Holding back the flood: tackling the SWMP monster

Four years ago, the Pitt Review made 92 recommendations to reduce flood risk. Richard Allitt of consultancy RAA says funding is just one limit to progress.

Surface Water Management Plans (SWMPs) are the vehicle for understanding the potential flooding mechanisms within a given study area and for assessing the risk – the combination of the likelihood and the consequences – of flooding. Ideally a SWMP will identify the flooding risk from all sources including pluvial (surface runoff), fluvial (rivers), sewers and groundwater as in the majority of instances the actual flooding mechanisms is from a combination of all these sources.

It may be perceived that these would have an overlap with other flood risk information, but in fact any previously available assessments can be incorporated into the SWMP without having to duplicate work; this then results in all the information being in one place.

Pitt review
Following the serious floods of 2007 Sir Michael Pitt was asked by the Government to review the arrangements in England & Wales for assessing the risk of flooding, the institutional arrangements and responsibilities, the preparedness of the various public bodies and the general public. Pitt made 92 recommendations in his two reports and the vast majority of these were accepted by the Government.

A particularly important aspect of these recommendations was to give the Upper Tier Local Authorities more responsibilities and to designate them as Lead Local Flood Authorities, with the role of taking control of flooding matters within their district under the overall guidance of the Environment Agency. Now, for the first time an Authority became responsible for groundwater flooding whereas before there was none.

The main thrust of the local management of flooding risks was recommended to be the use of SWMPs which were to be cyclic in nature and repeated or updated every five years. The recent very wet weather during June 2012, the widespread and severe flooding and the unfortunate fatality has reinforced just how vulnerable we are to the variations in climate in the UK. Professionals working in the water sector have always been aware of the link between the variations in rainfall and flooding; it is only now that the media and the general public are beginning to appreciate this linkage.

With severe flooding since 2007 in Gloucestershire, Hull, Carlisle, Sussex, Hampshire, Wales, Northern Ireland, Shropshire, West Midlands, Yorkshire, Lancashire, Cornwall, Devon there are now few places that have not experienced serious flooding in recent years. Local politicians now ignore the risk of flooding at their peril.

Since 2007 there have been tremendous technical advances in our ability to assess the risk of flooding. In 2007 we generally had two types of hydraulic modelling programs; those for modelling rivers and those for modelling sewers. There was a misconception at that time that because the river modelling programs were good at simulating the flooding of open fields they would also be good at simulating the flooding in the streets in urban areas; however that was soon proved not to be the case because of the substantial differences in hydrology and the need to work at finer detail.

There are still some authorities, advisors and consultants who are trying to ‘force fit’, using river modelling programs in urban areas, but thankfully the number of these are in decline.

In 2010 there was a step change in the availability of hydraulic modelling programs capable of providing sufficient ability to model all of the potential flooding mechanisms including sewers, rivers, pluvial runoff, groundwater and if necessary breaches in dams or flood defences; all seamlessly within a single program.

There are currently only a very small number of programs capable of doing this and there are also only a very small number of skilled modellers capable of using these more advanced programs. The number of skilled modellers available is increasing but perhaps not at the rate we require.

One of the main aspects of the Pitt Review recommendations was the institutional changes required in the Environment Agency and especially with the upper tier local authorities. Most local authorities have managed to get some staff involved in flooding, but in many cases this is only a single person or a very small team with little or no expertise or experience in flooding or drainage.

Many of these people have been involved in highway matters and are having to quickly learn a whole new discipline. Without exception we have found a great deal of enthusiasm within local authorities, but very little funding and very large gaps in capacity and capability. The biggest challenge being faced in England and Wales to the implementation of SWMPs as a means of understanding and reducing flooding risk is the absence of appropriate levels of funding both to implement studies and also to develop and build up the required skill bases within Local Authorities.

The forthcoming role of upper tier local authorities to adopt Sustainable Drainage Systems (SuDS) will stretch the meagre resources even further.

There are some local authorities who stand out as ‘Exemplars’ and have embraced the concept of SWMPs and have used them very effectively to understand flooding risks, justify flood alleviation schemes, substantiate applications for grant aid and to actually progress to constructing these schemes.

The recommendations from the Pitt Review included placing an obligation on all stakeholders (councils, Environment Agency, Highways Agency, Network Rail, Internal Drainage Boards, water and sewerage companies et cetera) to share information. From our experiences there are some variations around the country but generally there has been a high degree of cooperation and sharing of data. The ideal situation would be when all the stakeholders agree that a joint scheme would be to everyone’s advantage and they agree to jointly fund the scheme.

However in practise the different areas of responsibility, the differing design standards, the substantially different business planning timescales and differing priorities for scare funding all work against co-funding of schemes.

From our experiences these differences have not prevented people from trying, but so far with only limited success. Are we progressing fast enough? The simple answer to this is ‘No’.

The severe flooding of 2012 has shown to the general public that very little has changed since 2007. At a recent seminar at the Institution of Civil Engineers the same question was asked with a general consensus that we are moving in the right direction but at a frustratingly slow pace.

There is no doubt that with more and consistent funding we can progress a lot faster, but it will remain for the politicians to decide what pace we should progress at.

There are a small number of consultancies with highly skilled modelling staff who are constantly being undermined by less experienced and less skilled companies claiming that they can undertake SWMPs with antiquated river modelling software with local authorities becoming progressively more disillusioned with the results.

If we are to progress with effective surface water management planning, we as a country, must stop awarding studies solely on price and recognising the need for highly skilled and competent staff.

Overall, looking at the progress we have made over the past five years, one can be heartened and remain hopeful that the next five years will see even better progress.

Action inspires action. Stay ahead of the curve with sustainability and energy newsletters from edie