Water quality in the Orari River catchment - NZ Landcare Trust Water Quality... · Orari River...
Transcript of Water quality in the Orari River catchment - NZ Landcare Trust Water Quality... · Orari River...
Topics
• Life supporting capacity?
• Other catchment values
• Ecosystem health
• Periphyton and macrophytes
• Abiotic factors (nutrients, sediment, temp, DO)
• Contact recreation
• Summary
Life supporting capacity
• Direct measures
– Fish community
– Invertebrate community
– Algae and macrophyte community
Life supporting capacity
Toxicants
Water clarity
Habitat
Temperature
Useable area/ flow
Periphyton/ macrophyte
coverage
Dissolved
oxygen
pH
Sedimentation/ substrate
Connectivity
Spawning
substrate
• Indirect measures
Other values…
• Recreation / aesthetic • E. coli
• Potentially toxic algae
• Mahinga kai • E. coli
• Potentially toxic algae
• Toxicants
• Availability
• Irrigation and potable supplies
Ecosystem health
• QMCI?
Ecosystem health
QM
CI
Ora
ri River
- Lo
chab
er
Oha
pi C
reek
Nor
th b
ranc
h
Rho
des Stre
am- P
arke
Rd
Pet
ries Dra
in-C
al R
d
Oha
pi C
reek
- Guild rd
Oha
pi C
reek
Sou
th B
ranc
h
Oha
pi C
reek
-u/s O
rari
Coo
pers
Cre
ek-S
H72
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Ecosystem health
Site Location Source of Flow
Trend p Value
% change per annum
Orari River Lochaber Road Hill_upland 0.569 NA
Ohapi Creek North branch
Guild Road SF_plains 0.79 NA
Rhodes Stream
Parke Rd and Donahue Rd SF_plains 0.044 2.404
Petries Drain Canal Road SF_plains 0.277 NA
Rhodes Stream
Rolleston Road SF_plains 0.091 NA
Ohapi Creek Guild Rd SF_plains 0.704 NA
Ohapi Creek South Branch
Guild Rd SF_plains 0.495 NA
Ohapi Creek upstream Orari River
Confluence SF_plains 0.046 -2.414
Orakipaoa Creek
Milford Lagoon Rd SF_plains 0.171 NA
Coopers Creek
SH72 SF_plains 0.283 NA
Algae and macrophytes
• Ecosystem and aesthetic/
recreational impacts at high levels of
cover
• Growth regulated by nutrient
availability, flow, light, temperature
etc
• Ecosystem and aesthetic/
recreational and land drainage
impacts at high levels of cover
• Growth regulated by sediment
cover, nutrient availability, flow, light,
temperature etc
Algae • Upper Orari River (Gorge)
• Didymo, but no filamentous algae or cyanobacteria
issues
• Lower Orari River
• NPS Band C for Chl A
• Seldom exceeds filamentous algae threshold
• Petries Creek
• Infrequent breaches of filamentous algae threshold
• Rhodes Creek
• No major algal issues until lower down and below old
lagoon
• Coopers Creek – SH72
• Infrequent Cyanobacteria blooms
• Ohapi Creek
• No issues in lower reaches
Macrophytes
• An issue in all spring fed streams we
monitor in the catchment, except in
upper Coopers Creek.
• Not an issue in the Orari River
Toxicity Nitrate Ammonia
2014-15 2014-15
Ohapi Creek -
Lower A A
Orari Gorge A A
Orari River - Parke
Rd B A
Rhodes Stream D A
Temperature, dissolved oxygen
and pH • Temperature
• Affects metabolism, and can cause behavioural changes
• Related to ambient temperature, source of flow, flow
volume and shading
• pH
• Influenced by catchment geology, dissolved oxygen, and
therefore flow source and eutrophication
• Dissolved Oxygen
• A requirement for aquatic life
• Influenced by temperature, water velocity/depth and
primary productivity
Temperature, dissolved oxygen
and pH • Temperature <19oC
• Lower Orari River??
• pH 6.5 – 8.5 • No obvious issues
• Dissolved Oxygen >90% • Spring fed sites, except
upper Coopers Creek
But……….
Long term site trends
Site
Total
suspended
solids
Ammonia
nitrogen
Nitrate and
nitrite nitrogen
Dissolved
reactive
phosphorus
E coli
P RSKSE P RSKSE P RSKSE P RSKSE P RSKSE
North Branch Ohapi Creek
Guild Rd 0.000 -8.9 0.000 -7.6 0.059 2.4 0.026 -2.9 0.908 0.0
Ohapi Creek Above Orari
Confluence 0.002 -4.9 0.000 -7.2 0.233 1.1 0.040 -3.1 0.823 1.1
Ohapi Creek Guild Rd 0.000 -5.0 0.000 -7.3 0.053 3.0 0.489 -0.8 0.105 -4.2
South Branch Ohapi
Creek Guild Rd 0.231 -1.9 0.000 -6.1 0.406 0.8 0.181 -2.5 0.436 2.3
• Reduction seen in TSS and
ammonium nitrogen in Ohapi
Creek catchment
10 year trends
Site
Total suspended
solids
Ammonia
nitrogen
Nitrate and
nitrite nitrogen
Dissolved
reactive
phosphorus
E coli
P RSKSE P RSKSE P RSKSE P RSKSE P RSKSE
Coopers Creek SH72 Bridge 0.617 -1.9 0.004 -9.9 0.215 4.9 0.479 -1.6 0.320 6.6
North Branch Ohapi Creek
Guild Rd 0.263 -2.8 0.077 -5.0 0.165 4.4 0.445 -2.4 0.324 5.2
Ohapi Creek Above Orari
Confluence 0.244 4.2 0.061 -6.2 0.574 1.3 0.052 -5.0 0.031 8.5
Ohapi Creek Guild Rd 0.323 -2.4 0.116 -6.4 0.020 7.0 0.687 -1.1 0.126 5.0
Orari River Mouth Reserve 0.302 -3.5 0.015 -5.4 0.057 2.1 0.163 -2.4 0.022 9.9
Orari River Parke Rd 0.929 0.4 0.000 -10.3 0.559 2.1 0.649 0.0 0.139 4.8
Petries Drain Canal Road 0.637 -14.6 0.033 -17.9 0.374 -0.8 0.156 -22.3 0.017 4.3
Rhodes Stream Parke Road 0.589 -1.5 0.000 -14.6 0.299 1.3 0.011 -12.4 0.502 -3.1
South Branch Ohapi Creek
Guild Rd 0.685 -0.8 0.590 1.0 0.028 -7.9 0.066 7.0
Current state –physico chemical
analysis
Median
TSS Median
NNN Median
DRP Median
E.coli Median
E.coli
mg/L mg/L mg/L MPN/100m
L MPN/100m
L
Coopers Creek SH72 Bridge 1.5 0.900 0.003 299 1812
North Branch Ohapi Creek Guild Rd 5.3 0.665 0.007 270 1987
Ohapi Creek Above Orari Confluence 6.1 0.795 0.018 622 2420
Ohapi Creek Guild Rd 7.2 0.765 0.032 534 2410
Orari River Mouth Reserve 2.0 9.350 0.008 291 2410
Orari River Parke Rd 1.5 1.365 0.003 40 719
Petries Drain Canal Road 1.4 5.350 0.003 175 2400
Rhodes Stream Parke Road 2.1 10.650 0.002 113 2402
South Branch Ohapi Creek Guild Rd 5.6 0.975 0.011 564 2420
Periphyton limits – 40 day accrual (actually 38.3)
DIN – 0.034mg/L, DRP – 0.0028mg/L
Contact recreation
Based on E. coli results from the
lower Orari River, it is likely this
site would be graded Poor, or
Very Poor (NPS C band)
Other sites are generally not
suitable for contact recreation
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Contact recreation
• Toxic cyanobacteria (toxin, taste)
• Regular blooms in lower Orari River during
the summer
Conclusions
• Spring fed systems most impacted, by
sediment, macrophytes, and nutrients
• Nitrogen elevated in lower Orari River,
and likely to be contributing to
periphyton (incl. cyanobacteria) blooms
in addition to other factors