Unit 1 - Essays - River Floods, Channel Flows and Storm Hydrographs

Question 1

With the aid of examples, assess the extent to which land use changes affect water flows above ground and below ground.

Answer 1

Point: Urbanisation drastically changes surface water flows by creating impermeable surfaces.
Point: Changes in forest cover due to deforestation disrupt interception, altering both surface and subsurface flows.
Point: Agriculture can both increase and decrease water movement above and below ground, depending on methods.
Point: Human drainage systems and river modifications significantly adjust natural water flows above and below ground.

Question 2

‘Rock type is the most significant influence on the shape of a storm hydrograph.’ With the aid of examples, how far do you agree?

Answer 2

Point: Rock type is a crucial influence on hydrograph shape because permeability controls infiltration and runoff rates.
Point: Relief (slope steepness) and basin shape can be even more influential than rock type.
Point: Vegetation and human land use significantly affect hydrograph shapes, often compounding or mitigating the role of rock type.
Point: Climatic factors like rainfall intensity and duration sometimes overshadow rock type in determining hydrograph shape.

Question 3

With the aid of examples, assess the relative importance of the factors that caused a recent river flood event.

Answer 3

Point: Rainfall intensity and duration were critical causes, but their relative importance differed between Bangladesh and Boscastle.
Point: The geology and basin characteristics significantly shaped the floods’ severity, showing notable spatial variation.
Point: Human-induced land use changes were pivotal, especially urbanisation blocking natural drainage.
Point: Deforestation and land use changes contributed differently, depending on scale and prior conditions.

Question 4

‘River flooding impacts people more than it impacts the environment.’ With the aid of examples, how far do you agree?

Answer 4

Point: Flooding often leads to immense human suffering, disrupting lives more significantly than ecosystems.
Point: Environmental impacts, though severe, often allow natural recovery and even regeneration.
Point: Across both localized and national scales, human systems are more vulnerable and slower to recover than the environment.
Point: In some cases, flooding causes major environmental degradation, with slow recovery.