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3. Flushing Time Scales ( assumes homogeneous tanks)

	Flushing time [days] (ADCP measurements)		Flushing time [days] (dZ/dt measurements, i.e.tidal prism)
	Upwelling period	Calmer period	Upwelling period	Calmer period
Outer Harbour	1.53	1.58	4.01	3.4
Embayment C	1.29	1.01	3.34	2.35
Cell 3	9.45	8.20	7.75	5.10
Cell 2	N/A	N/A	1.18	0.76
Cell 1	N/A	N/A	11.13	8.55

Accuracy : 25-30% due to:

Approximations of vertical velocity profiles
Approximation of cross sections
Measurement errors
Horizontal distribution of velocities
Changes in bathymetry

Volumes have been accurately (0.5%) estimated with GIS tools based on existing bathymetry profiles
The differences are higher during upwelling period suggesting that baroclinic forcing (temperature/density driven currents) have a larger role.

Notes:

In order to understand how fast the water is exchanged, which determines in part the temperature and the water quality of the embayments we calculated the flushing times

The accuracy of the flushing times ranges between 25-30% caused by :

●Approximations of vertical velocity profiles

●Approximation of cross sections

●Measurement errors

●Horizontal distribution of velocities

●In general the calculated flushing times are longer during upwelling events periods suggesting that during that period density driven currents are stronger

Flushing time calculated from tidal prism are in general longer than those calculated though velocity measurement. The difference may be cased by additional exchange produced by density currents (caused by the difference in temperature between the lake water and the warmer embayment water)

The calculations assume an idealized Continuous Stirred-Tank Reactor (CSTR) state of the embayments. In reality for Cell 1 and Cell 3 the flushing times can be shorter because duet to stratification only the epilimnion volume is actively involved in the water exchange.