Source protection zones for drinking water catchments

The canal and stopbanks of the network on the Hauraki Plains. Photo / WRC

The recent drinking water contamination in Havelock North which caused the deaths of four people and made thousands seriously ill has been a wake-up call.

Many of Thames Coromandel's drinking water supplies, including those in Pauanui, Whitianga, Whangamata, Tairua, and Thames have failed Health Act and drinking water standards (Annual Report on Drinking Water Quality 2018–2019 by the Ministry of Health).

New Zealand drinking water-related gastrointestinal illness has been estimated to be between 18,000-35,000 cases per year.

Local and Havelock North experience has shown that it was not safe to rely on conventional water treatment and chlorine disinfection as this was often ineffective.

Central government's response has been to promote major reform of the way that our drinking water supplies and catchments are managed by district and regional councils.

There will now be a dedicated drinking water regulator, Taumata Arowai, and reform of the National Environmental Standard for Sources of Human Drinking Water (NES-DW).

Much stricter regulations will now control how district council's manage drinking water treatment plants and regional councils must enforce stricter controls in drinking water supply catchments.

The major change in the NES-DW is a requirement for Waikato Regional Council (WRC) to establish formal source protection zones for drinking water supplies. WRC must also publish information on the quantity and quality of source waters and information on land-use activities and potential sources of contamination.

This will have major implications for the Waikato region.

A recent Massey University study has confirmed that agricultural catchments with cows, sheep and deer had a high prevalence of cryptosporidium, giardia, campylobacter, and E. coli. Those draining native forest catchments had little if any pathogens.

The

Massey study concluded that there should be a limit to agriculture intensity and/or to utilise riparian vegetation buffers...

Denis Tegg, Thames-Coromandel Representative for WRC

to help reduce the prevalence of pathogens in many waterways.

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