Effects of peatland drainage management on peak flows

摘要

Open ditch drainage has historically been a common land management practicein upland blanket peats, particularly in the UK. However, peatland drainageis now generally considered to have adverse effects on the uplandenvironment, including increased peak flows. As a result, drain blocking hasbecome a common management strategy in the UK over recent years, althoughthere is only anecdotal evidence to suggest that this might decrease peakflows. The change in the hydrological regime associated with the drainage ofblanket peat and the subsequent blocking of drains is poorly understood,therefore a new physics-based model has been developed that allows theexploration of the associated hydrological processes. A series ofsimulations is used to explore the response of intact, drained andblocked drain sites at field scales. While drainage is generally found toincrease peak flows, the effect of drain blocking appears to be dependent onlocal conditions, sometimes decreasing and sometimes increasing peak flows.Based on insights from these simulations we identify steep smooth drains as thosethat would experience the greatest reduction in field-scale peak flows if blocked andrecommend that future targeted field studies should be focused on examining surface runoff characteristics.