the value "b" refers to the costant that a subsatnce would have when damping an osolation. Such as when a device is a attached to a spring, (with the attached device placed in a sunbstance) and the attached device is put in honey the honey would dampen the vibrations more then say if the attached device was placed in water. Therefore the b value is the value refering to the damping constant of the substance used. And it is the b value for water that I am wondering.
I believe that you will find that you cannot specify a single damping coefficient for water. It is much more complex then that, the damping coefficient will be dependent upon the entire dynamical system. Generally this parameter will have to be extracted from your data, not a reference book.