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Modeling Cyanobacteria Movement in Milford Lake, 

Part IIAuthors:

C. Bryan Young1, Ph.D., P.E.

Z. Charlie Zheng2, Ph.D.

Haidong Liu2, Ph.D.

Ted D. Harris3, Ph.D.

1University of Kansas, Department of Civil, Environmental and Architectural Engineering2University of Kansas, Department of Aerospace Engineering3University of Kansas, Kansas Biological Survey

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Background

• Research Funded by KDHE• Use computer modeling to develop a better understanding of cyanobacteria transport

• Develop animations for different scenarios, varying:• Lake Level

• Wind Conditions

• Flow Rate

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Model Description

• Research Model Developed at KU• 2D hydrodynamics

• Finite difference

• Rectangular, regular mesh

• Fully implicit

• Parallelized

• Constituent transport• Sediment

• Contaminant

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Background

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Background

• Two Projects• Phase 1: 2D model of algae transport in Milford Zone C

• 26 eight‐day simulations

• Project completed in 2017

• Phase 2: 2D model of algae transport in entire lake• 31 twenty‐day simulations

• Project completed in 2018

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Background

• Two Projects• Phase 1: 2D model of algae transport in Milford Zone C

• 26 eight‐day simulations

• Project completed in 2017

• Phase 2: 2D model of algae transport in entire lake• 31 twenty‐day simulations

• Project completed in 2018

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Phase 2 Simulations

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Days 1 ‐ 10 Days 11 ‐ 20 Beginning Days 1 ‐ 10 Days 11 ‐ 20

Wind Dir. Wind Speed Wind Dir. Wind Speed Lake Level Inflow Outflow Inflow Outflow

Case Bloom Location (from __) (mph) (from __) (mph) (ft) (cfs) (cfs) (cfs) (cfs)

1 1, 4, 5, 6 N 12 N 12 1138.4 25 25 2000 2000

2 1, 4, 5, 6 N 12 N 12 1141.4 25 25 2000 2000

3 1, 4, 5, 6 N 12 N 12 1144.4 25 25 2000 2000

4 1, 4, 5, 6 N 12 N 12 1146.4 25 25 2000 2000

5 1, 4, 5, 6 N 12 N 12 1141.4 25 25 25 25

6 1, 4, 5, 6 S 12 S 12 1138.4 25 25 2000 2000

7 1, 4, 5, 6 S 12 S 12 1141.4 25 25 2000 2000

8 1, 4, 5, 6 S 12 S 12 1144.4 25 25 2000 2000

9 1, 4, 5, 6 S 12 S 12 1146.4 25 25 2000 2000

10 1, 4, 5, 6 S 12 S 12 1141.4 25 25 25 25

11 1, 4, 5, 6 W 12 N 12 1138.4 25 25 2000 2000

12 1, 4, 5, 6 W 12 N 12 1141.4 25 25 2000 2000

13 1, 4, 5, 6 W 12 N 12 1144.4 25 25 2000 2000

14 1, 4, 5, 6 W 12 N 12 1146.4 25 25 2000 2000

15 1, 4, 5, 6 S 12 S 12 1138.4 25 25 25 2000

16 1, 4, 5, 6 S 12 S 12 1141.4 25 25 25 2000

17 1, 4, 5, 6 S 12 S 12 1144.4 25 25 25 2000

18 1, 4, 5, 6 S 12 S 12 1146.4 25 25 25 2000

19 1, 4, 5, 6 S 12 S 12 1141.4 100 100 100 100

20 1, 4, 5, 6 S 12 S 12 1141.4 500 500 500 500

21 1, 4, 5, 6 S 12 S 12 1141.4 1000 1000 1000 1000

22 1, 4, 5, 6 S 20 S 20 1141.4 1000 1000 1000 1000

23 1, 4, 5, 6 S 12 N 12 1444.4 25 25 25 25

24 1, 4, 5, 6 N 12 S 12 1444.4 25 25 25 25

25 1, 4, 5, 6 S 12 N 12 1444.4 25 25 2000 25

26 1, 4, 5, 6 S 12 N 12 1444.4 25 25 1000 25

27 1, 4, 5, 6 S 12 S 12 1444.4 25 25 2000 25

28 7, 8 N 12 N 12 1444.4 25 25 2000 2000

29 7, 8 E 12 E 12 1444.4 25 25 2000 2000

30 7, 8 S 12 S 12 1444.4 25 25 2000 2000

31 7, 8 W 12 W 12 1444.4 25 25 2000 2000

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Phase 2 Results

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Phase 2 Results

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Phase 2 Results

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Summary of Phase 2

• What it does do• Builds a qualitative understanding of algal transport in entire lake

• Evaluates a wide variety of wind and flow conditions

• Limitations• Simulation in 2D, not 3D

• Treats algae as a conservative tracer

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2D vs 3D

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2D vs 3D

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3D Model

• 3D hydrodynamics• Non‐hydrostatic simulation

• Vertical movements of algae

• Automated wet/dry cell detection 

• Parallelized high performance cluster computing 

• Algae growth and decay due to environment factors

• Algae transport (convection and diffusion

• Varying buoyancy

• Irradiation, nutrients, temperature, and salinity

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Comparison to the Environmental Fluid Dynamics Code (EFDC)

Pros:• the Virginia Institute of Marine Science (VIMS) and School of Marine

Science of the College of William and Mary, by Dr. John M. Hamrick.

• Multifunctional surface water modeling system

• Hydrodynamics, sediment, algae, and other contaminants

• Over 100 water bodies including rivers, lakes, reservoirs, wetlands, estuaries, and coastal ocean regions

• One of the most widely used and technically defensible hydrodynamic models in the world

Cons:• Hydrostatic assumption

• Constant vertical algae velocity

3D Hydrodynamic Validation: Oscillating Basin

Initial free surface elevation:0.1 cos

Casulli, V. (1999). “A semi-implicit finite difference method for non-hydrostatic, free-surface flows.” Int. J. Numer. Methods Fluids, 30(4), 425–440.

Initial Free Surface Elevation along X-axis

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3D Simulation of Milford Lake

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(Foster, et al. 2015)

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Comparison with Surface Measurement at F1(Liu, Zheng, Young, and Harris, Ecological  Modelling, 2018)

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• Wind effect (with varying speed and direction) may be dominant to cause Microcystis transport

• Wind induced mixing may cause Microcystis colonies to sink

• Wind diminished in the last 10 hours of the simulation, and a better agreement shows.    

Summary

• Phase 1 – Complete • Algal transport in Milford Lake, Zone C

• 26 scenarios, 82 total simulations

• Phase 2 – Complete • Algal transport in entire lake

• 31 scenarios, 116 total simulations

• 3D Model with Growth Dynamics Developed

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Questions?

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For more information, contact:

C. Bryan Young, Ph.D., P.E. (cbyoung@ku.edu) or

Z. Charlie Zheng, Ph.D. (zzheng@ku.edu)