Somerset’s 20 Year Flood Plan is Published

Flooding on Northmoor

Flooding on Northmoor

The Somerset Levels and Moors Flood Action Plan has been produced, as requested by the Secretary of State for Environment six weeks ago. I would like to congratulate everyone involved for pulling together a comprehensive plan setting out the future management of the Levels and Moors in such short order. Along with other Members, I received a briefing from senior officers and Cabinet Members yesterday giving the opportunity to examine the plan and ask questions.

While the Plan overall appears to be a big step in the right direction, I have asked the following questions: –
The Plan refers variously to the need to install a barrier/sluice/barrage on the River Parrett. We need clarity about what is proposed here as the terms seem to be used interchangeably when they in fact refer to very different things, as defined as follows: –

Sluice – a sliding gate to control the flow of water;

Barrier – in hydrological terms a barrier tends to refer to a wider structure that can be raised in order to exclude tidal waters from the higher reaches of a river. The Thames Barrier is a good example of this sort of structure;

Barrage – tends to refer to a structure which is larger again, often spanning wide river mouths or estuaries, generally for the purposes of flood alleviation or power generation;

Today, I attended a further briefing, by the Environment Agency, which made it clear that what is proposed for the Parrett is a barrier, probably somewhere to the south of Dunball so as not to interfere with the passage of cargo to and from the wharf there. The barrier could be raised before very high tides in order to exclude the tide from stretches of river upstream of the barrier. This would help to prevent tidal surges lifting the level of the river a long way inland, would enable more floodwater to be pumped into the Parrett and would help to minimise the quantity of marine silt carried up the river. The anticipated 10 year timescale for this is too long and needs to be significantly shortened.

A barrage of the type proposed by a number of observers, including Roger Falconer, Professor of Water Management at Cardiff University is not currently planned. This envisages a lengthy ‘dam’ constructed offshore in order to create a ‘lagoon’ from which the sea can be excluded at high tide. This effectively increases the gradient of the river, giving it space to discharge the flow at all states of the tide. The advantages of the latter over the former are manifold. While a barrier will stop the incoming tide from raising the level of the River Parrett, it has the concomitant effect of preventing the discharge of water from the river too. A barrage enables the river to flow continuously. There is a huge difference in cost, with a sluice likely to cost millions and a barrage billions. The possibility of generating electricity from such structures can assist with the cost.

Today’s briefing also confirmed a programme of dredging an 8km stretch around the confluence of the Parrett and Tone rivers (3.5km on the Tone and 4.5km on the Parrett). This would return these lengths to the profile delivered in the 1960s Tone Valley Scheme (TVS). These parts of the system are judged by hydrological modelling undertaken following the 2012 floods to offer the most benefit in reducing the extent and duration of flooding. A contractor has already been appointed and the work will get underway as soon as ground and river conditions allow. The dredged silt is likely to comprise around 200,000m3 of material. It is expected that around 25% of the dredgings will be deposited directly on the banks, with the balance spread to nearby agricultural land. Many landowners have volunteered to take the material. Treasury rules previously made it impossible for the Environment Agency to spend the amount required to undertake this dredge but the Treasury appears to have waived the normal rules in this case and Defra will be providing the funds directly.

I think it is important at this point to scotch the nonsense peddled by some with their own agendas, that dredging of the river system on the Levels stopped because “the EU reclassified dredgings as toxic waste and the cost of its disposal was too great to bear.” All my enquiries indicate that this has never been the case. Sure, dredgings can be classified as contaminated, if they contain contamination above certain thresholds. While silt sampling will be undertaken before the dredging starts, it is not expected that any contamination will be found. It is also important to note that the dredging will only alter the lateral profile of the river channels, not the base as there is little difference depth-wise between the current base profile and that implemented as part of the TVS.

Many have called for the creation of a Somerset Rivers Board and this appears in the 20 Year Plan. Crucially, it is expected that this would take the form of an authority, with the power to act, not an advisory board. It will be important to clarify the proposed funding source for the Board. While Government has indicated a willingness to fund some of the capital work required to minimise the risk of a repeat of the 2014 flood, it has equally made clear that it expects revenue funding for ongoing maintenance dredging and other work to be found locally. There is talk of the Board raising funding via a local precept. I’m sure the details of how this is organised will cause much debate before agreement is reached.

The Plan says that “We must support farmers to maximise the benefits from catchment sensitive farming , especially regarding run-off.” Much has been written recently about the positive impacts that can derive from such action. Pontbren in Wales appears to be an excellent example of how this can be implemented, although the topography is not the same as that found on the Levels. In this example, we learn that water is absorbed into soil under trees 67 times faster that water is absorbed into soil under grass, giving the strong steer that we need to reforest parts of the upper catchments of our rivers. The growing of maize on steep slopes is a major cause of siltation as plants are widely-spaced with much of the ground bare and susceptible to erosion from heavy rainfall. Existing encouragement for farmers to conserve the condition of their soils appears to be wholly inadequate.

The Plan also calls for urban run-off to be managed through Sustainable Drainage Systems (SuDS). When the SuDS system is finally implemented, Somerset County Council will be a SuDS Approving Body (SAB), analysing and authorising the drainage proposals of new developments. The system has been horribly delayed and is now years late owing, in my view, to the objections of housebuilders, although they, perhaps predictably, blame Councils. The latest start date of April has just been pushed back to October. We heard during yesterday’s briefing that the principles of SuDS have already been implemented through the planning system, neutralising the flood impacts of new developments. I have my doubts and have not seen much evidence that this is regularly applied.

There is nothing in the Plan about the idea of helping those who have been flooded to leave the area. Clearly, individual property prices will inevitably have been severely impacted in some of the flooded areas. While some (perhaps most?) residents have expressed their desire to stay in areas and buildings that their families have occupied for generations and fight for improved flood resilience, it is clear that some do not wish to return. My view is that some form of assistance package to help people in this position ought to be provided. In France, some homes subject to unacceptable flood risk have been ‘blacklisted’, purchased compulsorily and demolished. I would not advocate such an approach here but I feel that the option of some form of assistance to such householders ought to be available. Interestingly, the Environment Agency said in today’s briefing that they did not believe that any properties on the Levels were irretrievably lost, i.e. likely to be subject to ongoing , repeated flooding. Sure, even with the full implementation of the 20 Year Plan, itself still not certain, some areas will flood but not to the point where properties are likely to be threatened annually. Perhaps on this basis, the idea of ‘aided departure’ is premature but I do feel sorry for those stuck with properties that they cannot sell at their former value.

I think it’s important to emphasise that even with the full implementation of the Plan, the moors would still flood in the event of a weather event of the magnitude of that experienced this winter. With climate change expected to make such weather more likely, we will need to keep the Plan under constant review to ensure its adequacy in the future.

So, overall, a good start. The challenge will be for elected representatives like me to keep the pressure on for money to be made available to implement the Plan. National Government moves quickly from one issue to the next and, while the Somerset floods caused the government sufficient discomfort that they (eventually) pulled out all the stops to get on top of the problem they may feel that they have already done enough to mollify an angry public. Our job will be to make sure that the funding to implement the Plan continues to flow long after the TV crews have packed up and gone home.

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