Southland region

The Waihopai River and its tributaries have been greatly modified over the years. Formerly a sinuous stream that meandered across its floodplain, the Waihopai now flows through straightened channels and is constrained between flood banks, especially in its lower reaches. A flood retention dam has also been built on the outskirts of Invercargill city to hold back large flow events from flooding low lying urban and industrial surrounds. Original land cover in the Waihopai catchment undoubtedly consisted of large wetland and bog areas with large expanses of native bush as well. This has largely been drained and cleared to produce the productive farm land seen today. Apart from the Waihopai River catchment itself, a large tract of the Waihopai surface water zone is basically an unmodified wetland area. This includes the internationally significant Waituna wetlands on the Awarua Plains. There are a number of small streams that drain the Waihopai zone. Two of these creeks, the Otepuni and Kingswell, flow through Invercargill city and have historically caused flood damage to the city’s infrastructure and residential property. Both creeks now are largely contained by major flood protection works including flood retention dams on the Invercargill city eastern boundary. Environment Southland has six permanent water level and three automatic rainfall recording sites. These sites provide flood-warning information and also other important hydrological information. There are currently low levels of surface water allocation in the Waihopai surface water zone.