Fig. 2. Runoff hydrographs for 2-yr (Event 2) and >50-yr (Event 11) return period events in relation to daily rainfall for a beef cattle feedlot in southern Alberta. The hydrographs for west and east alleys for Event 11 on 8 June 2002 are incomplete because water in the catch basin rose to the level of the weir, and runoff could not be measured thereafter. Note that the scales for the y axis are different for Events 2 and 11.