2024 Quarterly Results
August 2024
Water quality was Fair. Dissolved inorganic nitrogen was slightly elevated at two sites and water clarity was low at all sites.
E. coli concentrations were low at all sites (≤ 240), falling well within the recommended health limits for swimming (540). Nitrate concentrations were low at all sites, falling well below ecological toxicity levels (2.4 mg/L). Nitrate concentrations were lowest at 42-Kiritehere Stream (< 0.12 mg/L) and highest at 39-Mangaohuinga stream (0.65 mg/L) and 40-Wairoa stream (0.66 mg/L). Ammonia concentrations were low at all sites (≤ 0.01 mg/L). Dissolved inorganic nitrogen (DIN) was slightly elevated at two sites, 39-Mangaohuinga stream and 40-Wairoa stream. 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 (≤ 0.007). Water clarity was poor at all sites (≤ 0.83 m), relative to the national bottom line (1.34 m).
Sample Collection Day: 22nd August 2024
May 2024
Water quality was Good, except for dissolved reactive phosphorus and water clarity, which were impacted across several sites.
E. coli concentrations were very low at all sites (≤ 130), falling well within the recommended health limits for swimming (540). Nitrate concentrations were low at all sites, falling well below ecological toxicity levels (2.4 mg/L). Nitrate concentrations were lowest at 42-Kiritehere Stream (< 0.03 mg/L) and highest at 39-Mangaohuinga stream (0.43 mg/L). Ammonia concentrations were low at all sites (≤ 0.02 mg/L). Dissolved inorganic nitrogen was low at all sites. Dissolved reactive phosphorus concentrations were low at 3 sites (≤ 0.007) and slightly elevated at 39-Mangaohuinga stream (0.011 mg/L). Water clarity was excellent at 39-Mangaohuinga stream and 42-Kiritehere stream (≥ 1.79 m) but was poor at 40-Wairoa stream and 41-Puaroa stream (≤ 1.24 m), relative to the national bottom line (1.34 m).
Collection date: 13th May 2024
February 2024
Water quality was Excellent at 39-Mangaohuinga Stream and Good at all other sites, except for water clarity.
E. coli concentrations were low at all sites (≤ 220), falling within the recommended health limits for swimming (540). Nitrate concentrations were low at all sites, falling well below levels where ecological toxicity impacts can occur (2.4 mg/L). Nitrates were lowest at 42-Kiritehere Stream (< 0.01 mg/L) and highest at 40-Wairoa Stream (0.24 mg/L). Ammonia concentrations were exceptionally low at all 4 sites (≤ 0.005 mg/L). Dissolved inorganic nitrogen was low at all sites, falling below concentrations that can cause ecological impacts (0.5 mg/L), like problematic growth of algae and aquatic plants, and the loss of sensitive aquatic species. Dissolved reactive phosphorus concentrations were low at all sites (≤ 0.007). Water clarity was excellent at 39-Mangaohuinga Stream (1.84 m), slightly reduced at 41-Puaroa stream and 42-Kiritehere stream (≤ 1.52 m) and poor at 40-Wairoa stream (1.08 m), relative to the national bottom line (1.34 m).
Collection date: 14th February 2024
Summary 2023
Water samples were collected from 6 stream or river sites across the Marokopa catchment in 2023. The sites are located on Mangaohuinga stream, Wairoa stream, Puaroa stream, Kiritehere stream (all sampled quarterly), and Tawarau river and Marokopa river (both sampled monthly).
The below water quality dial for Marokopa represents 38 individual samples and summaries the monitoring results from these 6 locations collected between January 2023 – December 2023.
E. coli and suspended sediment were elevated and did not meet human health (for swimming) or ecological health standards. Dissolved reactive phosphorus was also slightly elevated, which may impact ecological health. Nitrogen was low and is unlikely to impact ecosystem health.
Arrows indicate an increase or decrease in values compared to the baseline for Marokopa River. No arrows indicate where there’s no deviation from baseline values. The baseline was calculated from 5 years of data collected at the Tawarau and Marokopa river monitoring sites, between 2016 – 2020. An increase in water clarity is positive for river health, while an increase in all other attributes may impair river health.
Marokopa Dial 2023.
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.
Marokopa river had good ecological health indicators, however, there is low fish diversity in the mid to upper catchment, above the waterfall. The fish community above the waterfall is dominated by eels only.
Marokopa waterfall is 35 meters high, it is a cascading water so although it is considered a significant barrier to fish migration some native kōkopu species, koaro and eels would likely be able to traverse it.
The fish community was diverse in Kiritehere stream, suggesting the same would be true in Marokopa river, downstream of the waterfall.
Seven species of threatened fish were detected via eDNA in Kiritehere stream, including lamprey, Īnanga, Giant kōkopu, Shortfin kōkopu, Longfin eel, Redfin bully and Torrentfish.
Only 1 species of introduced fish was detected across the whole catchment, brown trout.
Invertebrate MCI was good at all monitoring sites, suggesting there is good habitat at these locations.
The number of insect species at Kiritehere stream is moderate at 25.
2023 Quarterly Results
November 2023
Water quality was excellent at 39-Mangaohuinga Stream and good at all other sites, except for water clarity which was low at sites 40, 41 & 42.
E. coli concentrations were exceptionally low at all 4 sites (≤ 110). Nitrate concentrations were well below toxicity levels at all sites being lowest at 42-Kiritehere Stream (< 0.01 mg/L) and highest at 40-Wairoa Stream (0.25 mg/L). Ammonia concentrations were exceptionally low at all 4 sites (< 0.005 mg/L). The combined concentration of Nitrate + Ammonia was below 0.5 mg/L at all sites. Ecological impacts, including problematic growth of algae and/or aquatic plants and loss of sensitive aquatic species are likely when the combined concentration of nitrate and ammonia regularly exceed 0.5 mg/L. Dissolved reactive phosphorus concentrations were low at all 4 sites (≤ 0.009). Water clarity was excellent at 39-Mangaohuinga Stream and poor at all sites (≤ 1.46 m), relative to the national bottom line (1.34 m).
Collection date: 10 November 2023
August 2023
Overall water quality was good except for water clarity which was low at all 4 sites. E. coli concentrations were exceptionally low at all 4 sites (≤ 54). Nitrate concentrations were below toxicity levels at all sites being lowest at 42-Kiritehere Stream (0.07 mg/L) and highest at 39-Mangaohuinga Stream (0.70 mg/L). Ammonia concentrations were low at 3 out of 4 sites (≤ 0.007 mg/L) and higher at 40-Wairoa Stream (0.02 mg/L). Sites 39 and 40 (Mangaohuinga stream and Wairoa stream) both had a combined concentration of Nitrate + Ammonia equivalent to 0.70 mg/L. Ecological impacts, including problematic growth of algae and/or aquatic plants and loss of sensitive aquatic species are likely when the combined concentration of nitrate and ammonia regularly exceed 0.5 mg/L. Dissolved reactive phosphorus concentrations were low at all 4 sites (≤ 0.01). Water clarity was poor at all sites (≤ 0.95 m), relative to the national bottom line (1.34 m).
Collection date: 25 August 2023
May 2023
E. coli concentrations were low at 3 out of 4 sites (≤ 230) and were slightly elevated at 42-Kiritehere Stream (290). Nitrate concentrations were below toxicity levels at all sites being lowest at 42-Kiritehere Stream (0.08 mg/L) and highest at 40-Wairoa Stream (0.69 mg/L). Ammonia concentrations were exceptionally low at 3 out of 4 sites (< 0.005 mg/L) and higher at 40-Wairoa Stream (0.02 mg/L). 40-Wairoa Stream and 39-Mangaohuinga Stream both had a combined concentrations of Nitrate + Ammonia exceeding 0.5 mg/L. Ecological impacts, including problematic growth of algae and/or aquatic plants and loss of sensitive aquatic species are likely when the combined concentration of nitrate and ammonia regularly exceed 0.5 mg/L. Dissolved reactive phosphorus concentrations were low at 3 out of 4 sites (≤ 0.01) and elevated at 39-Mangaohuinga Stream (0.011 mg/L). Water clarity was poor at all sites (≤ 0.77 m), relative to the national bottom line (1.34 m).
Collection date: 18 May 2023
Water Quality Summary 2022
The water quality dial for Marokopa River combines data collected at 6 monitoring sites between January 2022 – February 2023, representing 39 individual samples. Nitrates were low. E. coli and dissolved reactive phosphorus (DRP) were elevated, while water clarity was low indicating sediment loading. Arrows indicate an increase or decrease in values compared to the sub-catchment baseline (2016 – 2020). An increase in water clarity is positive for river health while an increase in all other attributes may impair river health.
