Relevant Research reports
Relevant background research is available at the following links:
Curletts Rd waterway at Curletts Road opposite A&P Showgrounds. Flows into Heathcote River/Ōpāwaho.
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Toi tū te marae o Tangaroa
Toi tū te marae o Tāne
Toi tū te iwi
If we look after the waters and land around us, we will be looked after in turn.
Research
Environment Canterbury has recently completed two investigations relating to the health of Christchurch waterways.
Waterway health is generally assessed by looking at what aquatic life, e.g. fish and invertebrates, make up the ecosystem of the stream or river. The aquatic ecosystem is affected by many factors, including in-stream habitat, bankside vegetation, sediment quality and water quality.
Reports show that the water quality of the Avon River/Ōtākaro and Heathcote River/Ōpāwaho is poor. Water quality in the two rivers is affected by what happens in the waterways upstream.
Haytons Stream catchment water quality investigation
Between March and July 2009, the National Institute of Water and Atmosphere (NIWA) collected water quality samples from the Haytons and Paparua Streams in southwest Christchurch. These two streams flow through Hei Hei, Hornby and Sockburn and flow into the Heathcote River/Ōpāwaho.
This work is part of an Environment Canterbury project to improve the health of the Haytons and Paparua Streams. The main source of water entering these streams comes from stormwater run-off from commercial and residential property, as well as from roads.
Why Haytons and Paparua streams?
The Haytons and Paparua Streams were selected because they consistently show poor water quality based on long-term monitoring by the Christchurch City Council, and flow through land used for a mixture of residential, rural and industrial land purposes.
This poor water quality has downstream impacts as Haytons Steam flows into the Heathcote River/Ōpāwaho, which has degraded water quality with respect to sediment, nutrients, metal and bacteria. The Heathcote River/Ōpāwaho then flows into the Avon-Heathcote Estuary/Ihutai.
What was found?
Water at the headwaters of Paparua Stream has a low concentration of contaminants, but contaminants increase as the stream passes through the residential area and downstream of the industrial land use area.
Haytons Stream, which flows through a catchment of predominantly industrial use, had poorer water quality than Paparua Stream.
Click on the map below of Haytons Stream catchment which summarises the water quality.
Haytons Stream catchment water quality investigation (Report October 2009) [PDF 5.7MB]
How does this affect you or your business?
Business information pamphlet for Haytons and Paparua Streams [PDF 1.39MB]
Pollution Prevention Programme website »
Sources of Sediment Input into Cashmere Stream
The second investigation, undertaken in conjunction with EOS Ecology, looked at sediment sources along Cashmere Stream.
Why Cashmere Stream?
Cashmere Stream is a significant contributor of sediment to the Heathcote River/Ōpāwaho, which has longstanding and increasing issues with sedimentation and clarity.
What was found?
- The worst tributaries for contributing sediment to the Cashmere Stream are a mix of both hill and plains tributaries (see map) and include Hoonhay Valley Drain, Milns Drain, Dunbars Drain, Hendersons Road Drain, Penruddock Pipe, and Worsleys Drain (listed in an upstream to downstream order along Cashmere Stream).
- Urban and rural land use both cause sediment input into the waterways, but are variable between tributaries and events making it impossible to make any definitive conclusion about land use effects.
- The effect of the Cashmere Stream sediment input to the Heathcote River/Ōpāwaho is variable between events. In some cases there was higher sediment input from the Heathcote River/Ōpāwaho upstream of the Cashmere Stream confluence and in other events it was the opposite scenario.
- Predominant sediment type is clay-silt (very fine) so the impact from this sediment extends a long way downstream as this type of sediment takes a long time to settle out of the water.
- Fine sediment is difficult to remove in settlement ponds so creates a management problem.
The locations within the Cashmere Stream catchment of the worst (orange) tributaries for sediment overall.
Sources of sediment input into Cashmere Stream (Report January 2010) [PDF 12MB]
These investigations have helped identified types of contaminants in these waterways, their concentrations and where they are entering the urban waterway system.
These detailed studies will assist Environment Canterbury, in partnership with the Christchurch City Council and other key organisations, to work to reduce the level of contaminants in our waterways. This will be achieved by working collaboratively with all businesses and residents in the catchment areas.
City Wide Monitoring
Christchurch City Council is undertaking monitoring into the effectiveness of new stormwater detention facilities and has 24 monitoring sites on the waterways catchments network to gauge the health of our streams and rivers.
Find out more about CREAS (Christchurch River Environment Assessment System) »
Okeover Stream
The HydroEco Research Team from the University of Canterbury carry out real time water quality and flow monitoring on the Okeover Stream.