Table 2: Estimates of extreme floods at Gasper Lake. FM = non-linear flow model Method Inflow Outflow Peak level (m OD) Head over crest (m) Head with wave surcharge (m) (m3 s-1) (m3 s-1) FEH/PMF 86 86 131.96 0.86 1.18 Transposition of 49 48 131.67 0.56 0.88 Martinstown storm Trans. & max. of 70 70 131.86 0.76 1.08 Martinstown Storm Trans. Using 68 68 131.84 0.74 1.06 Non-linear FM Trans. & max 94 94 132.03 0.93 1.25 Non-linear FM PMP/PMF 146 146 132.28 1.18 1.5 Flood frequency 150 150 132.3 1.2 1.52