[Acoustics] RE: Algae Growth Affecting Sontek SW Flow Calculations

[Winslow, Grant]

I'm resending this email out in hopes of getting a response back.  The
first time I sent out, I hadn't received any responses.

Look forward to any feedback!  Thanks in advance!

Regards,

Grant Winslow

> _____________________________________________ 
> From: 	Winslow, Grant  
> Sent:	Monday, February 28, 2005 12:23 PM
> To:	'acoustics at simon.er.usgs.gov'
> Subject:	Algae Growth Affecting Sontek SW Flow Calculations
> 
> I have proposed to install a Sontek SW velocity meter on the floor of
> one of our gunited canals.  However, there was some concern that the
> actual flow within the canal would not be accurately measured during
> periods when there might be heavy buildup of algae within the canal.
> 
> The reasoning was that the cross-sectional area that was originally
> input into the Sontek SW software when the canal was clean, would be
> effectively reduced during periods of heavy algae growth within the
> canal at certain times of the year,  thereby, inaccurately calculating
> a higher flow rate. 
> 
> It is my understanding that the "backwater effects" caused by heavy
> algae growth on the sides of a gunited canal, would result in the
> meter measuring lower velocities and, in turn, calculating lower flows
> at any given stage versus when the canal was free of algae buildup on
> it's sides.  I didn't think that the reduction in the cross-sectional
> area of the canal with heavy algae buildup vs. the cross sectional
> area stored in the Sontek SW software, when the canal was free of
> algae, would be of significance.  Is this not the case?  Or would I
> need to enter a correction factor for the cross sectional area to
> account for this algae buildup in the canal certain times of the year.
> Any feedback greatly appreciated!
> 
> Regards,
> 
> Grant Winslow
> PG&E Hydrographer
> 
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