1. The relief of the upper course of the river basin in the Yorkshire dales is very steep. This promotes fast runoff from the slopes into the river and less soil infiltration.
2. There are seams Permian Limestone that allows water through its structure quickly. There is also a substantial amount of clays that are impermeable, this water cannot infiltrate the soil and hence gets into the river quicker - reducing lag time.
3. At high altitudes in the upper basin vegetation is heather and moor lands that has low interception rates. There are area of scattered coniferous trees with better interception year round, while deciduous trees offer good interception until they loose their leaves. Much of the lower basin is farmland offering little interception.
4. Peat soils in the upper basin act like a sponge and absorb much of the summer precipitation, lowering peak discharge. From late autumn these stores are full and hence subsequent water finds its way into the tributaries.
5. The Ouse section of the basin is flat and receives about as much precipitation (640mm per year) as is lost through evapo-transpiration (540mm per year). The water that floods York hence comes from the Dales area which receives heavy rainfall, which ends up in York via the Swale, Ure and Nidd tributaries.
Group 3
Lam Hoc Sing
Khoo Lian Keat
Wong Yi Xiong
Justin Yong Li Hong
Dinesh Manoharan
Not bad...
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