LAWA (Land, Air, Water Aotearoa) has released a new online topic that shows the quality of New Zealand’s vital underground water resources. The Groundwater Quality topic makes monitoring data from almost 800 wells publicly accessible.
Environment Canterbury Scientist Carl Hanson is the LAWA Groundwater Quality topic Lead and said many people aren’t aware of the importance of New Zealand’s groundwater resources.
“Groundwater accounts for about 80% of all freshwater in New Zealand. It is used for drinking water, irrigation and industry, and it is a major contributor to rivers and streams.
“Regional councils and unitary authorities are responsible for monitoring groundwater quality and their sampling results are now available on the LAWA website. Looking at the data, most of our groundwater is of very good quality. However, contamination from E. coli and nitrate does occur in some wells and there are longer-term trends of degrading water quality in some areas.
“An important message to take away is that anyone using groundwater as a source of drinking water should make sure their well is sealed and have their water tested regularly,” said Mr Hanson.
Groundwater comes from rainfall and river water that seeps into the ground and flows through underground aquifers. Contamination can occur when harmful substances make their way down through the soil into the underlying aquifers. In coastal areas, excessive groundwater use can draw sea water into aquifers, a process called seawater intrusion.
Horizons Regional Council Groundwater Scientist Abby Matthews said once groundwater is polluted it can be very difficult to clean up.
“We have long term monitoring programmes to look for regional-scale changes in groundwater quality that could be caused by human activities,” said Ms Matthews. “This helps us manage those activities that can threaten groundwater quality, the people who use the groundwater, and the waterways that are fed by the groundwater.
“On the LAWA website, visitors can see state and trend info for groundwater sites on an interactive national map. Site state and trend have been evaluated for five widely recognised indicators of groundwater quality; these indicators are E. coli, nitrate, phosphorous, chloride, and electrical conductivity. Together they provide insight to the presence of pathogens, nutrients, and seawater intrusion.” said Ms Matthews.
Regional council and unitary authority staff regularly collect groundwater samples from across their regions following rigorous procedures, before sending the samples for testing by accredited laboratories.
“Groundwater is a critical part of the water cycle and maintaining its quality is essential for our health and economy,” said Chair of Local Government New Zealand Regional Sector and Bay of Plenty Regional Council Doug Leeder. He continued, “We know groundwater quality can be impacted by both rural and urban activities and we work with our communities to manage these risks.
“We hope that by making our monitoring data accessible on the LAWA website we can raise the profile of groundwater and equip locals, iwi, scientists, policy-makers, and industry with a useful resource. We must all continue to work together to protect this precious taonga.”
The LAWA Groundwater Quality topic features state and trend information for individual sites, and factsheets, videos, and a glossary to assist with interpretation.
LAWA is a partnership between New Zealand’s 16 regional councils and unitary authorities, Cawthron Institute, and Ministry for the Environment, with support from Department of Conservation and Statistics New Zealand.