Marae water usage monitoring update
NIWA has partnered with ten marae around the North Island to monitor water (as a surrogate for wastewater production) and marae usage.
The project seeks to refine design assumptions for water and wastewater system designers, and enable the potential benefits of a range of innovations to be assessed (e.g., installation of water-efficient showers, toilets, taps and appliances, and separate treatment of blackwater and greywater).
Monitoring at some marae has been underway for over 12 months while at others it has only recently started. Interim monitoring results from three marae show a good correlation between water use and marae occupancy (Figure 5). The monitoring results illustrate the extreme variability in marae usage, with little to no usage occurring for extended periods of time coupled with short periods of high use.
Typical wastewater system design guidelines suggest per capita wastewater generation of 40 litres per person per day (l/p/d) for day-only marae users and 150 (l/p/d) for day and overnight marae users. While limited conclusions can be drawn at this early stage, it appears that actual per capita water usage, and therefore wastewater generation, is lower than typically assumed in marae water and wastewater system design.
The initial monitoring results suggest that existing design guidelines need to be reviewed and confirms the benefits of recording marae occupancy and measuring water use to inform better water system management and design. The findings of the monitoring programme will be published following analysis of all data from the monitoring project.
Colliar, J.M., Sukias, J.P., Tanner, C. Stott, R. Bellingham, M. (2015) A marae water use monitoring network: Preliminary assessment of water use. New Zealand Land Treatment Collective Conference 2015, Wanaka, New Zealand 25 – 27 March.