Timaru Herald: Land use impact on water ‘not known for decades’

Gerald Piddock writes in the Timaru Herald about groundwater – scientists say that the impact on our groundwater of intensive agriculture might not be known for decades, as it could take that long for any contaminants to reach monitoring sites.

While effects on shallow groundwater might be seen fairly rapidly, effects on deep groundwater would take longer to see.

See here for an SMC briefing on groundwater.

An excerpt: (read in full here)

“However, this did not necessarily mean intensive land use had no impact on water quality. “The water being monitored today is actually a reflection of land use that might have taken place decades ago and some distance away from that monitoring point.”

“He could not say what activities led to increased levels of nitrates because there was no statistical evidence in national or regional monitoring networks to describe the relationship between groundwater quality at a site and land use around that site.”