The timing of alterations to instream flows can have additional impacts on aquatic systems, beyond simply modifying the amount of habitat available. Many components of life history timing, such as migration cues, or breeding cycles, are affected by the timing of fluctuations in instream flows. A common approach to analyzing these effects is an office-based analysis to compare habitat and flow conditions under unimpaired and regulated flow scenarios. Differences in hydrographs of synthesized unimpaired vs. regulated flow can be analyzed for daily average flows for the entire water year, and also for the time periods that correspond to specific life stages (e.g., incubation, fry development, migration, spawning). As a result, temperature and flow data can be plotted to correspond to these life stages. This analysis of average daily flow and temperature fluctuations under synthesized unimpaired and regulated hydrology can be used to indicate higher and lower potential for impacts on life history events, such as stranding of fry, desiccation of incubating eggs, or migration cues.
