Continuous Water Quality
Monitoring
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Advantages
Needed in rapidly changing systems
Provides better understanding of interaction between constituents
Provides better understanding of transport processes
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Disadvantages
Equipment costs are greater
Operation and maintenance costs are greater
Vulnerable to damage and/or loss

Relations Between Parameters
DO and pH
 DO and pH track together
 Diurnal Pattern
 Why?

Relations Between Parameters
DO and Temperature
 Supersaturated
DO
 DO crash in
June
 Variation in
DO changes seasonally

Relations Between Parameters
Turbidity –vs- Discharge

Discrete vs Continuous
Monitoring

Other Surrogate Possibilities
Continuous Parameter(s)
Specific Conductance
Turbidity
Turbidity + Temperature
Surrogate Constituent
TDS, Total Nitrogen
Suspended Sediment, Total
Phosphorous
Bacteria
 Relations are developed using discrete samples and linear regression
 Regression model used to synthesize continuous record of target parameters that are difficult to monitor.
 Parameter -vs- surrogate relations are not universal but site specific

Applications
 Continuous monitoring the constituent or its surrogate to aid in identifying occurrence and duration of waterquality parameters that exceed regulatory limits.

Relation between SC and TN
1,8
0,2
0
0
-0,2
-0,4
1,6
1,4
1,2
1
Proposed Regulatory Limit = 1.0 mg/L
0,8
0,6
Difficult to monitor
0,4
100 200 300
Easy to monitor
SC (uS/cm) ln(TN)
Линейная (ln(TN)) y = 0,0041x - 0,6367
R² = 0,902
400 500 600

Applications (cont)
 Identify and optimize periods for sample collection
 Quantify constituent loads
(volume/time)
 Familiarity with the site and data will lead to a better understanding of physical processes and interactions between constituents