River Witham


From Date: 02/08/2021 15:00

To Date: 31/10/2021 17:00 inclusive

Type: Advice

Reason: Information

Is the towpath closed? No

Intersection of

Closest waterway: River Witham

Starts at: Lock 4, Boston Lock

Ends at: Lock 1, Stamp End Lock


Closest waterway: Fossdyke Canal

Starts at: Lock 1, Torksey Lock

Ends at: Lock 1, Torksey Lock


12/10/2021 09:59

Reports this morning indicate that the weed has cleared significantly at the Boston end of the River Witham, aided by the change in weather and continued efforts to flush out beyond the lock gate and sluices.

We are aware that the weed is taking a little while longer to clear on the Fossdyke, particularly near to Burton Waters.

Reports are that the weed is not too thick, however our contractors are focusing on this area today with the weed boat.

05/10/2021 13:22

The news coming from the Boston Lock end of the River Witham that the weed is clearing. Our weed boat contractor usually operate until the end of September, we have extended this to the end of October in an attempt to create as much opportunity for boating as possible whilst the weather allows. 

24/09/2021 09:37

The efforts to tackle the weed on the River Witham continue. The Environment Agency have been on site twice this week flushing weed through their sluice gates. We have continued with two weed cutters to clear as much as possible from the navigation. 

The EA advise they will be revisiting today to attempt more flushing. 

03/09/2021 23:09

An update regarding the weed situation at Boston.

We have been working continuously to try and resolve the problem. Each of us working in the operations team share the frustrations of boaters, businesses and all affected by the weed.

As previously pointed out, we identified the weed is a mix of duckweed and an invasive species called azolla. We have released small bugs called weevils that eat the azolla in order to try and brake up the weed. Unfortunately, weevils do not eat duckweed. 

As some of you have seen, we have added an additional weed boat onto the river and are removing between 300 and 500 loads of weed from the navigation each week.

We continue to flush weed through our own lock at every opportunity.

The sluices and associated booms adjacent to the gate do not belong to Canal and River Trust. They are an Environment agency asset designed to be used for their primary function of flood relief. These sluices can only be operated by the EA as they also monitor water levels and must balance abstractions for use in agriculture.

The EA have been operating the sluices weekly to try to to flush the weed. We are working closely with the EA to seek options to increase the amount of weed flushing that can take place each week. 

25/08/2021 16:05

We continue to work with the EA to operate the sluices at Boston to flush out as much weed as possible. The Environment agency are providing what resource they can to assist when they are on site. Our Lock keeper continues to flush out what he can through the lock.

We are aware of concerns from Anglers regarding conditions for fish in the river with regard to Oxygen levels and our ecology team was on site yesterday taking readings. The oxygen levels are of concern, though regular flushing at the lock does mean they recover quickly. Again we are working with our own fisheries team as well as the EA's and ask that sightings of distressed fish are reported to us with photographs where possible.

We have confirmed that the majority of the weed is in fact duck weed though there is presence of Azolla - an invasive weed. We will be deploying weevils to see if this assists in breaking up the weed, though we know it is only effective on azolla and not duckweed.

We continue to do all we can to resolve this issue.

19/08/2021 12:04

We continue to battle overwhelming levels of Duckweed on the River Witham. We appreciate the restrictions this has on our boating customers and are doing all we can to resolve the problem. This is a naturally occurring issue and we are effectively battling nature itself. This year the conditions appear to be such that duckweed is flourishing and continues to grow and spread rapidly. Our contractors are doing what they can to clear as much as possible, however this is an expensive and time consuming process. 

Our Lock keeper continues to flush as much weed out of Boston lock with the tide and The Environment agency continue to work with us to operate the sluices gates at Boston when resources and tides allow . This is clearing the weed, but brings with it the issue of pulling weed from up stream of the Witham. We share the frustration of boaters and businesses affected by this and assure all that we are not being complacent in tackling the problem.


We continue to battle the dreaded Duckweed on the River. We appreciate the restrictions this has on our boating customers and are doing all we can to resolve the problem. 

The Environment Agency have agreed to operate their sluice gates at Boston to assist in flushing the weed from the river. There will be a slight delay whilst they arrange craft to move the boom (upon which the weed gathers) 

Our Lock keeper continues to flush as much weed out of Boston lock as possible when on site and tides allow.