Would better maintenance ease Morpeth flood risk?

I recently spent three years on a major development in the south working in partnership with the Environment Agency on a Sustainable Drainage (SuDS) project, the basic principle of which is to keep the water where we can all see it, i.e. on the surface, manage it properly and design the swales (shallow sided ditches), ponds and lakes such that flood water is directed away from property and to its eventual river outfall, using areas of Public Open Space if necessary.

SuDS schemes have come to the fore simply because underground piped systems are never big enough and you can't easily see when they are blocked with an obstruction or silted up, hence the single biggest issue for any drainage scheme, either underground or overground, is basic routine maintenance.

This is an issue I have ranted on about for many years, to whoever would listen to the 'boring old engineer', so time to get the soapbox out yet again as, in my view, this important principle applies to the complete hierarchy of drainage from the uplands to the sea.

My experience in the 1980's working for a County Council in the Midlands on Highway Construction and Maintenance projects made me realise how important basic maintenance is to the upkeep of our highways and drainage infrastructure; that era was also the start of the decline in maintenance budgets with more work being put out to competitive tender to help a reduced budget stretch a bit further.

In those days we had works gangs that regularly went round cleaning out roadside ditches, cleaning 'grips' to take the water quickly from the roads and often working with farmers when there was any doubt over who owned ditches, hedges, verges, etc. Also at that time, cleaning out road gullies was high on the list of priorities, getting the silt out before it goes further down the chain to block up the system. All of the material generated from those jobs was stored in compounds around the County, allowed to 'compost' when it had high proportions of vegetation, then re-used as topsoil on the major road schemes.

We also worked closely with the Regional Water Authority, then in the late 80's, the National Rivers Authority (NRA), because during that time it was a common sight (certainly in the Midlands) to see long-reach excavators or draglines trundling along the banks of the rivers cleaning out the silt, gravel, trees, etc, that had been deposited.

I remember from Geography at School and my Geology course at University, learning how much rivers change due to the amount of material deposited in them from the adjoining land and how that material then moves downstream, often changing the course of the river throughout its many twists and turns.

So let's start with a series of questions, from the top to the bottom of the drainage hierarchy:

• When did you last see a farmer installing new land drains on his fields? (probably not actually worth doing, due to the next point).

• When did you last see a farmer or a Highway Authority cleaning out a field ditch or a roadside ditch, along with the 'grips' to get the water from the road into the ditches? (I drive 30,000 miles a year and can't recall the last time I was stopped at a roadworks job and witnessed any of this work going on).

• When did you last see a 'Gully Emptier' in your street, cleaning out the road gullies? (Many that I walk by, whilst out with the dog, look as though the lids wouldn't come off even if they tried and many are silted up).

• When did you last see manholes being cleaned out and pipelines being 'jetted'? (As a developer, we often get made responsible for upgrading existing drainage systems before new housing is added, and rightly so, however we then get the chance to view videos from cameras inside pipelines (honestly) and they are more often than not at least half full of silt due to lack of maintenance).

• When did you last see a stream, pond or a lake being cleaned out to improve drainage flows in and out of them? (This is a major problem for new SuDS schemes, as ponds and lakes can become classified as SSSI's, which then prevent them being cleaned out, due to the potential effect on wildlife — it only needs one Great Crested Newt).

• When did you last see a major river being cleaned out, removing the silts and gravel that build up? (In some rural areas, at times of low rainfall, you can often walk across rivers, just look at the Tyne around Hexham, the Till up at Wooler, etc).

• How often do you see fallen trees remain in the rivers for months on end?

• Look at the mouth of the river Wansbeck where it outfalls to the sea, between Cambois and the Sandy Bay Caravan Park, coastal erosion and the moving sands have virtually closed off the mouth of the river (worth looking on Google Earth, also, I'm not sure of the benefit of the weir near the A189, does this not prevent any 'self-scouring' that might have taken place, allowing more build up of material upstream?).

You only have to walk the banks of the River Wansbeck from Mitford Road to the East Mill weir and see the amount of gravel that has built up, particularly around the main road bridge and near to the stepping stones.

If a 2km length of river through Morpeth was cleaned out say, 10m wide x 1m deep, my calculator says that is 20,000 cubic metres in volume, or 20,000,000 litres of water (yes, that's 20 million litres) that would have stayed in the river and not entered the main street or the many houses and shops that were devastated, at least some people may have escaped the chaos.

I'm sure the upstream dam and temporary storage that will be created by the EA will be welcomed by the people of Morpeth, but that is five years away and the planning application will no doubt raise an objection from some 'eco-warrior' to protect a rare orchid or wildlife habitat, potentially stringing it out even further.

Something needs to be done now and, as Robert Pollard pointed out in your letters pages recently, many instances of flooding are directly related to my earlier points regarding highway drainage, ditches, gullies, manholes, etc, now there is a challenge for the new Unitary Authority with all of their budget cuts?

What the people of Morpeth do not need is the sort of response last weekend from the EA to the Residents of East Mill, who have reported 'a new island having been formed by gravel in the middle of the river'.
An EA spokesman is reported to have confirmed: "We are carrying out a survey to assess the impact of gravel on flood risk in Morpeth, and have to prepare a gravel management plan".

For goodness sake, here's a 'gravel management plan' for you — take it out of the river and use it elsewhere to prevent coastal erosion or sell it to the construction industry. For every 10m3 skip full of gravel you remove from the river, you create a hole for 10,000 litres of water to stay where it was intended, it's hardly rocket science.

So, rather than continuing to build the river defences higher (where do you stop?), as the EA seem likely to recommend, just lower the river.

GEOFF WOODCOCK
Widdrington Station
Morpeth