Scaling up and out in runoff process understanding: insights from nested experimental catchment studies

Abstract

Received 30 March 2006 Accepted 25 April 2006 Background International research initiatives such as Hydrology, Environment, Life and Policy (HELP) and Prediction in Ungauged Basins (PUB) have underlined the need for hydrologists to upscale process understanding gleaned in small experimental catchment studies to aid management decisions at larger spatial scales (Sivapalan et al., 2003; Bonell et al., 2006). Arguments as to why this has proved difficult are well rehearsed, and calls for experimentalists to work more closely with modellers to aid this task are widespread (e.g. McDonnell, 2003). One constraint on hydrologists meeting such challenges is that the research infrastructure required to reveal hydrological functioning at nested and larger spatial scales is lacking. Another is the risk in losing information moving from detailed process-based work to more generalized approaches at larger scales (Sidle, 2006). Here, we share experiences and insights from an upscaling initiative in the Feshie catchment in the Cairngorm Mountains of Scotland; this combines consideration of the dangers inherent in extrapolating from small-scale experimental catchments with discussion of the benefits offered through integrated use of environmental tracers and a geographical information system (GIS) to gain insight into the hydrological behaviour of larger catchments. The potential in using readily available spatial data (in conjunction with the insights from targeted field investigations) in deriving regionally based predictions of catchment function is also examined.