The same steps were taken to determine the effect of drainage area on discharge as were taken to determine the effects of lag time on discharge. For each return period, the percent variation in discharge was calculated based on the

percent percent period

variation in drainage area (1.80%).

# There

discharge for each was calculated by

return period. dividing each

Discharge discharge

were slight variations in elasticity for each return variation by 1.80% (the

variation in drainage area). There return period. These numbers were elasticity, as shown in Table 5.18.

were slight averaged to

differences in elasticity for each provide an approximate discharge

Elasticity

Elasticity

Elasticity

Elasticity

Elasticity

Elasticity

Q_{2}-Area

Q_{5}-Area

Q_{10}-Area

Q_{25}- Area

Q_{50}- Area

Q_{100}- Area

Q_{2 }

Q_{5 }

Q_{10 }

Q_{25 }

Q_{50 }

Q_{100 }

Elasticity

2.05%

1.74%

1.60%

1.96%

2.09%

1.99%

Q_{avg}-Area

# Table 5.18: Discharge Elasticity due to Area Variations

1.14 0.97 0.89 1.09 1.16 1.11

1.91/1.80=1.06

The resulting elasticity of discharge with respect to area is 1.06. Hence, a 1% increase in area yields approximately a 1% increase in discharge, as one would expect.

# 5.2.2.4 Step 2 Results

Results from the numerical calculations of gradient show that there is a constant, inversely proportional, relationship between lag time and discharge.

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