The Archive contains articles which are either of general interest, or have been the cause of concern in the past and remain unresolved.

Out of Sight is Out of Mind – Why Does Rickmansworth Flood.

Over the past few months we have become used to water lapping on to the pavements, and occasionally into shops and businesses, in High Street and Church Street. Although most of us can remember the effect of very heavy rain a few years ago, with serious flooding along much of the High Street and out towards Ebury roundabout, the constant low level flooding in the main streets of the town is new. So what is contributing to it, apart from autumn rainfall about 20% higher than the average?
Firstly, and probably most importantly, the public drainage system along and from High Street and Church Street is many years old and its capacity is unknown as, in some places, are its actual routes. Add to that the fact that the County Council is responsible for the gullies (the vertical bits down from the road drains) and the road drains whilst Thames Water is responsible for the public rainwater sewers. The road drains flow into the rainwater sewers and then, whilst some of the rainwater sewers flow into the Town Ditch, others flow downstream along the valley of the Colne. The Town Ditch is, after a change a couple of years ago, the responsibility of the Environment Agency. So a drop of rainwater falling in part of High Street could pass from the County Council’s domain to Thames Waters’ to that of the Environment Agency in the course of a couple of hundred yards travel. Not the easiest system to manage.
Secondly, the flow in the drains and sewers can be quite slow because, from the High Street to the river, the town is on flood plain and almost flat. That slow flow will accelerate the build up of deposits within the drains and sewers, particularly where there are awkward corners and changes of gradient, further slowing the flow in a vicious circle of reducing capacity.
Thirdly, there has been a massive increase in the number of buildings and amount of hard landscaping within the town centre since the drains and sewers were built over 80 years ago. What has been built over those 80 or 90 years? How about Northway and Penn Place, Three Rivers House and the car parks, Watersmeet, The Cloisters, most of Joan of Arc School as we know it now and much, much more. On higher ground some of the rainwater flowing off new buildings and hard landscaping would go into soakaways but it is difficult to have operating soakaways when the water table is about 2 feet below the surface. It will be interesting to see the impact of the massive developments of the past few years, and still underway, when a major rainstorm occurs and the run-off pours into the rainwater sewers and reduces their ability to take the water from the highway drains. So, little by little, the town has generated more and more rainfall run-off yet the core network of drains and sewers has remained largely unchanged and, in all probability, with its capacity reduced.
In towns undergoing major expansion a typical requirement is for road drains to be able to cope with a steady rainfall of 25 mm (1 inch) per hour whereas it is almost certain that 2 or 3 hours of rain like that in Rickmansworth would leave half the shops on the south side of the high street flooded, with ruined floors and any stock on lower shelves destroyed. But what is extraordinary is that, under current legislation, in towns like ours planning permission cannot be made subject to a substantial contribution to work to alleviate the increased risk of flooding. In other words, even a major developer cannot be forced to pay for work to prevent the increased risk of flooding that could be created by his development.
So what should be done? Perhaps we should start by refusing all planning permission for development in the town centre, or immediately beyond it, which could increase the flow of rainwater into the highway drains and rainwater sewers. Next, complete a survey of the drains and sewers so that we know both where they are and their condition. Then clean out the whole length of the critical drains, sewers and the Town Ditch. Finally, if the survey demonstrates that, even with the system at its cleanest, it cannot cope with heavy rainfall, maintain the moratorium on development until the town’s drainage system is upgraded to meet the modern day demand. Remember that the climate experts are forecasting wetter autumns and winters, so the flooding problem can only get worse if nothing is done. In the meantime, please keep the Association’s committee informed about changes to the pattern of flooding.

Water Everywhere

Samuel Pepys recorded in his diary in 1663 that it rained non-stop from June to December with severe flooding throughout southern England, so Autumn 2000 was not exceptional in that respect. The evidence for warm climate cycles is in the historic records: the last cycle started about 1880 and peaked about 1950. Two years ago the rivers around Rickmansworth and in Southern England ran dry, all the environmentalists wrung their collective hands, booked their slot on the TV and pronounced that we would be living in a desert in 10 to 20 years. Even TV gardeners led the way with their Mediterranean planting schemes and mulching to conserve water. Well, it seemed a good idea at the time. However my mulch was last seen in late Autumn 2000 floating down Berry Lane on a tidal wave of "drought". So much for the cactus garden, it’s back to the rainforest for me.
The drought, of course, had the hosepipe bans enforced, with the threat of neighbours squealing on – sorry reporting – those criminals who use a hosepipe in the summer. The charge for an outside tap went up along with the threat of water meters, the consumer to bear the cost of installation of course. Will there be a reduction this year, I wonder? Silly me, water charges only go up and rain comes down along with that other stuff from the sky.
Had a look recently at the Colne or Chess? Even the canal towpath opposite Tesco’s was flooded, as was the Aquadrome car park.
I don’t suppose the fact that the planet Earth on its eleven-year cycle around the sun was at its closest to the sun in 1998, the closest for a decade, had anything to do with the drought. No, of course not, it was all down to global warming we were told, whilst scientists popped their bids in for study grants and the European Governments raised green taxes.
Of course as the oceans warm up you get more evaporation, and hence more clouds, and heaven forbid, a natural action of more clouds more precipitation; sorry, rain to you and me. The fact that it takes two years for the ocean to release its vapour on us only goes to show that Nature does things in her own time, and according to the TV schedulers or spin-doctors from the Department of the Environment!
"Don't Panic, water is a bit short" we were told during the drought, "in the meantime and to be on the safe side we will have to raise the water rates for 'supply improvements'". Well, on the bright side, a new storm drain was proposed for Valley Road, or we could have a new lake in Rickmansworth.
I don't suppose that any of this year's excess rain was redirected back into the aquifer. No, too simple and the wrong type of rain; after all, the water was too polluted, we were told. Ah that's where my mulch went to! So perhaps we should purify it before restoring the excess to the aquifer.
I wonder if Thames Water has ever heard of reed bed purification, a cheap, clean and environmentally friendly way of cleaning large amounts of water? Once again I’ve got it wrong, water companies do not get paid for putting water back into the earth, only taking it out.
There is a nice plot of water meadow up for sale in Moor Lane, highly suitable for a reed bed and willow tree plantation with lots of nice insects and birds, "a real natural water filter", better than all the bottled stuff in the shops, with a borehole system to top up the aquifer for future years.
Too simple, too expensive; better to have cheap housing in places like Moor Lane and the old depot near Stockers Lock, both areas of flood plain. Got to house people somewhere after all’s said and done, and a flood plain would seem as good a place as anywhere to put them. We can all wring our hands every decade or so when a flood occurs. Apart from the personal misery that flooding creates, the costs are passed on with a general increase in local house insurance, not to mention increases in council tax.
We have had it all in the last few years; no water, too much water. Is it not time the Three Rivers DC did something, instead of just talking about it? Such as actually plant some trees and tell the water companies that there is no such thing as the wrong type of rain, only poor water management. Is it not time to put things right?
By the late Bob Warren, Committee Member

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