The Leith Flood Protection Scheme mitigates the risk of flooding to an area of approximately 200 hectares extending from Malvern Street in Glenleith to Rattray Street in the Dunedin CBD.

The Water of Leith catchment to the north of Dunedin’s CBD is approximately 42 square kilometres. The scheme provides some protection for key Dunedin infrastructure such as the existing and new Dunedin Hospitals, the University of Otago, Otago Polytechnic Te Pūkenga, and Forsyth Barr Stadium. The upper section of the catchment and its tributaries (including Lindsay Creek, which flows through North East Valley) are relatively steep compared to the flatter lower reaches, allowing floodwaters to rise quickly.

Before the 1929 Dunedin flood, concrete and stone walls had been built along the banks of the river to prevent erosion and enable better use of adjoining land. The Otago Harbour Board built a concrete channel from Forth Street to the harbour in 1913-14.

After the 1929 flood, the concrete channel was continued from Forth Street to the harbour. Concrete and stone walls along the channel were strengthened and raised.

The Dunedin City Council extended the channel upstream from Forth Street in the early 1950s, then built a high-velocity concrete channel later that decade to straighten the Water of Leith. Boulder traps were built upstream of George Street, and a larger boulder trap was built upstream of the lower Malvern Street bridge in the late 1960s.