1. CE5504 – Surface Water Quality Modeling CE5504 Surface Water Quality Modeling Lab 3. Modeling Loads – The C/Q Approach Applied to Onondaga Lake

2. Types of Loads CE5504 – Surface Water Quality Modeling load, mass · time -1, g · d -1 point source, tributaries: Q · C, m 3 ·d -1 x g·m -3 nonpoint terrestrial source: UAL·A, g·m 2 ·d -1 x m 2 nonpoint atmospheric source: J·A, g·m 2 ·d -1 x m 2 sediment source: J·A, g·m 2 ·d -1 x m 2 What is “A” for the last 3 cases?

3. Steady State C, Constant Loads and, at steady state, where W is constant and quantified as shown in the previous slide.

4. Time Variable C, Time Variable Loads applying numerical integration, how to describe W(t) ?

5. Time Variable C, Idealized, Time Variable Loads then an initial concentration is calculated, and the integration proceeds with W = 0 Impulse load (spill) 0

6. Time Variable C, Idealized, Time Variable Loads where an initial concentration corresponding to prior conditions is specified Step load (new continuous source)

7. Time Variable C, Idealized, Time Variable Loads where an initial concentration corresponding to prior conditions or W base is specified Linear load

8. Time Variable C, Idealized, Time Variable Loads where an initial concentration corresponding to prior conditions or W e is specified Exponential load

9. Time Variable C, Idealized, Time Variable Loads where an initial concentration corresponding to prior conditions or W bar is specified Sinusoidal load

10. Time Variable C, Flow-based Loads where Q and C are measured or specified Point Source Nonpoint Source where Q(t) is measured or specified and C is determined as f (Q), the “C/Q Plot”

11. C/Q for TSS in Ontonagon River, Lake Superior CE5504 – Surface Water Quality Modeling linear bipartite ascending - descending

12. C/Q for Chloride in Nine Mile Creek, Onondaga Lake CE5504 – Surface Water Quality Modeling inverse linear plot two different historical intervals

13. C/Q for TSS in Onondaga Creek, Onondaga Lake CE5504 – Surface Water Quality Modeling logC plot

14. C/Q for Total Phosphorus in Onondaga Creek, Onondaga Lake CE5504 – Surface Water Quality Modeling log – log plot two different stations

15. Little loads, like those from toads, Grow bigger when from horses. And on through us, I fear they must, Foul the water courses. Ode to the Load