Water quality still murky in SC
The water quality in several South Canterbury rivers has declined according to a new comprehensive New Zealand-wide study of river water quality.
Land, Air, Water Aotearoa (Lawa) released the new river water quality monitoring data for all 16 regions in country yesterday to mark World Rivers Day.
In the Opihi River catchment alone, the Opuha River at Skipton Bridge, the Hae Hae Te Moana River, the Opihi River mouth, and Opuha River were all listed as likely declining in water quality due to E.coli.
In the Pareora River catchment, the river at SH1 is listed as D and not improving, while the river at the Huts is also listed as a D and not improving.
However, the Temuka River and Smithfield Creek, which both had ‘‘D’’ ratings for E.coli were also listed as being ‘‘very likely improving’’. The report also contains data on ‘‘recreational water quality’’ and shows two of three test sites in Caroline Bay, Timaru, are currently ‘‘unsuitable for swimming’’ while ‘‘caution advised’’ for the third.
The ‘‘unsuitable for swimming’’ tags are also consigned to two sites in the Pareora River, two sites in the Waihao River, the Hakataramea River at the SH82 bridge near Kurow, the Opihi River’s three sites, the Temuka River and at Lake Opuha at the Ewarts Corner boat ramp.
The Lawa report notes that the lower reaches of rivers and streams have moderate nutrient enrichment often with high bacterial concentrations in the Opihi River catchment.
‘‘This is most likely a result of the subsequent effects of high land use pressures from such activities as pastoral beef and sheep, dairying and cropping through which these waterways flow,’’ the report says.
The report also notes that in the Pareora catchment, there is low to moderate intensity pastoral grazing of sheep and cattle, and some native and exotic forest.
In the lower reaches land use is moderately intensive pastoral grazing, cropping and dairying’’.
It also says in general ‘‘Canterbury has been experiencing declines in water quality in recent years, with lowland streams having the poorest quality’’. Environment Canterbury chief scientist and Lawa river water quality lead Dr Tim Davie said through improved regional council monitoring networks and science programmes, the sector is learning more about where the pressures are.
‘‘Since 2015, the number of river and stream sites regularly monitored by the regional sector and reported on the Lawa website has increased by more than a third,’’ Davie said.
‘‘This represents significant investment and a commitment to better understanding our freshwater quality and the interventions that can help. Interventions to improve river health include preventing sediment and nutrients entering waterways, upgrading infrastructure, using water sensitive urban design, restoring stream habitats, and ensuring appropriate flows.’’
ECan chairwoman Jenny Hughey said it was important to reflect on the state of all Canterbury rivers and streams, and particularly the iconic braided rivers. ‘‘The Lawa river water quality national picture summary from 2010 to 2019 shows a similar result for Canterbury as for the rest of the country,’’ Hughey said.
‘‘It’s a mixed bag illustrating little change over the last few years. One thing is clear however – the more intensive the land use, the poorer the water quality.’’
Hughey said ECan been addressing the challenge for several years, primarily via the Canterbury Water Management Strategy. ‘‘In rural areas, we have auditable farm environment plans, nutrient limits and stock exclusion rules, all of which are now focused on by the Government’s Essential Freshwater package including the important concept of Te Mana o te Wai (the health of the waterway comes first),’’ she said.