Table 3.8 List of parameters or indicators and reasons for including them in the WQI
Parameters/indicators
of water quality
Include as
part of WQI? Reasoning
Specific conductance
(μS/cm)
Yes
Compared to reference conditions, it indicates dissolved
pollutants and potential upstream watershed
disturbances.
Dissolved oxygen
(%)
Yes
A standard water quality parameter. It indicates oxygen
demand as well as supersaturation (evidence of excessive alga and nutrient enrichment).
pH (s.u.)
Yes
A standard water quality parameter. Values outside of
desired range may indicate a water quality problem.
Water temperature
(
C)
Maybe
If monitoring is conducted in summer then yes; otherwise, no. project dependent (Mtns vs. coast)
Nitrite-nitrate nitrogen (mg/L)
Yes
Compared to reference conditions, it provides evidence
of nutrient enrichment, disturbance, and pollution
sources.
Total Kjeldahl nitrogen (mg/L)
Yes
Same as above.
Ammonia nitrogen
(mg/L)
Yes
Same as above.
Total phosphorus
(mg/L)
Yes
Same as above.
Total suspended residue (mg/L)
No
Turbidity and bank stability metrics below will capture
potential sediment pollution. During baseflow, this
parameter may not adequately reflect the potential for
sediment pollution.
Turbidity (NTU)
Depends
Indicates potential sediment or particulate pollution. If
stream bank stability metric below is included, turbidity
may not need to be included. However, it could provide
evidence of sources if turbidity is present during
baseflow.
Sodium (mg/L)
No
Specific conductance will capture problem levels.
Chloride (mg/L)
No
Same as above.
Metals (Cu, Zn, Pb,
etc.)
No
Typically levels are very low. Uncertainty remains in
interpreting total recoverable vs. dissolved data. Turbidity and other sediment indicators will capture potential problem.
Fecal coliform (cols/
100 mL)
Yes
Indicates potential sewer line leaks, failing septic systems and upstream livestock operations.
Organics
No
Too expensive. Other parameters could be a surrogate
for organic pollutants.
Livestock access
Yes
We know that livestock represent a stressor to both
water quality and the riparian environment.
Light penetration
(shading)
No
Riparian vegetation would capture this parameter.
Bank stability
Yes
This metric captures a source of sediment pollution
during storm flow and may be the sole metric to represent potential sediment pollution during storm flow.
Others are listed below.
(continued)
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H. A. Aziz et al.
Parameters/indicators
of water quality
Include as
part of WQI? Reasoning
Specific conductance
(μS/cm)
Yes
Compared to reference conditions, it indicates dissolved
pollutants and potential upstream watershed
disturbances.
Dissolved oxygen
(%)
Yes
A standard water quality parameter. It indicates oxygen
demand as well as supersaturation (evidence of excessive alga and nutrient enrichment).
pH (s.u.)
Yes
A standard water quality parameter. Values outside of
desired range may indicate a water quality problem.
Water temperature
(
C)
Maybe
If monitoring is conducted in summer then yes; otherwise, no. project dependent (Mtns vs. coast)
Nitrite-nitrate nitrogen (mg/L)
Yes
Compared to reference conditions, it provides evidence
of nutrient enrichment, disturbance, and pollution
sources.
Total Kjeldahl nitrogen (mg/L)
Yes
Same as above.
Ammonia nitrogen
(mg/L)
Yes
Same as above.
Total phosphorus
(mg/L)
Yes
Same as above.
Total suspended residue (mg/L)
No
Turbidity and bank stability metrics below will capture
potential sediment pollution. During baseflow, this
parameter may not adequately reflect the potential for
sediment pollution.
Turbidity (NTU)
Depends
Indicates potential sediment or particulate pollution. If
stream bank stability metric below is included, turbidity
may not need to be included. However, it could provide
evidence of sources if turbidity is present during
baseflow.
Sodium (mg/L)
No
Specific conductance will capture problem levels.
Chloride (mg/L)
No
Same as above.
Metals (Cu, Zn, Pb,
etc.)
No
Typically levels are very low. Uncertainty remains in
interpreting total recoverable vs. dissolved data. Turbidity and other sediment indicators will capture potential problem.
Fecal coliform (cols/
100 mL)
Yes
Indicates potential sewer line leaks, failing septic systems and upstream livestock operations.
Organics
No
Too expensive. Other parameters could be a surrogate
for organic pollutants.
Livestock access
Yes
We know that livestock represent a stressor to both
water quality and the riparian environment.
Light penetration
(shading)
No
Riparian vegetation would capture this parameter.
Bank stability
Yes
This metric captures a source of sediment pollution
during storm flow and may be the sole metric to represent potential sediment pollution during storm flow.
Others are listed below.
(continued)
78
H. A. Aziz et al.