block

verb

past tense: blocked; past participle: blocked

1. 1.

   make the movement or flow in (a gutter, downpipe, roof gulley, etc.) difficult or impossible.

   ” the trees block up the gutters and down pipes with leaves”

   • put an obstacle in the way of .

     “the slipped tile, blocking the water travelling to the downpipe”
   • prevent access to or the use of.

     “the blockage prevented the rainwater from accessing the downpipe”
   • restrict the capacity  of the guttering.

     “the debris restricted the capacity of the gutter resulting in rainwater overflowing down the wall”