Discus to the extent to which you believe Carlisle floods 2005 were the result of intense rainfall rather than the physical characteristics of the drainage basin

Many geologists and people could say that the floods were cause by human impact, but in reality, that would be unlikely, but not impossible. It would not have been one of the major factors that cause the floods in Carlisle. However for example if, the vegetation in the river or around the river basin was removed or cut down, for the use of more land, or materialistic things, this could have affected the velocity of the river, as vegetation such as trees, act as an interception in the river causing its velocity to slow down. Also the land around the river basin is grassland and arable farming, especially in the valleys, so these are used to the farmer’s advantages, and they farm on these particular lands, mean that the vegetation may be harvested, or grazed on.

Another factor that could have affected the floorings, were the physical features of the drainage basin. As the River Eden is situated in the midst of valley’s, in the highlands in the north of England, there were many areas with steep slopes, which characterised the drainage basin, but there were lower gradients around Carlisle, meaning that the River Eden could have already been prone to its banks bursting, without the heavy rainfall. There was also alot of impermeable rocks on the highland, and near the Vale of Eden there was sandstone, with a fair amount of limestone, meaning that the water would of not been able to infiltrate or percolate through, which would lead to surface runoff and overland flow. Even if some of the water was able to be absorbed a little, after a short period of time, the rocks would become fully saturated, still leading to rapid overland flow or surface runoff.

During the second part of the first week of 2005, a very mild moist air engulfed the UK, causing gail force south-westerly winds. A depression centre passed near to the north of the area on Thursday 6th January, with cold fronts bringing strong frontal uplift and convection. The rainfall increased over the high ground of Cumbria as the airstream was forced upwards (the orographic effect) the main evidence though that points to the flooding, is the rainfall. The rain led to the overflow of the river, which caused surface runoff. We know this from the hydrological graph which showed the peak rainfall being 50mm, and the peak discharge being 55 mm. The graph also shows how the rainfall from the previous days affected the capacity of the soil, making saturated, meaning not a lot of water could have been percolated through the soil. There is a steep gradient in the rising limb, to show how quickly the rain was walling, and a steep falling limb, showing the rate of velocity of the water droplets flow, which is also descending very steeply.

Although we can deduce from the evidence that the rainfall was the main cause the human and physical factors, also had parts in the major flooding of Carlisle in 2005, and it could not all be blamed on the rainfall.