Dredging - How often

[sirweste]

Afternoon,

 

Been struggling on the Grand Union from Slapton to just south of The Three Locks with low levels. Very little change in water depth means I'm grounding which suggests to me that it's due for a dredge.

I didn't expect to have these troubles on the Grand Union to be honest, on smaller less used branches I would be more inclined to expect less frequent maintenance than a main route.

 

What's the frequency of dredging usually?

[larkshall]

I'm guessing really, to answer that question kind of begs how busy it the waterway in question

[jake_crew]

Water levels either side of Cowroast are well down due to the dry weather, exacerbated by leaky gates and the leaky bed in places.

 

But to answer your question - I'd say its rare.

[David Mack]

How much does your boat draw and how much is the level down?

[junior]

 

What's the frequency of dredging usually?

Dunno but I had to get dragged round by a hire boat at the winding hole north of Dutton stop lock this morning. That was embarrassing. So that needs bloody dredging, as does the one to the south of the lock which I couldn't even get half the boat in.

[sirweste]

I'm guessing really, to answer that question kind of begs how busy it the waterway in question

 

I didn't quite make it clear perhaps.

My question was aimed at the stretch of Grand Union I'm currently on, but that said if people know the planned frequency of other sections that might shed some light on it too.

How much does your boat draw and how much is the level down?

 

I don't know the answer to either of these, though it's not really relevent to the question posed.

Dunno but I had to get dragged round by a hire boat at the winding hole north of Dutton stop lock this morning. That was embarrassing.

[David Mack]

I don't know the answer to either of these, though it's not really relevent to the question posed.

 

It is. I came through there a couple of weeks ago on a boat drawing 3 ft, with levels close to normal and had no problems with depth at all. So if, for example your boat draws 2 ft 6 ins and the level is less than 6 ins down, but you are having problems, I would suggest something other than a lack of dredging may be the cause.

[sirweste]

It is. I came through there a couple of weeks ago on a boat drawing 3 ft, with levels close to normal and had no problems with depth at all. So if, for example your boat draws 2 ft 6 ins and the level is less than 6 ins down, but you are having problems, I would suggest something other than a lack of dredging may be the cause.

 

Nah pal it's not. I'm not really interested in the cause, I doin't think there's out I can do that will have an impact on that. Simply interested in the usual dredging frequency.

[David Mack]

 

Nah pal it's not. I'm not really interested in the cause, I doin't think there's out I can do that will have an impact on that. Simply interested in the usual dredging frequency.

CRT's Annual Report for 2014/15 says they "undertook dredging on 50 miles of waterway". Since they are responsible for some 2000 miles that suggest on average dredging takes place every 40 years.

[andy3196]

https://canalrivertrust.org.uk/our-work/dredgingmay be of interest

[Stedman II]

Dredging won't fix the problem if the issue is lack of water! Last year we went up the Perry Barr flight. Most of the intermediate pounds above lock 5 were low, some so low you might have tried to walk across. No amount of dredging was ever going to fix that problem. More water was needed, not a bigger hole in the ground.

[sirweste]

CRT's Annual Report for 2014/15 says they "undertook dredging on 50 miles of waterway". Since they are responsible for some 2000 miles that suggest on average dredging takes place every 40 years.

https://canalrivertrust.org.uk/our-work/dredgingmay be of interest

 

It is! Cheers, no idea how my googling missed that, bad key words on my part obviously.

 

£10.2 million to be spent dredging in 4 years! blimey

[Pluto]

The figures I have for the L&LC suggest that around 1900 they were removing 1000 tons per week or over 50,000 tons per annum, and that was for one canal. Spot dredging use to take place at bridge holes, as that is where rubbish tends to end up. By dredging there regularly, rubbish elsewhere along the canal tended to move towards the bridge hole helped by the movement of boats, and the widening after the bridge allowed rubbish to drop out of suspension.

[MoominPapa]

rubbish elsewhere along the canal tended to move towards the bridge hole helped by the movement of boats, and the widening after the bridge allowed rubbish to drop out of suspension.

On the Macclesfield, it's all moved to bridge 20, it would seem. We draw 2' 10" and had to drag the boat through that one with ropes. (In both directions, three times. Don't ask.)

 

MP.

[sirweste]

The figures I have for the L&LC suggest that around 1900 they were removing 1000 tons per week or over 50,000 tons per annum, and that was for one canal. Spot dredging use to take place at bridge holes, as that is where rubbish tends to end up. By dredging there regularly, rubbish elsewhere along the canal tended to move towards the bridge hole helped by the movement of boats, and the widening after the bridge allowed rubbish to drop out of suspension.

 

Interesting, cheers

[matty40s]

They have " dredged" the Soar and the Leicester Line in the last 6 months.

Unfortunately, this doesn't mean they have dredged it all, just some bits. Missing out other bits which have been problem areas for years.

Below Ratcliffe/Zouch, Bishops Meadow and Town Lock on the Loughborough section, cossingto , Junction and Thurmaston/Birstall locks are all still full of silt ,branches and crap which do not allow you to select reverse and stop properly.

The section from Kilby Bridge to Foxton is still painfully shallow and many sections of the Summit have not been touched,,just select areas.

[GUMPY]

The pound between Slapton and Church has been bad for years so long that I can't remember at a guess about 12....

There used to be a lot of dredging on GU south, in the days when BW could put the dredgings on adjaent fields, alas no more its all hazardous waste now!

[AMModels]

The pound between Slapton and Church has been bad for years so long that I can't remember at a guess about 12....

There used to be a lot of dredging on GU south, in the days when BW could put the dredgings on adjaent fields, alas no more its all hazardous waste now!

Some areas on the BCN I can understand and other more industrial places but why has all dredging spoil been so labelled? I remember 30 years ago when they were repiling the banks on the shroppie they backfilled with dredge waste and it looks pretty green these days!

[GUMPY]

Some areas on the BCN I can understand and other more industrial places but why has all dredging spoil been so labelled? I remember 30 years ago when they were repiling the banks on the shroppie they backfilled with dredge waste and it looks pretty green these days!

That was the way to do it, meant the towpath was impassable for a few months now they just put those stupid environmental hessian sausages down to protect the bank and do nothing else.

Personally piled edges backfilled is the way I like it to be, makes mooring easy.

[matty40s]

Some areas on the BCN I can understand and other more industrial places but why has all dredging spoil been so labelled? I remember 30 years ago when they were repiling the banks on the shroppie they backfilled with dredge waste and it looks pretty green these days!

most of the Leicester Line dredging has been backfilled to the offside or put into fields near Crick.

[David Mack]

There used to be a lot of dredging on GU south, in the days when BW could put the dredgings on adjaent fields, alas no more its all hazardous waste now!

Not quite. Its all potentially hazardous waste. So in recent years BW/CRT have had to take extensive samples and get them tested to work out what treatment and disposal technique are appropriate for dredgings from a particular location.

[Allan(nb Albert)]

Afternoon,

 

Been struggling on the Grand Union from Slapton to just south of The Three Locks with low levels. Very little change in water depth means I'm grounding which suggests to me that it's due for a dredge.

I didn't expect to have these troubles on the Grand Union to be honest, on smaller less used branches I would be more inclined to expect less frequent maintenance than a main route.

 

What's the frequency of dredging usually?

CaRT say, on average, a 'just dredged' urban canal will not need dredging for another 40 years. With rural canals its every 25 years. Obviously these are average figures and do not include spot dredging that needs to take place more often.

 

 

The figures I have for the L&LC suggest that around 1900 they were removing 1000 tons per week or over 50,000 tons per annum, and that was for one canal. Spot dredging use to take place at bridge holes, as that is where rubbish tends to end up. By dredging there regularly, rubbish elsewhere along the canal tended to move towards the bridge hole helped by the movement of boats, and the widening after the bridge allowed rubbish to drop out of suspension.

 

The figure for CaRTs 2,000 miles of waterways in 2014/15 was 130,000 tonnes (i.e 143,000 tons).

[larkshall]

Water levels either side of Cowroast are well down due to the dry weather, exacerbated by leaky gates and the leaky bed in places.

 

But to answer your question - I'd say its rare.

Dry? You are joking aren't you?

[fladda]

nb Syrinx ran aground in what should be/used to be the main channel on the GU main line in this area, aproaching a bridge hole. Draught 2'6. Level no more than 2" off the weir. There was extensive offside bank erosion most of the way along here caused my motor boats going to fast etc. This was near Slapton or Church lock.

 

The depth on the Leicester section was probably the best I've experienced in 25 years, between the new marina at Yelvertoft and the big hole in the ground at North Kilworth. The section beyond Husband's Bosworth tunnel remains as shallow as ever as far as about bridge 48.

 

35 years ago the GU main line was lovely and deep, whereas the Leicester line was a shallow ditch. Situation has partly reversed now.

 

Ralph

[Tuscan]

I agree we had to get pulled off the bottom just below church lock earlier this year and struggled below Slapton. However the sticking points on the Leicester section have been largely removed.