1. EFFECT OF ORGANIC MATTER ON WAVE- INDUCED RESUSPENSION OF FINE SEDIMENT

2. Newnans Lake

3. Fine sediment aggregate constituents Clay mineral Non-clay mineral Wood fragmentWorm tube Biopolymer Pore water Diatom

4. N 0 100 km Gulf of Mexico Atlantic Ocean Cedar/Ortega Rivers Rodman Reservoir Newnans Lake Lower Kissimmee River Basin Lake Okeechobee Lake Bonnet Loxahatchee River Florida Extended Agricultural Area

5. Variation of wet bulk density with organic content Organic content, OC (%) Bulk density,  (kg m -3 ) 10 0 2030405060708090 1000 1500 2000 2500  = 1136exp(-0.32OC)-0.9OC+1110 Rodman Reservoir (Mehta et al., 1994) Lower Kissimmee River (Rodriguez et al., 1997) Loxahatchee River (Ganju, 2001) Cedar/Ortega River (Mehta et al., 2000; Gowland, 2002a) Lake Bonnet (Gowland, 2001) Newnans Lake (Gowland, 2002b)

6. Variation of dry density with organic content; data from six sites Organic content, OC (%) Dry density,  D (kg m -3 ) 100 20 30 4050 60 70 8090 500 1000 1500 2000 0 Rodman Reservoir Lower Kissimmee River Loxahatchee River Cedar/Ortega River Lake Bonnet Newnans Lake  D = 1900exp(-0.156OC) + 80

7. Variation of free settling velocity with organic content Organic content, OC (%) Settling velocity, w 0 (m /s) 1020304050607080900 10 -7 10 -6 10 -5 10 -4

8. Wind Induced Wave Sediment Re-suspension

9. NEWNANS LAKE

10. Shannon-Brezonik Trophic State Index (TSI): T = turbidity (JTU), CD = conductivity [(μΩ) -1 /cm =μS/cm], TN = total organic nitrogen (mg/l), TP = total phosphate (mg/l), PP = primary productivity (mg-C/m 2 -hr), CL = chlorophyll-a (mg/m 3 ) cation ratio CR = [Ca ++ ]+[Mg ++ ]/[Na + ]+[K + ]. TSI: 0-3 oligotrophic, 3-7 mesotrophic, 7-10 eutrophic, 10 hypereutrophic Newnans Lake = 15.3

11. Newnans Lake zones based on bathymetry. Suspended sediment concentration was measured at Sites A and B Outer open water area Inner open water area Exposed area 1 km N -1.5 m -0.5 m -0.3 m 0.0 m Site B Site A

12. Stage variation in Newnans Lake, 1995-2001 Date (y) Stage (m NGVD) February 1998 El Niño high Typical 1995-98 level August 2001 low 1.1 m 1995199619971998199920002001 19 20 21

13. Wind Record

14. Wind speed (m/s) Wave amplitude, a (m) Wave period, T (s) Peak wave- induced velocity, u m (m/s) 80.101.850.11 90.101.900.12 100.112.000.14

15. Bulk density,  (kg m -3 ) -1.4 -1.2 -0.8 -0.6 -0.4 -0.2 0.0 Depth below bed surface (m) 1030 10401050 1060 10701080 10 y 20 y 30 y 40 y 50 y 60 y 70 y 80 y Initial Density profile Brenner and Whitmore (1998) Gowland (2002) Bed surface Bed density variation due to consolidation and data from Newnans Lake

16. Erosion flux versus bed shear stress with lines of constant OC; data from Newnans Lake Shear stress, b (Pa) 0 0.1 0.2 0.3 00.050.10.150.20.250.3 OC (%) 60 50 40 30 20 10 Erosion flux,  (kg m -2 s -1 )

17. Settling velocity variation with concentration for Newnans Lake sediment

18. Concentration Profiles at Sites A in Newnans Lake 0.05 0.10 0.15 0.20 0.25 0.00 00.51.01.5 Elevation, z (m) Lutocline 30 min 60 min 90 min Data Concentration, c (kg m -3 )

19. Concentration profiles at Sites B in Newnans Lake Lutocline 0.05 0.10 0.15 0.20 0.00 0123 Elevation, z (m) Concentration, c (kg m -3 ) 30 min 60 min 90 min Data 4 120 min 0.25 0.30

20. Wind-induced re-suspension simulation in Newnans Lake 0 200400 0 2 1 3 100300 Time, t (min) Concentration, c m (kg m -3 ) 8 m s -1 9 m s -1 7 m s -1

21. Accelerometer Pore pressure sensor