Exercise 4: Effects of land-use change

1) Calibrate the HBV-model to the Norrsjön catchment 

Change the following parameter in order to simulate the runoff as good as possible: TT, CFMAX, SFCF, FC, BETA, LP, K0, K1, K2, PERC, UZL, MAXBAS. Make a note of each change of a parameter value and its effect to the simulation. Three elevation zones (Table 1), but only one vegetation zone are used (lake percentage: 2 %) (check WORK-Catchment data). Use the period 730901 to 820831 for calibration ('warm up' from 720101). 

Stop the calibration after about 2 - 2.5 hours: 

Write down your final parameter values and the model efficiency (Reff) you achieved 

Table 1 

Min. [masl] 

Max. [masl] 

Fraction 

350 

400 

0.14 

400 

450 

0.56 

450 

520 

0.30 

Elevation of the climate station: 250 m a s l 

(PCALT=10%/100m, TCALT=.6°C/100m) 

2) Land use change

Between 820831 and 850831 the area with clear cuttings in the catchment increased from around 10% to above 20%. Run the model for the period 810901 to 910831 (with your parameters from 1) ) and look on the differences between simulated runoff (supposed to be the 'real' runoff without the increase of clear cuttings) and observed runoff. Discuss the effects of the land use (850831 to 910831) change on : 

  • water balance 
  • runoff during different seasons 
  • runoff during high flow conditions 
  • runoff during low flow conditions 
  • spring flood (volume, peak) 
  • peak runoff during autumn 

Exercise 5

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