Real-time Monitoring of Water Quality in the Ōtākaro-Avon River Catchment
Adroit has installed a real-time sensor network in the Ōtākaro Avon River that will give Christchurch City Council an unmatched insight into the water-quality in this important waterway.
Ōtautahi Christchurch is home to some of the purest drinking water (wai māori) in the world, drawn from deep aquifers situated below the city, flowing from the mountains of the Southern Alps (Ka Tiritirio-te-moana), to the sea.
Part of this journey sees this pristine water flow down the Ōtākaro Avon River which extends for 26 kilometres from its spring-fed source in Avonhead to the mouth at Te Ihutai Estuary.
But here it is subjected to the impacts of over 100 years of extensive urban and surrounding agricultural development, river and stream bank modification, stormwater input, earthquake damage and other human interventions.
In response, the Christchurch City Council is working to begin to understand the water quality in the Ōtākaro Avon River Catchment and to take action to return it to its pristine condition.
Michael Healy, Smart Christchurch Manager at Christchurch City Council says the Ōtākaro Avon River has always played an important role in the history of the region.
“Historically the Ōtākaro Avon River was an important source of mahinga kai for early Ngai Tūāhuriri and colonial pioneers. Unfortunately, development and urbanisation has diminished the quality of this once pristine waterway.
“The Council’s goal is to help restore good quality water. A healthy waterway provides a place for the whole community to swim, fish and enjoy the environment.
“A lot of work still needs to be done to achieve this. Smart Christchurch is looking to new technologies to help reverse the damage that has been done over the last 150 years, and improve the water quality of the Ōtākaro Avon River for future generations,” he said.
As part of its Smart Christchurch programme Christchurch City Council put out a request for proposal to install new smart technologies and sensors in the Ōtākaro-Avon River, with the objectives of:
- Providing greater insight on water quality and potential impacts from contamination and weather events
- Providing real-time environmental datasets and conditional alerts/warnings to inform management and remediation activities across agencies
- Collaboratively advancing knowledge and the stewardship of fresh water across the community.
The Christchurch City Council already monitors river water quality, but this has largely been done through monthly grab sampling from 47 sites across the city – 13 of which are located on the Ōtākaro-Avon River.
The Smart Christchurch project will pave the way for a future move from manual ‘grab testing’ to sensor-based testing, due to traditional manual water quality monitoring being time-consuming and expensive. In manual testing water samples are sent to laboratories for analysis, with up to a two-week delay. Also, urban streams and stormwater networks experience particularly variable water quality, due to rapid run-off of water from roads and paved surfaces after rain.
So, Christchurch City Council was seeking a continuous water quality monitoring solution that allows for the capture and characterisation of water quality variation that might otherwise be missed, and determining improvements in water quality over time as remediation projects are undertaken.
Initially, both processes will run in parallel, which will enable the Council to measure the efficacy of the new real-time sensors in comparison to a grab sample.
The key benefit Healy is hoping to see from the introduction of Adroit Water Quality Monitoring is the ability to see pollution events unfold in real-time, and potentially take preventative action.
“And longer term as we do more riparian planting and other waterway enhancing initiatives, we can track the efficacy of those intervention methods and see how we’re doing in real-time with the health of our rivers,” Healy says.
The water quality in the Ōtākaro-Avon River is typical of those in an urban environment, with the collective impacts of stormwater inputs, waterfowl and stream modification contributing to both historic and current-day contamination.
Unsurprisingly, the best water quality is in the headwaters of the catchment, but downstream sites generally are more polluted with nutrients such as nitrogen and phosphorus, faecal contamination (E. coli), dissolved metals (zinc, copper), suspended sediment and turbidity.
High concentrations of these contaminants can impact the ecology of the river, as well as degrading recreational, cultural and amenity values.
Independent expert water scientist Phil Clunies-Ross, was engaged to advise what sorts of pollution types should be monitored, what types of technology should be used, and then – with only the ability to do four sites for now – which four representative sites would provide the widest possible view of what’s happening within the wider catchment.
Four sites were chosen for the first stage of the project:
- The Riccarton Drain, Addington Brook and Dudley Creek, reputed for their poor water quality.
- The Avon at Gloucester Street has been chosen as a representative site of the Ōtākaro Avon’s water quality in the central city, as well as its significant engagement potential.
Healy says that the public visibility was an important factor in placement and a lot of consideration was put into this aspect.
“One of the main aims of this project is to engage the public and educate them on river health and also give a call to action to a community about the things they can do differently, or how they can contribute towards a healthier river.
“So having visibility of the sensors and the data is a key part of the longer term strategy. Conversely, having sensitive technology in a public space presented some risk as well.
“So part of the trial is to work out whether it is best to hide the tech away from people, or is it actually more beneficial in terms of public awareness, to have it in the busiest places. Time will tell,” he says.
Healy also says the environmental data from the sensors will eventually be able to be accessed by the public.
“Once we know the devices are calibrated and everything’s working as we expect, then we can take that data from Adroit and then think about how we can present it in the most appealing way. There are lots of different ways you can do that – not just the data itself, but the context around the history of the river and the type of species that live there and how climate change may be affecting the river.
“Those sorts of things we can incorporate when we share with the public, to make sure we make the most of the opportunity and don’t waste it by just focusing on data without context,” he said.
“We can do this ultimately by looking to the past when the river was in the healthiest state, and then we can almost build a picture of what the future needs to look like and we can think about how we can work towards that,” he says.
The Adroit Solution
Adroit’s Environmental IoT monitoring solution for the Ōtākaro-Avon River was designed with input from the Smart Christchurch team and working alongside Phil Clunies-Ross.
Adroit installed four monitoring stations including a Libelium IoT controller connected to an In-Situ sensor, measuring temperature, conductivity, dissolved oxygen (DO), oxidation-reduction potential (ORP), pH and turbidity. Each monitoring station is powered by its own solar panel, takes water measurements every 15 minutes and uploads the data to the Adroit Cloud Platform via the Spark Cat-M1 Network.
The environmental data can be visualised at any time on any connected device and triggers are being set up to notify stakeholders of contamination events as they happen.
Adroit South Island Business Development Manager, Maria McIntyre says that each location presented its own challenge, varying from being at the edge of a public park, to the edge of a private property adjoining the river.
“There were a number of parties involved to get the locations set, so we had to do extensive site visits. The Heritage, Parks and Recreation teams were all involved. We had to really pick and choose where we were going to install,” she said.
McIntyre says that the Adroit team is incredibly proud to be able to work with the city on a project that has such a direct impact on the public.
“I don’t think a project has ever been done in a river of such historical significance in New Zealand – one that’s so central to the region and that runs through a city. This is a real push for connection back to the river and giving, I think, a real time view of what’s happening,” she said.
The Council’s Smart Christchurch project goes beyond water monitoring and an interesting aspect of this installation is how it will be required to interact with other technologies and communities over time.
For example, the Council is looking at a number of innovative solutions including the eClean Bioreactor – two of which have been installed in stormwater basins in collaboration with a local startup. These use microbes to remove contaminants from river water. The Adroit solution will be used to monitor the water quality and the success of these devices.
“We are also looking to use Adroit’s data to coordinate the activity of ECan with the not-for-profits which are already doing really good things within individual catchments,” Healy says.
From an urban waterway perspective, Healy says things are “looking positive,” but is keen to keep on pushing the limits of innovation, and collaboration.
“The Adroit team’s very energetic. They’re passionate about what they do and I think energy and passion goes a long way.
“For all of us, this is relatively new technology and we’re all learning on the job. So, it is a journey. And I’d like to think lessons learned from this implementation would be useful for future implementations. As hopefully we can expand the network, we can get more efficient and smarter about how we do it,” he says.