Transcript Application of the Saskatchewan Water Quality Index

Turtle Lake
Water Quality Index
Turtle Lake Watershed Inc.
June 13, 2005
Water Quality Monitoring
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Gathers and collects
data
Provides information
on current conditions
Can show trends in
water quality over time
Provides information
on which to make
decisions
Water Quality Monitoring
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Monitoring programs can be
established for a variety of different
reasons
The parameters monitored can tell
us different things about the water
quality
Parameters can be related to one
another
Each piece of information can be
used to provide an overall
assessment of the water quality
Water Quality Data
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Individual parameters are
compared to some form of
standard/objective
(Saskatchewan Surface
Water Quality Objectives)
Usually based on intended
use of the water
(protection of aquatic life,
irrigation, recreation,
livestock watering)
Water Quality Data
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Parameters that are
within the Surface
Water Quality
Objectives would be
considered suitable for
a particular intended
use.
Monitoring data
Dissolved Oxygen (DO)
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All Aquatic organisms require oxygen
to live
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Fish, invertebrates, plants, and aerobic
bacteria
Objectives set DO levels at 5 mg/L
for the protection of fish and aquatic
life
Levels below 3 mg/L can be stressful
for most aquatic organisms;
Levels below 1 mg/L are considered
to be anoxic (no oxygen present)
Total Phosphorous
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Is an essential nutrient for plant
and animal growth
Occurs naturally in the
environment
Enters water bodies as a result of
surface run-off, soil erosion, decay
of organic matter, and waste
High phosphorous levels can
stimulate algal and weed growth
(TP greater than 0.1 mg/L)
Nitrogen
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Occurs in several forms in water
–
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It is an important plant nutrient
Ammonia nitrogen is used as an indicator of the
quality of the water for aquatic life
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Ammonia, nitrate, nitrite, and organically bound
High ammonia concentrations can be toxic to fish
Nitrate levels are typically less that 1 mg/L in
healthy surface water systems
Total Dissolved Solids (TDS)
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Is a measure of the amount of dissolved material in water
– Bicarbonate, sulphate, chloride, calcium, magnesium,
sodium, and potassium
Concentration of TDS depends on:
– The amount of precipitation a water body receives
– The type of solid and rock the water passes over
– Human activities
TDS levels for irrigation should not exceed 700 mg/L
Turtle Lake TDS values range between 576-750 mg/L
Turbidity
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Indicates the amount of
suspended material in water
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Soil particles, algae, or other
microscopic organisms
High turbidity reduces light
penetration, productivity and
habitat quality
Suspended sediment can carry
nutrients, metals, and
pesticides
Heavy Metals
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Can be toxic to the aquatic environment at
elevated levels
Some metals can bio-accumulate, e.g. mercury
Occurs naturally in the environment
Enters water bodies as a result of surface run-off,
soil erosion, or improper waste disposal
Can restrict water use
Algal Blooms
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Common in nutrient-rich surface
waters
Main types include:
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Green algae and diatoms = nuisance
organisms
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Green algae, diatoms, and blue-green
algae (cyanobacteria)
Plug irrigation equipment, affect
recreation, treatment plant operations,
and can produce taste and odour
compounds
Blue-green algae = toxic organisms
–
Produce neuro- and hepato-toxins
Fecal Coliforms
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Used as an indicator of the sanitary quality of
water
Found in the intestinal tract of human and other
warm blooded animals
A high fecal coliform count indicates water
contamination
For recreational use of a water body, levels should
not exceed mean density of 200 organisms per 100
mL, must be absent in drinking water
Water Quality Index
Water Quality Index
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The WQI is a
simple tool that can
be used to
summarize and
report on complex
water quality
monitoring data
What is the Water Quality Index?
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It is a mathematically calculation that
combines a number of water quality factors
and then ranks the water quality in a simple
and easily understood way
It can be used to report on the overall and
on-going condition of a water body in a way
that can be used by technical and non
technical people
Development of the Water
Quality Index
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The Canadian Water Quality Index was
developed by a Federal/Provincial
Taskforce for the Canadian Council of
Ministers of the Environment
It was based on an index developed by
British Columbia - Ministry Environment,
Land and Parks
CWQI
The Water Quality Index is based on a
combination of three factors:
 the number of variables whose objectives
are not met (scope)
 The frequency with which the objectives are
not met (frequency) and
 The amount by which the objective is not
met (amplitude)
Water Quality Index
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Combining all water quality parameters the
water quality index produces a number
between 0 and 100, where 0 represents the
“worst” water quality and 100 represents
the “best” water quality.
CWQI
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Excellent: (CWQI Value 95-100)
– water quality is protected with a virtual absence
of threat or impairment; conditions very close to
natural or pristine levels.
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Good: (CWQI Value 80-94)
– water quality is protected with only a minor
degree of threat or impairment; conditions rarely
depart from natural or desirable levels.
CWQI
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Fair: (CWQI Value 65-79)
– water quality is usually protected but
occasionally threatened or impaired; conditions
sometimes depart from natural or desirable levels.
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Marginal: (CWQI Value 45-64)
– water quality is frequently threatened or
impaired; conditions often depart from natural or
desirable levels.
CWQI
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Poor: (CWQI Value 0-44) – water quality is
usually threatened or impaired; conditions usually
depart from natural or desirable levels.
Saskatchewan Water Quality Index
for use in Watershed Protection
Parameters used in the SWA Water Quality Index
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Total Dissolved Solids
Sulphate
Chloride
Sodium
Nitrate/nitrite
Ammonia
Total Phosphorous
Chromium
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Mercury
Aluminum
Arsenic
pH
Dissolved oxygen
Chlorophyll a
MCPA
2, 4-D
Fecal coliforms
Turtle Lake
Water Quality Index
100
90
90.1
80
70
60
CWQI
Score
50
40
30
20
na
na
10
0
2001
2003
Year
2004
Water Quality Index
Turtle Lake
Turtle Lake water quality rated as Good
(WQI value 90.1)
– water quality is protected with only a minor
degree of threat or impairment; conditions
rarely depart from natural or desirable
levels.
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Turtle Lake
Summary
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Water Quality Index rating was good
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Parameters that exceeded the WQI objectives the
most were pH and TDS
In 2004:
 pH 8.83 – 9.38
 TDS 576-583, 750
WQI Summary
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Provides a simple ranking system to
evaluate water quality - although some
interpretation is still required.
Can be used to assess overall watershed
health and assess changes in water quality
over time
Questions?