30 Jahre Wassermessstation im Emmental

Birmensdorf

1959

S. 179-224

8 Abb., 16 Tab., 6 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200157630

The founders of the water measuring stations in the Emme Valley had the following objectives: 1. To quantitatively support the long known beneficial influence of afforestation upon the water regime of torrents. 2. To investigate as far as possible the causes of the different behavior in forested and non-forested watershed areas. Engler (1) and Burger (2-4) at the time directors of the forest experiment station, hve presented the results of their investigations in four publications. The existing work is a summary of the results of the last 30 years, since the alterations of the measuring shall, on the basis of the results obtained, be repeated here in condesed form. The Sperbel drainage was almost completely forested, partially with a beautiful mixed forest. It was under the conditions of climate and geology of the Emme Valley. It used approximately 10% more water expressed on the basis of the same rainfall than did the Rappen drainage which was afforested only along the stream channel with Norway Spruce but was otherwise grazed. Investigations concerning interception of forest and forest litter and grass vegetation were not carried out in the area under investigation. Yet we would surely consider the experience from other areas to be correct when we estblish the fact that in the forest less precipitation reaches the soil thn in the open areas. O the other hand, evaporation is less from under the protection of forests than the open. The transpiration of the woody growth must accordingly exceed the water consumption of the less deeply rooted grass vegetation. A comparison of the summer and fall tabulated values offers a clue to this fact.One obtains an interesting insight into the factors controlling the water regime by comparing the individual year balances with the 30-year mean value. Besides th quantity of precipitation, the seasonal distribution above all else controls the percent of runoff. The role of the current water reserve in the soil is also great. The most important point concerning this is brought together at the end of section C 2.