chapter  6
22 Pages

Upland hydrology

ByJOSEPH HOLDEN

The uplands of the oceanic temperate-humid zone, on which this book is focused, are dominated either by thin soils on steep slopes or, where slopes are more gentle, by thicker organic soils which range from raw peats and earthy peats to organo-mineral soils. Where slopes are gentle and soils in the uplands are deep, they tend to be dominated by organic matter (e.g. Paramo ecosystem of the Andes; Buytaert et al., 2006). Organic soils of the uplands tend to have a large water content and are quickly saturated during rainfall thereby generating fast-moving surface or near-surface hillslope runoff. This is characteristic both for gentle upland slopes with deep organic soils and steeper slopes with thin soil layers, and creates a system allowing water to be rapidly shed from headwater catchments. This means that, even without management intervention or future climate change, such systems remain source areas for flooding. The impact of management practice on flood risk depends on a number of factors including drainage network structure, local topography and location of a given management practice with respect to these landscape features.