Results show that although errors associated with parameter extraction methods may cause significant changes in lag time values, the errors become less significant once entered into a model to calculate discharge. Table 6.1 shows that lag time is inelastic with respect to longest flow path (LFP), as the elasticity of lag time with respect to this parameter is 0.8. Discharge is also inelastic with respect to longest flow path, with an elasticity of –0.22. This last number, discharge elasticity with respect to longest flow path, was determined by multiplying the lag time elasticity with respect to longest flow path by the discharge elasticity with
respect to lag time calculated using the value of 0.14.
(-0.28). The same method as
discharge elasticity with with longest flow path, is
respect to slope, also inelastic at a
Flow path and slope values were originally thought to be large contributors to lag time variations. This analysis shows that this is not necessarily
the case. both slope
Table 6.1 shows that SCS lag time acts and longest flow path (-0.50% and 0.80%
inelastically with respect to respectively). Once entered
into a hydrologic model, discharge, with discharge
variations in these parameters have minimal effect on elasticities of 0.14% and –0.22% respectively. Thus, a
1% variation in slope will cause a variation in longest flow path will
minimal 0.14% increase in discharge, cause a 0.22% decrease in discharge.
Table 6.1 shows that curve number, unlike slope and longest flow path, has an elastic effect on lag time. The lag time elasticity with respect to curve number is -3.52. Discharge is also elastic with respect to curve number (at an