Table 1: Key parameters

Parameter Units Value
Existing (2009 survey) After raising
Catchment area km2 2.57 No change
a) permanent impoundment m3 106,000 No change
b) controlled flood storage m3 Nil 233,000
c) Total m3 106,000 339,000
Surface area at overflow level m2 68,000 No change
Crest of non-overflow embankment mOD 88.02 91.10
Maximum storage level mOD 87.02 89.72
River Bed level mOD 80.8 No change
Dam height above stream bed m 7.4 10.5
Diameter of orifice to attenuate flood flows m N/A 0.35