The current issue of “The Furrow”, the John Deere journal of April 16, prompted me to think again of my own work on top soil reservoirs and what is beginning to be called bio-engineering in flood control. Sands will hold about their own weight of water, clay two times, and peat 16 times. Composts made from urban wastes, including a wide range of industrial wastes, will hold 5 to 15 times their own weight. Put that into context of the Dutchman, Cornelius Vermuyden, who, in the 1650’s drained the flats of East Anglia. He knew that there had to be not only big, straight dykes but also sacrifice flood zones which were adequately boundaried and with enough capacity to take the worst water emission flow rates from the higher land. Now increase the organic matter levels of all the soils in the catchment area. Finally, plant grass, herbs, shrubs and preferably trees and do so at all levels right up to the highest. The cohesive effect of roots and the evaporation by active plants will buy time to even out the flow to what the lower water courses, adequately dredged, can cope with. As global warming increases extremes, we need to match that, preferably before the event, with buffers that even out flow rates.
Bill Butterworth 13 April 2016
Also see, “How to make on-farm composting work”, by Bill Butterworth, published by MX Publishng, London.