Canal/waterway cleaner

Canals, at this time of year, seem to be full of rubbish - sandwich packets, drinks bottles, various light industrial trash - but in the summer, without any noticeable cleaning programme, this material disappears. I know where it goes; it all ends up in the dead-end canals where the boats don't go, because the rest of the traffic shunts it along or washes it up in the waves they generate.

I think there should be a periodic programme of canal cleaning, where a boat is taken along every canal at normal speed, with a net dragged behind it which gathers waste. At some pre-determined drag factor, when the waste is affecting the progress of the boat, the net should have a mechanism to seal itself into a bag (I can visualise this but can't quite explain it right now) and drop off, where it will be collected by another barge following behind.It is reasonably feasible to do this for every canal since they don't have many junctions - any junctions either go to another canal or one of these dead ends I mentioned.

Dead ends: These collect waste by the natural waterway flux which I said I'd noticed - it's therefore easier to collect the rubbish in these bits by normal methods of surface dredging. Also, I think the dredging should be done perhaps once a month or two months, but hardly at all in the summer months when there's more traffic. This is because the natural movement of the waterways shuffles the waste into the dead ends then anyway.
General environmental programmes are pretty good at cleaning up the dead ends because they are great habitats for riverbank animals; I just want to extend the principle to the rest of the canals which would then be much more picturesque for those of us who like to go walking and running on them all year.