Option A: Freshwater: Practice Questions

What is the primary distinction between physical water scarcity and economic water scarcity?

Consider a storm hydrograph for two different drainage basins receiving the same amount of precipitation. Basin X has steep slopes and urban concrete surfaces, while Basin Y is flat and heavily forested. How would the hydrograph for Basin X typically compare to Basin Y?

The concept of virtual water trade suggests that water-stressed nations can conserve their domestic water resources by doing which of the following?

Which term describes the geographical area of land where all surface water converges to a single point at a lower elevation, such as a river mouth or a lake?

In the context of the Hjulström curve, what is the most likely reason why very fine-grained particles, such as clay, require a higher critical erosion velocity than larger sand particles?

Define economic water scarcity and provide one reason why it occurs even in areas with sufficient physical water resources.

The following data shows the hydrological response of a river following a storm event: Peak rainfall was recorded at \( 14:00 \) hours, and the resulting peak discharge was measured at \( 19:30 \) hours.
a) Use the formula \( \text{Lag Time} = T_{peak\_discharge} - T_{peak\_rainfall} \) to calculate the lag time for this event.
b) Explain how the replacement of natural vegetation with impermeable concrete surfaces would likely alter both the peak discharge and lag time shown on a storm hydrograph for this area.

Using a named example of an international drainage basin, evaluate the socio-economic and environmental trade-offs associated with multi-purpose river schemes. To what extent do these schemes successfully balance the competing water demands of urban industrial centers with the traditional livelihoods of downstream rural communities?