How can detect submarine in shallow water ?

Hunting for quiet diesel submarines in the shallow waters of the littorals is akin to trying to identify the sound of a single car engine in the din of a major city, he says.

There are variations in the underwater topography, with sand bars, coral reefs and channels. Different depths of water and changing salinity and temperatures alter how sounds propagate. Marine life and merchant shipping also complicate the search by generating ambient noise.

http://www.nationaldefensemagazine.org/archive/2008/April/Pages/AntiSub2301.aspx

maybe:

LCS class, Type 056A

Ka-28

P-8A…..

I think in shallow water can only use the MAD system or Electro-Optical to hunter sub. Because, the sonar system affected almost distracted, by the sound around. radar is sometimes, the submarine often will dive under the surface