From - Yorkshire Water Humbercare Sewage Network Analysis July 2008

If the top of this blockage is at or below low tide level it will have no effect on dredging as it is no use dredging below low tide level. In an upland stream this blockage would be a bank of gravel in a straight wide stretch of river just after a bend - does this apply here and if necessary could it be removed?

From - EA Draft River Hull Flood Risk Management Strategy Report - May 2010 Section 4.3.1

Map showing these drains.