Conserving water on campus
The water we use
UC is connected to the Christchurch City Council’s mains water supply. As stated on the Environment Canterbury Regional Council website, Christchurch has a plentiful supply of fresh clean drinking water. Christchurch’s aquifers are replenished with 375 billion litres of water each year, most of which is not used and flows out to sea.
Additionally, UC has progressively been installing ground source heat pumps (GSHPs) to allow heating to new buildings and is currently retrofitting them to efficiently heat as many existing buildings as possible. GSHPs work by using subterranean aquifer water as a heat exchange medium, extracting only low-grade heat from the water which is then returned/reinjected back into the aquifer. The heat pump then circulates heated water in pipework throughout the buildings to individual heat-exchangers (radiators and air handling units). The GSHP is an efficient provider of heat energy because of the use of low-grade heat from aquifer water, so the amount of heat transferred into the occupied space is often at least 3 times that of the input electrical energy to the GSHP, which is known as Coefficient of Performance (CoP).
Water is used on campus for a wide range of purposes including for drinking water, in bathrooms, in many lab practices, to provide air cooling in most buildings, and to irrigate the campus grounds.
Since 2016, total site water-use data has been available, and year on year comparative analysis is undertaken, and is reported in the annual Sustainability Report.
Individual buildings at the Dovedale site are not yet metered. Dovedale site has only one water entry point, which is already metered.
What happens to the water we use?
All water used within buildings, except for air-cooling water, goes to sewer or trade-waste for treatment.
Water piped through buildings to cool the indoor air temperature is then discharged into waterways running through the campus: the Ōtākaro/Avon river and Waiutuutu/Okeover Stream. The air-coolant water is a few degrees warmer than natural spring water, but otherwise has high water quality, with no chemicals added to it. Facilities Services monitors one site along Waiutuutu/Okeover Stream, including water temperature and flow rate from air-cooling outflow pipes.
Water that goes into drains in carparks, roads, and building down-pipes flows straight into our campus waterways. Several student research projects from the Natural Resources Engineering programme have examined aspects of stormwater quality and volumes flowing into Okeover Stream as part of the waterways restoration project.
Wastewater
Strict environmental standards govern the discharge of wastewater from UC sites, managed in Christchurch and the wider Canterbury region by Environment Canterbury and the Christchurch City Council via resource consents.
UC’s wastewater is treated via the Christchurch City Council’s wastewater treatment systems. This is comprised of a network of 239 pump stations, all feeding to the treatment plant in Bromley. After proceeding through screens, grit removal and sedimentation tanks, the water is aerated in tanks and basins and then sent through clarifiers into six oxidation ponds which destroy harmful bacteria and viruses using natural processes. Finally, the water is discharged into Pegasus Bay three kilometres offshore via an ocean outfall pipe buried eight metres below the sea floor.
The Christchurch Wastewater Treatment Plant’s Environmental Statement ensures that the Christchurch community is provided with ‘a safe and healthy environment through the appropriate treatment and disposal of its wastewater’.
Water-conscious planting and management
UC has targets to increase canopy cover by planting more trees, particularly in areas of bare lawn. This canopy cover target will improve biodiversity and other ecosystem services, namely cooling, as well as reducing water loss and will assist with flood mitigation and water quality. UC is also using plant landscapes and management techniques to minimise water useage. Examples include:
- Mulching: UC's campus gardens are mulched to retain soil moisture and evaporation. Plants are selected by identifying dry and hot north facing borders, compared to cooler shady south facing borders. 70% of the mulch is produced on site from UC Campus green waste.
- Xeriscaping (eg. the use of drought-tolerant plants): Endemic locally sourced native planting have been selected which have evolved to survive in the area. This requires no annual or perennial plantings, with the exception of the wildflower meadow trials.
- Irrigation: Frequency of irrigation to lawns is reduced during summer by deep irrigation mythology to encourage deep root growth. Irrigation is automated to operate from 11.00pm to 7.00am to reduce evaporation, and soil moisture levels are monitored to ensure efficient use of UC's water resource.
- Grass cut height: Cut height is raised to develop an increase in grass root depth and reduce evaporation by shading the soil.
- Lawn clippings: Clippings are not collected to allow for reduced evaporation by holding moisture in the soil.
UC has a landscape master plan that includes a commitment to planting species for their ability to filter and cleanse water. Learn more about UC's canopy cover targets by reading UC's Biodiversity Plan here.
What can you do to support water conservation?
Facilities Services is using building water monitoring to identify opportunities to reduce water consumption as staff time permits.
You can help reduce water use and keep our waterways clean by:
- Notifying Facilities Management (extn. 6400) if you notice a water leak on campus.
- Being mindful of water use in any lab activities.
- Ensuring that if you are working or playing outside, that you tip any contaminated water into a sewer drain (i.e. take it to an indoor sink, or to one of the few designated wash-down drains outside). Only rainwater should flow into the "stormwater" drains in roads, carparks, and building down-pipes.
Refill your water bottle
Bottle fillers are available on drinking fountains at the following locations:
- Central library (James Hight building), by the lifts on all levels
- Engineering Core (outside E6)
- Rutherford building (Chemistry/Physics), by the lifts on all levels except the ground floor
- Science Library, by the main entrance
- Kotuku building, in entrance foyer
- Education library (Henry Field building), outside the NZ Room and Level 2 outside the toilet block
- Recreation Centre
- Wheki building, in all main corridors
- Haere-roa
- Beatrice Tinsley Bike Park (outdoor)
Download the Sustainability Pocket Map to see the most up-to-date location of campus drinking fountains.
