Canterbury region

Canterbury, as the largest region in New Zealand, has the largest water resources and also the highest water use.  It is estimated that around 70% of irrigated land in New Zealand falls within the Canterbury region.  Groundwater is used extensively for irrigation and drinking water supply across the Canterbury Plains and in other inland basins. 

The majority of surface water is found in 7 major alpine rivers (Waitaki, Rakaia, Waimakariri, Waiau, Rangitata, Hurunui and Clarence).  These rivers come from high rainfall areas in the Southern Alps, often with extensive snow and ice fields sustaining flows through the summers.  These rivers are also an important source of groundwater recharge for the Canterbury Plains.  Smaller rivers derive from the foothill mountain ranges (e.g. Pareora, Opihi, Orari, Selwyn, Ashley, Waipara and Conway rivers) which are lower rainfall areas and the rivers often reach very low flows in the summer. 

A third set of rivers and streams are the groundwater derived spring fed streams found near the coast (e.g. Ohapi Creek, Harts Creek, Avon, Styx and Cam Rivers).  These spring fed streams sustain flows through most summers but are also the most affected by extensive groundwater usage.  Water allocation is managed in Canterbury through the region-wide Land and Water Regional Plan and a series of sub-regional chapters which set out the allocation regime (i.e. minimum flows, total volume available etc.). 

The planning framework is underpinned by the non-statutory Canterbury Water Management Strategy (CWMS) which divides the region into 10 water management zones and are run by Water Management Zone Committees.  The CWMS sets out a series of economic, social, cultural and environmental targets, including improving water quality in lowland streams and increasing irrigated area across the region.