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Notes:
Example of hydrographs and temperature profiles from two different watersheds within the Yakima basin. The Upper Yakima, with a relatively high and constant hydrograph and cooler temperatures through the summer, supports a predominantly resident population. On the other hand, flows in Toppenish Creek decline dramatically from May through September coincident with warmer stream temperatures, and supports a predominantly anadromous population. This dramatic contrast in flow regimes suggests that substantial declines in flow during a key time period (namely summer) plays an important role in determining whether a river will support resident or anadromous O. mykiss.