The potential role of freshwater luminescence measurements in exploring runoff pathways in upland catchments

The forested Coalburn catchment 1.5 km(2) in northern England experiences e pisodic stream acidification. Tn plan for sustainable management Of the pla ntation forest cycle, an understanding is required of the flow pathways and hydrochemical routing signatures of the organic and mineral soils that mak e up the source areas for runoff. A tentative mixing model, based on simple water chemistry exists for the major (terrestrial) sources and buffers of acidification; it is being expanded and consolidated by a detailed approach to the organic components of runoff, via sampling and analysis of the lumi nescence of surface waters at the catchment outlet and in two distinctive f eeder streams. Luminescence measurements are presented that permit a simple apportionment of source areas. However, the technique also appears to have potential for identifying differential flow sourcing between the acrotelm and catotelm of intact peat deposits and for clarifying tile influence of f orest root systems in altering the organic chemistry of infiltrating waters . Applications may include the monitoring and prediction of coloured water events for the water supply industry. Copyright (C) 2001 John Wiley & Sons, Ltd.