Analysis of River Meander Development and Relationship between Vegetation and Bank Stability: River Lostock, Preston, Lancashire.

Abstract

River channel morphology is constantly changing. The course of a river adapts and
forms meanders, this is because there are several factors that act upon a river and cause
it to erode. This paper studies the vegetation type and density that exists on a bank, flow
pattern of the river, and bank composition and how this affects bank stability.
This paper will investigate the causes and effects of erosion on six meanders of the
River Lostock, Preston, Lancashire, England. A vegetation survey was carried out; the
total vegetation cover was recorded along with the types (shrubs, trees, and grass) at the
mid and top bank of each meander. To gain the flow pattern data, velocity was recorded
at inner, middle, and outer sections of the meanders. Bank composition was recorded
using a texture by feel method. The percentage of erosion at each bank was recorded.
The results of this study found, the level of erosion on river banks depend on the
amount of total vegetation cover on the bank. However it was inconclusive as to which
type of vegetation is best for stabilizing the banks. The flow pattern showed that
velocity is greatest at the outer bend and least great at the inner bend. Also found is that
vegetation influences velocity, the more vegetation there is on a bank the less great the
velocity will be. The results of the effect of bank composition on erosion were also
inconclusive.