Hi all,

The winter and early spring saw flows that were always below normal and usually only about half of the seasonal norm. That changed starting on 10 April when flows began to rapidly increase. By the time of sampling 19 April, flows peaked at nearly twice the seasonal norm. Dumping that much freshwater into a really salty estuary caused very strong salinity based stratification with surface to bottom salinity differences of ~15 in the upper estuary from station 30 to station 120 and ~10 further downstream. Bottom waters were cool (< 15 C) and certainly the low temperatures helped prevent bottom water hypoxia. High turbidity (>10 NTU) flood water penetrated downstream to station 60 and turbidity was < 5 NTU throughout the rest of the estuary. A large mid-estuary chlorophyll maximum (> 20 ug/L) was observed from station 60 to 140 and was concentrated vertically just above the pycnocline at ~1.5 m depth. Microscopic examination of station 100 surface water revealed that small solitary centric diatoms and chain-forming centric diatoms were the dominant taxa. There was a relatively high concentration (~1000 cells/mL) of the toxic dinoflagellate, Karlodinium veneficum. Although 1000 cells/mL is higher than normal, Karlodinium doesn’t usually cause fish kills until the concentrations reach about 10,000 cells/mL.