1. CE5504 Surface Water Quality Modeling
General Lecture 2. Model Development
CE5504 – Surface Water Quality Modeling

2. Secchi disk and chlorophyll
Empirical Models
Secchi disk and chlorophyll
(Chapra 1997, Figure 29.6)
CE5504 – Surface Water Quality Modeling

3. Empirical Models Vollenwieder plot (Chapra 1997, Figure 29.1)
CE5504 – Surface Water Quality Modeling

4. Linked Empirical-Mechanistic Models
(Chapra 1997, Figure 29.4)
CE5504 – Surface Water Quality Modeling

5. Mechanistic Mass Balance Models
(Chapra 1997, Figure 1.5)
CE5504 – Surface Water Quality Modeling

6. Temporal Resolution (Chapra 1997, Figure 18.8)
CE5504 – Surface Water Quality Modeling

7. Spatial Resolution (Chapra 1997, Figure 16.1)
CE5504 – Surface Water Quality Modeling

8. Time and Space Scale of Water Quality Problems
(Chapra 1997, Figure 18.9)
CE5504 – Surface Water Quality Modeling

9. Kinetic Resolution Soluble Reactive Phosphorus Total Phosphorus
Dissolved
Organic
Phosphorus
Available
Particulate
Phosphorus
Refractory
Particulate
Phosphorus
CE5504 – Surface Water Quality Modeling

10. The Guiding Principle
Things should be made as simple as possible -- but no simpler.
Albert Einstein
image source:

11. Defensible, Credible, Cost-Effective
unlimited cost
cost
cost + $
desired reliability
Model Complexity
Model Reliability

12. Striking a Balance
Model Complexity
Screening  Management  Research

13. Modeling: Historical Development
(Streeter-Phelps)
Problems: untreated and primary effluent
Pollutants: BOD
Systems: streams and estuaries (1D)
Kinetics: linear, feed forward
Solutions: analytical
(Chapra 1997)
CE5504 – Surface Water Quality Modeling

14. Modeling: Historical Development
(Computerization)
Problems: primary and secondary effluent
Pollutants: BOD
Systems: streams and estuaries (1D/2D)
Kinetics: linear, feed forward
Solutions: analytical and numerical
(Chapra 1997)
CE5504 – Surface Water Quality Modeling

15. Modeling: Historical Development
(Biology)
Problems: eutrophication
Pollutants: nutrients
Systems: streams, lakes and estuaries (1D/2D/3D)
Kinetics: nonlinear, feedback
Solutions: numerical
(Chapra 1997)
CE5504 – Surface Water Quality Modeling

16. Modeling: Historical Development
(Toxics)
Problems: toxics
Pollutants: organics, metals
Systems: sediment-water interactions
food chain interations, streams, lakes and estuaries
Kinetics: linear, feed forward
Solutions: analytical
(Chapra 1997)
CE5504 – Surface Water Quality Modeling

17. Modeling: Historical Development
present (Ecosytems)
Problems: ecosystem change, climate, invasives
Pollutants: natural components – carbon, nutrients, organisms
Systems: primary production, food web interactions
Kinetics: nonlinear, feedback
Solutions: numerical
Benthic Invertebrates
Phytoplankton
Whitefish
(Chapra 1997)
CE5504 – Surface Water Quality Modeling