Embed Size (px)
Citation preview
CE4505 – Surface Water Quality Engineering
CE4505 Surface Water Quality Engineering
Modeling Lecture 2. Model Development
Empirical Models
Secchi disk and chlorophyll
(Chapra 1997, Figure 29.6) CE4505 – Surface Water Quality Engineering
Empirical Models
Vollenwieder plot
(Chapra 1997, Figure 29.1) CE4505 – Surface Water Quality Engineering
(Chapra 1997, Figure 29.4)
Linked Empirical-Mechanistic Models
CE4505 – Surface Water Quality Engineering
Mechanistic Mass Balance Models
(Chapra 1997, Figure 1.5)
accumulation loadings transport reactions
in out reactiondm
m m mdt
1 1 1' ( ) ' ( ) nii i i i i i
dCV W Q C Q C E C C E C C V k C
dt
CE4505 – Surface Water Quality Engineering
(Chapra 1997, Figure 18.8)
Temporal Resolution
CE4505 – Surface Water Quality Engineering
Spatial Resolution
(Chapra 1997, Figure 16.1) CE4505 – Surface Water Quality Engineering
Time and Space Scale of Water Quality Problems
(Chapra 1997, Figure 18.9) CE4505 – Surface Water Quality Engineering
Kinetic Resolution
TotalPhosphorus
AvailableParticulate
Phosphorus
RefractoryParticulate
Phosphorus
DissolvedOrganic
Phosphorus
SolubleReactive
Phosphorus
CE4505 – Surface Water Quality Engineering
Things should be made as simple as possible -- but no simpler.
Albert Einstein
image source: www.physik.uni-frankfurt.de/~jr/physpiceinstein.html
The Guiding Principle
CE4505 – Surface Water Quality Engineering
unlimited cost
cost
cost + $
desired reliability
Model Complexity
Mod
el R
elia
bilit
y
Defensible, Credible, Cost-Effective
CE4505 – Surface Water Quality Engineering
Model Complexity
Screening Management Research
Striking a Balance
CE4505 – Surface Water Quality Engineering
1925-1960 (Streeter-Phelps)• Problems: untreated and primary effluent• Pollutants: BOD• Systems: streams and estuaries (1D)• Kinetics: linear, feed forward• Solutions: analytical
Modeling: Historical Development
(Chapra 1997) CE4505 – Surface Water Quality Engineering
1960-1970 (Computerization)• Problems: primary and secondary effluent• Pollutants: BOD• Systems: streams and estuaries (1D/2D)• Kinetics: linear, feed forward• Solutions: analytical and numerical
Modeling: Historical Development
(Chapra 1997) CE4505 – Surface Water Quality Engineering
1970-1977 (Biology)• Problems: eutrophication• Pollutants: nutrients• Systems: streams, lakes and estuaries
(1D/2D/3D)• Kinetics: nonlinear, feedback• Solutions: numerical
Modeling: Historical Development
(Chapra 1997) CE4505 – Surface Water Quality Engineering
1977- 2000 (Toxics)• Problems: toxics• Pollutants: organics, metals• Systems: sediment-water interactions
food chain interations, streams, lakes and estuaries
• Kinetics: linear, feed forward• Solutions: analytical
Modeling: Historical Development
(Chapra 1997) CE4505 – Surface Water Quality Engineering
2000 - present (Ecosytems)• Problems: ecosystem change, climate, invasives• Pollutants: natural components – carbon, nutrients, organisms• Systems: primary production, food web interactions• Kinetics: nonlinear, feedback• Solutions: numerical
Modeling: Historical Development
(Chapra 1997)
Benthic Invertebrates
Phytoplankton
Whitefish
CE4505 – Surface Water Quality Engineering
