitation inputs produces only small seasonal variation in streamflow.
