Marae water usage project
As part of the ongoing research project, NIWA has extended the marae water usage monitoring programme to include a further eight marae. The marae are all located in the North Island and include marae from Te Taitokerau, Tainui, Maniapoto, and Te Moana ā Toi.
What is this monitoring programme for?
The long-term aims of the project are:
- To better inform system designers and help refine or establish (if necessary) improved design assumptions for marae water and wastewater systems (e.g., improving water use efficiency; separating greywater from black water and treating greywater in innovative ways, thus reducing the load on existing wastewater systems).
- To better understand potential wastewater flow reductions from a range of behavioural and physical system initiatives, and to feed into other aspects of the overall research project.
A direct and immediate benefit of the monitoring is to help identify significant leaks in the marae plumbing and fixtures and quantify how much water was being wasted as a result, which in turn allows for repairs to be undertaken.
What design advice is available for marae currently?
There is very limited design advice provided for marae wastewater systems.
The New Zealand Standard for onsite domestic wastewater management (AS/NZS 1547: 2012) provides typical domestic wastewater flow allowances for commercial premises in New Zealand (including motels/hotels; community halls; and camping grounds), but no guidance for marae wastewater design.
A number of district and regional councils provide guidance on marae wastewater generation assumptions, including Horizons Regional Council, Gisborne District Council, and Auckland Council. TP58 (Auckland City Onsite Wastewater System Design and Management Manual, 2004) provides the following advice:
Day only visitors
40 litres per person
Day plus overnight visitors
150 litres per person
The TP58 flow figures assume that lunches and lunch/dinners will be served, and that overnight visitors have access to showers but not to laundry facilities. TP58 also advises that “Water meter readings should be installed to provide added certainty to the accuracy in the design flow allowance.
What is involved?
A number of flow meters are installed at specific locations on the marae potable water system (see photo for example water meter installation). The flow meter data is either transmitted (via telemetry) back to NIWA, or saved locally for periodic downloading. These installations provide real- time data on water used and therefore wastewater generated by the marae.
Each marae also keeps a record of marae usage to accompany the water-flow monitoring, and submits the information back to NIWA:
- Type of Event (e.g., marae hui, tangihanga, birthday, working bee).
- Duration of event.
- Numbers booked for event.
- Estimated actual numbers in attendance:
- Day only visitors.
- Day and overnight visitors.
Both the marae water usage monitoring and recording and marae usage/occupancy data are critical to the success of this monitoring programme.