Historic Freshwater State
Surface Water Quality
Surface water, being above ground waterways, are easily recognizable across the Marlborough landscape – such as our iconic braided rivers. Surface water courses gain their flow through catchment areas as well as underground springs in some cases. A catchment is the area of land from which all rainfall and streams flows out into a river, a lake or the sea. The catchment of large rivers, such as the Waiau-toa/Clarence River, can be divided into smaller sub-catchments, which usually represent the tributaries.
The Surface Water Quality State of the Environment (SOE) monitoring has been operational in Marlborough since 2007. The programme measures 56 sites regionally. This FMU has historically not been included in this monitoring due to access and resourcing restrictions.
Ground Water Quality
Knowledge of groundwater in the Waiau-toa/Clarence FMU is limited, but the geology of the area prevents extensive aquifers like those of the Wairau. Some water is likely to be stored in the glacial and outwash gravels and river-borne gravels and silts in the valley floors and basins.
Historically there has been minimal demand for water abstraction in this area, primarily limited to minor domestic and stock supply. There have been minimal resource consents issued since the RMA 1991 in this area.