Issue date: 27 July 2010
IWA approached one of its supportive MPs in the House of Commons, Mr David Heyes, MP for Ashton under Lyne to determine the trend for dredging of the network undertaken specifically by British Waterways, and also to inquire if any additional details were available for the Environment Agency.
In seeking this information, as part of its SOS campaign to ensure adequate fundig for the waterways, IWA was attempting to determine if the condition of the waterways was improving, being maintained in a steady state, or in-fact; possibly deteriorating from the point of view of boaters, i.e. is there enough depth of water for navigation; in as much as the cuts in grant in aid might be affecting the amount of dredging being able to be undertaken, both in terms of ‘amount’ dredged and cost incurred.
In answer to a series of detailed questions the Waterways Minister gave the following information:
British Waterways currently has plans to dredge between 30 kilometres (km) and 40 km of its waterways during 2010-11. This will take place at 18 locations, at an estimated cost of £4.5 million.
The Environment Agency plans to dredge a number of sites across its navigations in 2010-11; these will cover an equivalent length of 5 kms. Due to the fact that nearly all of the Environment Agency's navigations are heavily modified natural watercourses, with high flows naturally removing or re-profiling shoals and silt deposits, this greatly reduces the need for the agency to dredge extensive lengths of waterway.
British Waterways estimates that it has dredged the following lengths of waterways for each of the past 10 years:
The Environment Agency does not maintain detailed records on the length of navigation dredging it has undertaken. However, it estimates that it has dredged a length of waterway equivalent to 5km per year, across its waterways over each of the past 10 years.
British Waterways estimates that 291 kilometres (km) of their canals and rivers require dredging, and are prioritised accordingly out of the total of 3,283 km for which they are responsible.
The Environment Agency considers that the current dredging operations of around 5km per year meets the requirements of its navigations, and believes that this level best balances the cost/benefit for navigation with the needs of the environment.
British Waterways estimates that it has removed the following volumes of materials from its waterways in each of the past 10 years:
Volume cubic metres
The Environment Agency estimates that on average it dredges some 50,000 cubic metres of material from its navigations per year. Some of this material is not removed, but is re-distributed to other parts of the river bed within key sites.
IWA asked supplimentary questions of BW to assertain how much waterway was in need of dredging for the period shown 2000-2010. in order to determine if the situation of siltation was increasing or decreasing or being 'maintained'
We recieved information for the three years as shown .
Year Lengths with surveys km Lengths needing dredging km
2008 3155 338
2009 3236 318
2010 3283 291
It is clear from the figures that whilst on the surface matters may or may not be being maintained at a steady state, there has been a distinct tailing off of dredging, which inevitably will affect the ability for navigation, with 291 km requiring dredging and expenditure available to only dredge 30-40 km – or 13% of the system.