Long-term change of the River Liza, Wild Ennerdale, England

摘要

The long-term change of the River Liza in the Ennerdale valley, Cumbria, was mapped and analysed using Geographical Information System (GIS) techniques. In this paper, the focus was on the use of GIS to investigate, map and analyse the changes in the River Liza's meandering channel system. Cartographical modelling, planform morphological analysis and cross-sectional analysis were methods of analysis employed in the study. The datasets used were largely digitized River Liza's channel from the historical maps, aerial photo maps and Differential Global Positioning System (DGPS) Field Survey data. It was discovered in the study that River Liza maintained a stable pattern of movement until it became diverted at Latitude 54° 30' 47.07" and Longitude 3° 18' 15.05" between 1993 and 2009. However, the channel's widths and depths have been far from stable; they have been increasing as a result of constant erosion of the bank and deposition within the channel, especially since the 1970s when there have been increases in rainfall in the UK. Apart from the presence of man-made features like bridges and bulwarks, the River Liza is discovered to be one of the important features in Ennerdale Valley where natural processes have been allowed to take their course in shaping the landscape and the ecology of the valley.