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

3.4 – Stratification and water-column stability
From the above discussion of DO, temperature and salinity fields in the estuary, it is
clear that stratification plays a primary role in circulation, water residence and water
properties during closure events. Stratification controls vertical mixing, reducing it or
completely suppressing it, and results in observations of deep-water hypoxia, mid-water
hyper-oxic conditions and mid-water hyper-thermal conditions. Stratification is also
evident during open-mouth periods, most notably during neap tides and weaker river
flow. Density of the water during closure (Figure 3.28) shows a vertical difference of
about 20kg/m 3 and sharp stratification approaching 10kg/m 4 throughout the mid/outer
estuary. During high-tide conditions (Figure 3.28), the water column at the mouth is well
mixed while the outer estuary is partially mixed, with stronger stratification observed in
mid-estuary.
Figure 3.28. Density during closure (top) and high tide (bottom). Units are kg/m 3 .
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