Which water route commonly gives a river a rapid response to a storm?

• Groundwater travelling through deep rock and sediment
• Throughflow travelling through water-filled soil spaces
• Surface runoff moving towards a channel

Surface runoff enters a tributary within a drainage basin. Which river system does that tributary feed?

• The river system draining that basin
• A river system across the surface divide
• Every river system in the surrounding region

A drainage divide separates the surface drainage of neighbouring river basins.

Circle one:   True   False

During gentle rain, most water infiltrates and little runs over the surface. The river rises slowly. Which explanation is best supported?

• Gentle rain sets the response speed regardless of the water's route
• Water reaches the river by slower soil and groundwater routes
• A slow rise proves that a large lake stores rainfall within the basin

After a storm, river discharge rises rapidly and peaks soon after peak rainfall. What does this show?

• A slow response that cannot cause any flooding
• A rapid response with a short rainfall-to-flow lag
• A long delay identifying groundwater as the only route

Covering soil with impermeable concrete increases infiltration into that soil.

Circle one:   True   False

In both basins, peak rain occurs at noon. Peak discharge is at 1 pm in A and 6 pm in B. What comparison is supported?

• A has a longer lag and must contain more groundwater
• A has a shorter lag and reaches peak discharge sooner
• B has less flood risk solely because its discharge peaks later

An estate adds impermeable paving and drains storm water directly to a river, without storage. Why might flood risk increase downstream?

• Reduced infiltration sends runoff quickly to the river
• The drains store storm water until groundwater levels fall again
• Paving increases infiltration and delays the river's storm response