Not at all - but thinking of the river I am familiar with, the River Mole, that forms the boundary of our land, dredging would be prohibitively expensive as well as totally pointless!

during the summer the depth to the river surface is over 20 foot, in the winter it regularly breaks it banks - dredging during the winter wouldn't be practical due to depth of water, speed of flow and width of river, at about 25 foot with tight bends.  In any case where would the silt be deposited?  No access by road and the river isn't navigable by anything bigger than a rowing boat.

What would be the point of removing water from the natural flood plain?  If people buy houses at risk of flooding then why should the tax payer pay to protect them?