Advances in Water Treatment and Enviromental Management

222 WATER TREATMENTThe response of the natural world to such activities may be immediate. In 1984 oneof a dozen such ponds was created beside the Warwickshire Learn as part of aland-drainage scheme. Before the machine had actually finished, a not-so-shymoorhen was building its nest on the island which the driver had created for it asa relatively safe refuge from such nocturnal marauders as hedgehogs, which snuffleout moorhen eggs as a special delicacy. On a river near Evesham, the machines, aspart of a flood alleviation scheme, extended a large bay and made a pool within theriver bed. No sooner was the new pool created than the first swallows were dippingand swooping over it; and, best of all, by late afternoon of the first day, the bank topwas crowded with bicycles thrown down in the grass by the village children whilethey enjoyed their new bathing-pool.This kind of work has proved more interesting for the machine drivers who previouslytook a pride in the neatness of their straight channels, but who are now rising tothe challenge of doing an ‘untidy’ job. Farmers, whose co-operation is essential indonating riverside land for tree planting, ponds and other habitat creation, havebeen universally generous, both on intensive arable land in the east and in the hillcountry in the west.River engineers who take greater care and thought about the environment oftenfind there are practical benefits which help the actual efficiency of the scheme.Ponds can sometimes be created in order to provide the material for raised floodbanks, thereby saving the cost of importing spoil. Raised banks themselves can bespread with minimal top soil (another saving), and sown with low-growing grasses.This can reduce massive mowing costs, such as that currently incurred by theNational Rivers Authority Severn Trent Region on 200 miles of flood bank alongsidethe River Trent. The environmental bonus will be many more wild flowers andbutterflies.Riverside trees will shade out aquatic weed and are among the best bank stabilisers.On the River Clwyd in North Wales, a river engineer came up with a particularlyneat solution to a problem of bank erosion in 1977. A willow had fallen into thestream, and as a result, the river, nudged out of its regime, was eroding the adjacentbank. The engineer removed the offending tree, and chopped it into logs with whichhe filled mesh baskets, which he then set into the newly eroding bank. These grewimmediately, efficiently holding the bank against erosion. Returning 10 years later,the engineer was able to admire a riverside grove of 20ft willows still attractivelysolving the problem which their parent tree had created.CONCLUSIONDrainage schemes have been massively boosted by public money. For this reason itseems only fair that such schemes respect and even enhance the common heritageof the landscape, and since 1981 this has indeed become a legal responsibility ofdrainage engineers. Currently, the National Rivers Authority Severn Trent Regionspends a mere 5% of its total annual river maintenance budget on just suchendeavours.If everyone responsible for the maintenance of watercourses rises to such aproportionally modest commitment, then the loveliest of our existing rivers will notbe lost, and all the miles of denuded drain which lie waiting, like sleeping beautiesin intensive care, will, over the space of a generation, recover life and elegance asthey carry away their essential cargo of flood-water to the open sea.