Figure 5.6: Analytical Calculation of Gradients
As the longest flow path varies by 13.2%, the lag varies by 10.6% when evaluated at the base value for longest flow path (3.12 miles). The elasticity is then 10.6 ÷ 13.2 or 0.80. As this number is less than one, the relationship between longest flow path and lag time is considered inelastic, signifying that lag time is not sensitive to changes in longest flow path length. These results show that a 1% increase in longest flow path will cause a 0.8% increase in SCS lag time.