Development and Application of Flow Duration Curves for Stream Restoration

: Stream restoration does not exist as an isolated field of study but instead at the intersection of hydrologic and hydraulic engineering, terrestrial and aquatic ecology, geomorphology, geology, and biogeochemistry. Palmer and Bernhardt (2006) identify the linking of hydrologic processes with ecological outcomes as a starting point for effective, holistic stream restoration design. Accordingly, traditional engineering approaches of quantifying hydrologic processes may be adapted and applied to quantify ecological outcomes (Fischenich and McKay 2011). Poff et al. (1997) identified five critical components of a streamflow hydrograph that regulate ecological process in river ecosystems: magnitude, frequency, duration, timing, and rate of change. Importantly, many of these variables are correlated and care should be taken to avoid redundancy in analyses (Olden and Poff 2003). Quantification of magnitude, frequency, and duration may be at least in part accomplished by a traditional tool of the river engineer, the flow duration curve (FDC).