Environment Waikato has granted Hauraki District Council consents to take water to continue supplying the Hauraki Plains with potable water.
The District Council had applied for existing ground and surface water takes and structures and to de-silt an existing water reservoir near Steen Rd, Mangatarata. Seven submissions were received from neighbours and iwi.
A 300 millimetre high weir is used during summer months to raise water levels in the Mangatarata Stream. The applicant’s planning consultant requested a 10-year term, and asked for a requirement for a mesh on the intake pipe to be removed, along with a fish passage requirement at the Steen Road intake.
He said increased use of the bore field was not considered an option, as the quality was low and would need significant dilution with higher quality surface water to achieve reasonable drinking water standards.
The District Council was considering two alternatives for the long term supply of water to the Plains to avoid taking surface and groundwater during low flows, however a working alternative was still a number of years away.
Submitters were concerned that altering the height of the weir in winter would contribute to flooding and adverse effects on downstream property. One submitter said a negotiated agreement between the District Council, submitters and Environment Waikato to stop taking water from the catchment had been broken.
An Environment Waikato staff report said effects from de-sliting would be short term and could be addressed through sediment control measures, minimising the length of the works and timing them to avoid large rainfall events. Effects of the temporary weir were limited to October to April. Fish passage issues were largely avoided as a fish pass has been constructed at the weir and during peak migration periods the weir is not in place.
Granting the consents, the Committee said it was aware that the provision of water for communities was difficult with limited resources available, adverse environmental effects and potential competing uses. The District Council’s planning and budgeting of long-term use and upgrading of infrastructure was a positive step towards sustainable management.
Granting the consents was a matter of balancing existing community needs and expectations while avoiding, remedying or mitigating adverse effects. Once the storage facility was operating, the maximum abstraction rate from the Mangatarata Stream during low flow should be 30 percent of the current rate from the two pumps.
A seven year term was warranted, given the significant effects of the take from the Mangatarata Stream on the Waitakaruru River, it said. It was concerned that progress since 1999 for a solution to the high volume extracted during low flows had been slow, and additional conditions would provide certainty for the community and submitters.