The current state of our freshwater
Te ora o ō tatou wai māori i tēnei wā
Land development and freshwater management over generations has had an enormous impact on water quality and freshwater ecosystems in Te Taitokerau.
While modern land use and development practices have improved, we are still dealing with the legacy of deforestation, loss of wetlands and land drainage.
Our biggest problems are the high levels of sediment and Escherichia coli (E. coli)1 in our freshwater, and a lack of riparian vegetation to support healthy ecosystems.
Sediment
High levels of sediment in our streams, rivers and lakes make our estuaries muddier, waterways less appealing to swim in, and make it harder for native plants and animals in the water to survive.
E. coli
E. coli is an indicator for bacteria and viruses in the water that can make us sick. The higher the levels of E. coli, the greater the risk of getting sick when swimming in or drinking untreated water.
Lack of riparian vegetation
Plants and trees along the water margins and banks (riparian vegetation) are essential for healthy waters. They provide the cool, shady habitats freshwater ecosystems in Aotearoa New Zealand need.
How does the health of our waterways measure up?
Under the Government’s policy direction (NPS-FM) (PDF 1MB), we’re required to set baseline states for the 22 compulsory freshwater attributes (PDF 1.1MB), such as water quality, physical habitat, or levels of E. coli, for example. An attribute is essentially something we can measure and monitor and which tells us about the state of a freshwater system.
We have used data from 2015-2019 to determine the baseline state for most of the compulsory river attributes and 2016-2020 for the compulsory lake attributes. We have also included a few extra attributes that we think are important to Northland. There are a few attributes where we have yet to collect enough information to determine the baseline state.
Northland freshwater baseline state evaluation report
This report describes the attributes and associated methodologies used to derive the baseline states for Northland freshwater bodies including rivers, lakes, wetlands and groundwater aquifers where sufficient data available.
1 Escherichia coli (E. coli) is a bacteria used to measure faecal contamination in waterways. Although there are very low levels of naturalised E. coli in our waterways that are not associated with animal or human faeces, these have little effect on E. coli measures (Moinet M., et al. (2021). Faecal source tracking and the identification of naturalised Escherichia coli to assist with establishing water quality and faecal contamination levels. AgResearch, Palmerston North. Available from: ourlandandwater.nz; and Muirhead R, Hudson R, & Cookson A. (2023). A review of river microbial water quality data in the Northern Region. AgResearch. Available from: www.nrc.govt.nz).
Find out more about water quality in Northland’s rivers and streams
Wetlands used to cover around 20% of Northland. Today, the remaining wetlands are fragmented and cover only about 5% of Northland’s land area. While we have data on some of these wetlands, we don’t have enough to give the full picture on the state of our wetlands. So, we are in the process of developing a wetland monitoring programme to provide us with an assessment of the wetland baseline state across the region.