2024 Quarterly Summaries
August 2024
Water quality was Fair. Nitrogen parameters and suspended sediment were elevated at some sites.
E. coli concentrations were very low at all sites (≤ 98), falling well within recommending health levels for swimming (540). Nitrate concentrations were low at 46-Waiteti stream-Upper (0.36 mg/L) but elevated at the other three sites, where concentrations were above regional, PC1 targets (0.525 mg/L), however, all sites fell well below ecological toxicity levels (2.4 mg/L). Nitrates were lowest at 46-Waiteti Stream-Upper (0.36 mg/L) and highest at 5-Mangawhauwhi stream (1.01 mg/L). Ammonia concentrations were low at all sites (≤ 0.02 mg/L) but exceeded PC1 targets (0.005 mg/L) at three out of four sites. Dissolved inorganic nitrogen (DIN) concentrations were low at 46-Waiteti Stream-Upper (0.37 mg/L), slightly elevated at 4-Mangaokewa stream and 6-Waiteti stream-viaduct (≥ 0.71 mg/L) and elevated at 5-Mangawhauwhi stream (1.02 mg/L). DIN concentrations greater than 0.5 mg/L can cause ecological impacts like excessive growth of algae and aquatic plants, and loss of sensitive species. Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.01 mg/L). Water clarity was excellent at 5-Mangawhauwhi Stream (1.9 m), good at 4-Mangaokewa stream (1.64 m) and poor in the two Waiteti stream sites, relative to the national bottom line (1.34 m).
Sample Collection Day: 13 August 2024
May 2024
Overall water quality was Fair. Nitrogen parameters and suspended sediment were elevated at some sites.
E. coli concentrations were low at all sites (≤ 190), falling within recommending health levels for swimming (540). Nitrate concentrations were low at two sites (≤ 0.41) and elevated at 4-Mangaokewa stream and 5-Mangawhauwhi stream, where they were above regional PC1 targets (0.525 mg/L). All sites fell well below ecological toxicity levels (2.4 mg/L). Nitrates were lowest at 46-Waiteti Stream-Upper (0.15 mg/L) and highest at 4-Mangaokewa stream (0.83 mg/L). Ammonia concentrations were low at two sites (<0.005 mg/L) but exceeded PC1 targets (0.005 mg/L) at the two Waiteti stream sites. Dissolved inorganic nitrogen concentrations were low at the two Waiteti stream sites (≤0.41 mg/L) and slightly elevated at the other two sites, potentially impacting ecological health by promoting excessive growth of algae, aquatic weeds and impacting sensitive aquatic life. Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.007 mg/L). Water clarity was excellent at 5-Mangawhauwhi Stream (3.13 m) and good at the two Waiteti stream sites. Water clarity was poor at 4-Mangaokewa stream (1.14 m), relative to the national bottom line (1.34 m).
Collection date: 14th May 2024 (excl. Site 4 - Mangaokewa stream sampled 20th June 2024)
February 2024
Overall water quality was Fair. E. coli, Dissolved Inorganic Nitrogen and suspended sediment were elevated at some sites.
E. coli concentrations were low at three sites (≤180) but elevated at Mangawhauwhi stream (600), above recommending health levels for swimming (540). Nitrate concentrations were low at all sites, falling below regional PC1 targets (0.525 mg/L) and well below levels where ecological toxicity impacts can occur (2.4 mg/L). Nitrates were lowest at 46-Waiteti Stream-Upper (0.07 mg/L) and highest at 6-Waiteti Stream-Viaduct (0.45 mg/L). Ammonia concentrations were low at 4-Mangaokewa Stream (viaduct) and 46-Waiteti stream (< 0.005 mg/L) but exceeded PC1 targets (0.005 mg/L) at 5-Mangawhauwhi stream and 6-Waiteti stream (≥ 0.006 mg/L). Dissolved inorganic nitrogen concentrations were low at all sites (≤ 0.46 mg/L). Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.01 mg/L). Water clarity was excellent at 4-Mangaokewa Stream (2.39 m) and 6-Waiteti stream (2.78 m) but was poor at 5-Mangawhauwhi stream (1.33 m) and 46-Waiteti stream (1.17 m), relative to the national bottom line (1.34 m).
Collection date: 22nd & 28th February 2024
Water Quality Summary 2023
Water samples were collected from 7 stream and river sites across the Upper Mangaokewa catchment. Monitoring sites were located on Mangaokewa stream, Waiteti stream and the Mangauwhauwhi stream. The below water quality dial summarises 29 individual samples collected across 7 monitoring sites, between January 2023 and December 2023.
Water clarity was poor, indicated elevated levels of suspended sediment, which impacts aquatic life. E. coli and nitrogen were slightly elevated. Elevated Slightly E. coli can is a potential risk to human health when swimming and elevated nitrogen can impact aquatic life and river health by promoting excessive growth of algae, bacteria and aquatic weeds and decreasing dissolved oxygen levels in the water. Dissolved reactive phosphorus (DRP) was low, which supports river health. Water clarity did not meet national water quality standards, while nitrate and ammonia concentrations did not meet regional (Plan Change 1) short-term targets. Dissolved reactive phosphorus, nitrate and ammonia toxicity and E. coli did meet national standards.
Arrows indicate an increase or decrease in values compared to the baseline. The baseline was calculated from 5 years of data collected by Waikato Regional Council at Lawrence St Bridge in Te Kūiti, between 2015 and 2019. An increase in water clarity is positive for river health, while an increase in all other attributes may impair river health.
Aquatic Biodiversity Summary
Biodiversity monitoring includes eDNA, collected by KCRC, and traditional biodiversity monitoring techniques (netting of freshwater invertebrates and netting and electrofishing of freshwater fish), by Waikato Regional Council (WRC). eDNA sampling has been done by KCRC, in autumn and winter in 2021, 2022 and 2023. WRC monitors most sites every 1 to 2 years, between November and March. If more than one results is available for any single monitoring location the results for that site are averaged across years.
Upper Mangaokewa
The upper Mangaokewa has high ecological value but shows some signs of stress.
The eDNA site had a high fish score but a low MCI score.
Across the catchment MCI scores were good at 3 out of 5 sites.
Rare native species of fish were detected, including lamprey, longfin eel and torrentfish.
No whitebait species were detected.
Three species of introduced fish detected, mosquito fish, brown trout and rainbow trout.
There is a clear migration pathway for native fish from the sea due to no dams being constructed on the Waipa River or Waikato River, downstream of lake Karapiro.
2023 Quarterly Summaries
November 2023
Water quality was variable between sites, ranging from good to poor due to elevated E. coli, nitrogen and suspended sediment. E. coli concentrations were low at two sites (140) and elevated at two sites (≥ 330). Nitrate concentrations were below toxicity levels at all sites but exceeded regional PC1 targets (0.525 mg/L) at 2 out of 4 sites (between 0.56 – 0.70 mg/L). Nitrate concentrations were lowest at 46-Waiteti Stream-Upper (0.09 mg/L) and highest at 5-Mangawhauwhi Stream (0.70 mg/L). Ammonia concentrations were low at 4-Mangaokewa Stream (viaduct) and exceeded PC1 targets (0.005 mg/L) at 3 out of 4 sites (≥ 0.006 mg/L). Two out of four sites had a dissolved inorganic nitrogen concentration exceeding 0.5 mg/L, potentially impacting river health. Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.009 mg/L). Water clarity was excellent at 4-Mangaokewa Stream (2.25 m) and poor at all other sites (between 1.08 m - 1.24 m), relative to the national bottom line (1.34 m).
Collection date: 14 November 2023
September 2023
Overall, water quality was poor at most sites except for site 46-Waiteti stream-Upper, which had good water quality. Poor water quality was associated with elevated concentrations of E. coli, nitrogen and suspended sediment. E. coli concentrations were very low at 46-Waiteti Stream-Upper (52) and were elevated at all other sites (≥ 280). Nitrate concentrations were below toxicity levels at all sites but exceeded regional PC1 targets (0.525 mg/L) at 3 out of 4 sites (between 0.54 – 0.87 mg/L). Nitrate concentrations were lowest at 46- Waiteti Stream-Upper (0.17 mg/L) and highest at 5-Mangawhauwhi Stream (0.87 mg/L). Ammonia concentrations exceeded PC1 targets (0.005 mg/L) at all sites (between 0.009 – 0.03 mg/L). Ammonia concentrations were lowest at 4-Mangaokewa stream-viaduct and 46-Waiteti stream-upper and highest at 6- Waiteti Stream-viaduct (0.03 mg/L). Three out of four sites had a dissolved inorganic nitrogen concentration exceeding 0.5 mg/L, potentially impacting the health of the river. Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.008 mg/L). Water clarity was poor at all sites (between 0.69 m - 1.47 m), relative to the national bottom line (1.34 m).
Collection date: 12 September 2023
May 2023
E. coli concentrations were low at five sites (≤ 240) and elevated at 6-Waiteti Stream-viaduct (470). Nitrate concentrations were below toxicity levels at all sites but exceeded regional PC1 targets (0.525 mg/L) at 4 out of 6 sites (between 0.53 – 0.93 mg/L). Nitrate concentrations were lowest at 46-Waiteti Stream Upper (0.25 mg/L) and highest at 5-Mangawhauwhi Stream (0.93 mg/L). Ammonia concentrations were exceptionally low at 3 out of 6 sites (≤ 0.005 mg/L) and exceeded PC1 targets (0.005 mg/L) at the other 3 sites being highest at 6-Waiteti Stream-viaduct (0.05 mg/L). Four out of six sites had a dissolved inorganic nitrogen concentration exceeding 0.5 mg/L, potentially impacting the health of the river. Dissolved reactive phosphorus concentrations were low at 3 sites (≤ 0.008 mg/L) and elevated at 3 sites being highest at 4-Mangaokewa Stream (viaduct) and 45-Mangaokewa Stream (0.013 mg/L). Water clarity was poor at all six sites (between 0.56 m - 1.20 m), relative to the national bottom line (1.34 m).
Collection date 8 May 2023.
February 2023
Water Quality Summary 2022
The water quality dial for Upper Mangaokewa combines data collected at 7 monitoring sites between January – December 2022, representing 30 individual samples. Dissolved reactive phosphorus (DRP) was low. E. coli was elevated, while water clarity was low indicating high sediment loading. Nitrate was above the Waikato PC1 target value (0.525 mg/L). Arrows indicate an increase or decrease in values compared to the sub-catchment baseline (2015 – 2020). An increase in water clarity is positive for river health while an increase in all other attributes may impair river health.
