Normand,

I just asked this same question to a USGS colleague this week (in the context of bathymetry for small streams), his recommendations were:

Hey! Thanks for the info James! I think I'll go for the StreamPro.

Cheers

Norm

Hi Normand,

Looks like you have your answer but thought I would help second it. I haven't used the other two ADCPs mentioned but I use the M9 RiverSurveyor a lot in gravel-bed rivers. It won't work in flows below 0.4 m, and the vertical beam gives poor results if the gravels are moving. You also need to pay for licenses to use the stationary method software or bathymetry software.

Thanks Andrew. I appreciate your view on the question.

If other people also have an opinion on this it would ne nice to hear from them.

Yes TRDI StreamPro with compass and extended depth enabled is best for shallow water

Hello Bergeron,

I have used the Riversurveyor (Sontek). it produces vertical beams. it is good for a long period measurements. but for shallow water i think StreamPro w/ Compass  will be the best. 

Thank you all for your helpful comments and answers.