Task Sheet: River Discharge and Regimes

1. Define the term discharge.

2. Copy the most commonly used formula for calculating discharge into your notes.

3. Define the term simple river regime.

4. Describe and explain the river regime for the River Rhone of Glelsch and the River Thames.

5. Describe the contrast of the river regime for the River Rhone of Glelsch and the River Thames.

Task Sheet: Storm Hydrographs

1. How does a storm hydrograph differ from that of a graph showing a river regime?

2. Define the following term.

Peak rainfall Baseflow Rising limb

Peak discharge Storm flow Falling limb

Lag time Bankfull discharge

3. Calculate the peak rainfall, peak discharge and lag time for the flood hydrograph below.

Peak rainfall =

Peak Discharge =

Lag time =

4. Using the hydrograph on the next page calculate the discharge need for the river to flood.

Discharge required to flood =

5. Calculate how many hours it took the river to return to base level flows.

Hours until base flow returned =

6. Explain which flows from the drainage basin contribute to storm flow.

7. Define the following terms; infiltration capacity and infiltration rate.

8. Describe and explain what conditions can lead to overland flow.

9. Describe the main trends for discharge that the hydrographs shows. Make sure you use the terms you have calculated above.

10. There are two main shapes that hydrograph can follow, the graph below shows both. You can see that Hydrograph A (blue) has a completely different shape than hydrograph B (red).

Describe how the shape of hydrograph A differs from the shape of hydrograph B. Make sure you refer to lag time and peak discharge.

11. Describe the main factor that controls the scale of peak discharge recorded by storm hydrographs.

12. Describe the main factor that controls the length of the time lag recorded by storm hydrographs.

13. Produce a report to describe and explain how the following affect storm hydrographs. Use your textbook and the PowerPoint to help you. Try and include as many geographical examples to back up your answers.

Intensity of precipitation(high or low)

Duration of precipitation(short or long)

Type of precipitation(snow)

Temperature(high or low - ET)

Type of soil(thin or deep – air space and grain size)

Type of rock(impermeable verses permeable or porous)

Size of drainage basin(small verses large)

Shape of drainage basin(round verses elongated)

Vegetation(different types – summer verses winter)

Land use(agricultural verses urban)

Urbanisation Human Intervention

14. Complete the following task below.

15. Complete the following task below.

16. Complete the following task below.

17. Describe and explain the different shaped hydrographs shown below.

Notes for Water BalanceEquation of the water balance

Define and explain soil moisture recharge, soil moisture surplus, soil moisture utilisation and soil moisture deficit

Why do they occur?

Notes for Drainage BasinDefine the terms drainage basin and open system.

Define the terms inputs, stores, transfers and outputs.

Make a list of the terms that you need to learn and briefly define them.