Prior to coming to Boston in 2004 (and sometime afterwards, until I retired) I worked as a design engineer in the field of barriers to prevent flooding and to retain water for marinas etc.
I have been to all the exhibitions and was unable to understand what the Environment Agency (EA) are doing.
I believed, as many Boston residents do, the the idea of the barrier is to protect them from a surge from the Wash/North Sea.
The EA had on its website, now removed, a 24-page document ‘Boston Waterways Link: Witham to South Forty Foot Drain’ provided by their consultant.
As part of my work I acted as a consultant on projects such as this for the EA and other clients and found it revealing.
Having carefully read this document it appears that the following is correct.
The increased protection from the surge comes from raising the banks/walls to seven metres from the present five to six.
The Grand Sluice would continue to be the end of the protection. The walls/banks are to be upgraded to ‘modern standards’.
The lock gates are old, never were designed to resist a surge, and are to be replaced by a modern design. The docks are in private ownership and it is not clear who pays for it. No barrier is required to provide this protection. If the walls and banks are not raised no extra protection will be obtained.
All the proposed changes in the form of a barrier and diversion pipes for the Black Sluice outlet are for what the document says, Boston Waterways Link, and nothing else.
The document does not include the 2007 event when it rained hard, the Grand Sluice could not pass all the water and the river broke its bank at the point under the rail bridge on the tow path between the Witham pub and the Grand Sluice.
A BBC report on the barrier, dated 18/01/10 noted when the barrier is built it would be similar to the Thames Barrier, only smaller (officials said). Just not the case.
It is my opinion that the proposal will cause more flooding, not less. If the barrier were to be placed where the Haven enters the Wash it would give similar protection to Boston that London enjoys from the Thames Barrier and no raising of the walls.
The EA claim that there are environmental issues with the mud flats, but this is difficult to understand as the barrier, like the Thames Barrier, would be open for more than 99 per cent of the time.
David C. J. Matthews