In the summer and autumn of 1973, 25 rain troughs were operating below canopy and four in clearings of a predominantly coniferous forest in the Velen hydrological research area. The collected rain water amounts were measured 14 times (about once a week). Using these data and the records from a tipping-bucket rain gauge in a simple model for throughfall, it was found that the overall water storage capacity of the forest canopy was about 2 mm and that the free throughfall coefficient p was about 0.5. Results from 50 photographs taken upward from the troughs indicate a smaller p-value. The time for evaporation of the intercepted water after an average rain storm is roughly estimated as 5 h. About 26 % of the total rainfall was intercepted and evaporated.
- Received March 21, 1974.
- © IWA Publishing 1974