Soil roughness and overland flow

Soil surface roughness affects surface depression storage, water infiltrati on, overland flow velocity as well as overland flow organisation. This pape r attempts to give an overview of our knowledge of the effects of roughness on surface runoff and to indicate areas where further research is most nee ded. The relationship between soil surface roughness and depression storage is relatively well understood. On the other hand, few studies exist on the relationship between roughness and the infiltration characteristics of a t illed surface, although this may be more important. Insights, which have be en developed over the past few years, may in the near future lead to a bett er prediction of the hydraulic resistance of interrill and concentrated ove rland flow. Recent studies have also provided important information on the effects of roughness on runoff patterns.