River flows or lake levels monitoring is integral to understanding habitats, flooding frequency, severity and extent, effect of a range of water uses and behaviour of river/lake beds, which will all assist regional councils for effective catchment and water management.
Councils monitor all major river and lake systems for flows and levels. If minimum flows (or levels) are imposed through plans, automated flow monitoring is established at all minimum flow sites which will assist councils and resource consent holders to ensure compliance with the minimum flows.
Minimum flows or levels are set through councils’ consultation and planning process. Minimum flows/levels ensure river or lake habitats are maintained. Much of the abstraction of water (e.g. irrigation) is ceased when flow or level drops below the prescribed level.
Water quality monitoring is also essential for the effective catchment management and water management. Long-term water quality monitoring enables to understand trends. Water quality indicators have to be selected carefully to assess impacts.
As for freshwater quality key physico-chemical indicators such as pH, conductivity, temperature, clarity, suspended solids, dissolved oxygen, total nitrogen, nitrate nitrogen, ammoniacal nitrogen, dissolved reactive phosphorus, total phosphorus, faecal coliforms or E.coli are monitored regularly, at least once a month.
At selected sites freshwater biology (e.g. invertebrates and algae) is also monitored. Basic state of the environment water quality can be viewed on LAND AIR WATER AOTEAROA managed by all regional councils collectively.
Most key estuaries are also monitored similar to river systems. However, there is only limited monitoring of the coastal waters. Much of the coastal monitoring is related to faecal bacteria monitoring for bathing water quality monitoring.