b'Session IV: Long-term in-situ monitoring and modelling ofwater qualityCan the sediment pollution gap from intensive livestock farming be closed? Assessment using the North Wyke Farm Platform, UKCollins AL1, Zhang Y1, Upadhayay HR11Sustainable Agriculture Sciences, Rothamsted Research, North Wyke, Okehampton, UKWhilst much research in the UK on the impact of modern intensive farming on soil erosion and resulting externalities to water, including excess sediment loss, originally focussed on arable systems, there has, for some time, been a growing recognition of corresponding issuesassociated with intensive livestock farming. Ongoing research on the North Wyke Farm Platform in southwest England is monitoring sediment loss using 15 micro-catchments hydrologically -isolated by a network of French drains and instrumented in situ with equipment for discharge and turbidity measurements. The core monitoring work is providing a basis for estimatingmodern day sediment loss. In turn, these estimates are being compared with corresponding estimates of modern (pre-dating the post-World War II intensification of farming) back sediment delivery to rivers constructed using palaeolimnological evidence. The final part of the work is investigating the scope for closing the sediment pollution gap, characterised by exceedance of modern back ground sediment delivery to rivers, on the basis of increased uptake of bestmanagement practices applicable to lowland beef and sheep farming systems.18'