Hydrography of the Russian River Estuary - Sonoma County Water ...

Figure 3.8. Observed flow losses during spring closure events. Dashed line represents
25-hour moving average of Pt. Reyes levels.
It is interesting to note that water level in the estuary may asymptote to a steady level as
increased losses due to seepage match steady river inflow, e.g., at the end of the
September 2008 event and at the end of the September-October 2009 event. This is not
observed in the other events, when inflows are larger. Another phenomenon appearing
in the 2009 event and also in the August-September 2000 event is a leveling off of the
flow loss term over time (or with elevated water level).
While understanding the observed stage-discharge relation (Figure 3.5) and specific
events (Figures 3.7 and 3.8) needs further attention, the lower bound on a decade of
empirical results (Figure 3.5; Equation 5) provides a sound basis for operational
estimates of minimum water loss rates for given water level elevations.
3.2 – Tidal and diurnal currents
Observed currents are dominated by strong tidal flows throughout the water column
when the mouth is open and by weak wind-driven flows near-surface when the mouth is
closed. Owing to instrument malfunction, data are only available from Paddyʼs Rock
during open periods dominated by tidal flows whereas for much of the time that the
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