Kamilla Skaalsveen

Forsker

(+47) 406 49 996
kamilla.skaalsveen@nibio.no

Sted
Ås - Bygg F20

Besøksadresse
Fredrik A. Dahls vei 20, 1430 Ås

Sammendrag

The hydrological processes associated with vegetation and their effect on slope stability are complex and so difficult to quantify, especially because of their transient effects (e.g. changes throughout the vegetation life cycle). Additionally, there is very limited amount of field based research focusing on investigation of coupled hydrological and mechanical influence of vegetation on stream bank behavior, accounting for both seasonal time scale and different vegetation types, and none dedicated to marine clay soils (typically soil type for Norway). In order to fill this gap we established hydrological and mechanical monitoring of selected test plots within a stream bank, covered with different types of vegetation, typical for Norwegian agricultural areas (grass, shrubs and trees). The soil moisture, groundwater level and stream water level were continuously monitored. Additionally, soil porosity and shear strength were measured regularly. Observed hydrological trends and differences between three plots (grass, tree and shrub) were analysed and formed the input base for stream bank stability modeling. We did not find particular differences between the grass and shrub plot but we did observe a significantly lower soil moisture content, lower soil porosity and higher shear strength within the tree plot. All three plots were stable during the monitoring period, however modeling scenarios made it possible to analyse potential differences in stream bank stability under different vegetation cover depending on root reinforcement and slope angle.

Sammendrag

Bakgrunnen for fiskeundersøkelsen var å avdekke eventuelle skader på ørretbestanden i forbindelse med byggingen av ny E-18 Sky-Langangen. To strekninger ble el-fisket. Det ble funnet god tetthet av 0+, noe som viser et godt resultat av gyting og klekking for sesongen 2009/10 på tross av økte tilførsler av jordpartikler fra anleggsarbeid. I 2005 ble det fanget flere 1+, men for undersøkelsene gjennomført i 2007 og 2008 på den ene strekningen (stasjon 2) var det dominans av 0+ som for undersøkelsene i 2010. Beregnet tetthet av fisk var på samme nivå som for tidligere fiskeundersøkelser.