considerably from less than 5% to over 50%, depending on the nature of the event
and the terrace. Much of the inter-event variability on each terrace could be
accounted for by a combination of total rainfall and a measure of rainfall intensity.
Table 4 lists the statistical levels of explanation for a sample of terraces for 1993.
Total rainfall, in general, offered the highest level of explanation (53–80%) for runoff
variance of all the simple independent variables apart from for terrace 11. The EI15
composite index also offered a high level of explanation of between 54% and 82%.
Total rainfall performed better than EI15 as an explanatory variable on plots with
lower infiltration rates, and vice versa. The inclusion of rainfall duration as a second
independent variable with total rainfall further improved the explanation by up to
10%, but only on some plots (Table 4).