1. Ed Dunne, Ph.D, Division of Environmental Sciences, SJRWMD P.O. Box 1429, Palatka, FL 32178; Email: edunne@sjrwmd.com; ph: 386-329-4227edunne@sjrwmd.com A Case Study in Lake Management Issues

2.  Issues in lake management  Approach to lake restoration/enhancement  Lake Apopka and historical sketch  Time series of:  basin changes and nutrient loading  Nutrient budgets and water quality trends  Total P, Chl a, Transparency, TSS  Management practices  Within watershed, within lake  Lake Improvements  Accessing lake data  Water levels and water quality Overview

3. Water Management Districts in Florida

4. 18 Counties in the Districts

5. Ten Major Watersheds

6. Source:http://iaspub.epa.gov/waters10/attains_state.control?p_state=FL#total_assessed_waters Florida 2010 Lakes, Reservoirs, and Ponds 2010

7. Lakes, Reservoirs, and Ponds 2010: Causes of impairment Source: http://iaspub.epa.gov/waters10/attains_state.control?p_state=FL#total_assessed_waters

8. Multipronged approach to deal with impairment Restoration/Enhancement   Reduce nutrient load to the lake   Cost effective nutrient program to:   Remove   Reduce Source Control Within Watershed Mitigate Loss Within Lake

9. Controlling and Mitigating Eutrophication Reduce P loading Lower P concentration & plankton Increase water transparency Increase SAV Increase game fish Time Improved Ecosystem Health

10. Multipronged approach to lake improvement Lake water quality Water levels Restoring Wetlands Storm water Acquiring land TMDL Control of Hydrilla Planting littoral zone Marsh Flow-Way Shad Harvest Within Watershed Within Lake

11. Lake Apopka

12. A lake and it’s watershed

13. Lake Apopka Historical timeline: 1880s-2010s   1880s Land around the lake $0.25/acre   1890s Apopka Beauclair Canal   1920s Sewage, wastewater, hurricanes (6-8ft)   1940s Muck farms on NS, lake levee, hurricanes, blooms, < SAV   1950s Water control structures on ABC   1960s Fish kills, pesticide use by agriculture   1970s State/federal restoration, bacterial disease, bass failing, 4 fish camps   1980s Tower Chemical, fish kill, Apopka and SWIM Acts, no fish camps, pilot projects initiated, $15 million land purchase   1990s FOLA, MFW pilot project, shad harvest, Act ’96 (P criterion), $100 million land purchase, bird die off   2000s TMDL, MOU, MFW, reflooded 5,000 acres of NSRA   2010s Bird list = 346 sp., MFW, shad, BMAP projects, reflooded 10,000 acres, > SAV

14. Time series: Basin changes, P loading, and water quality

15. Sources: Lake Apopka External Nutrient Budget 1989-2002; Schelske et al., 2005. Basin Land Use Changes

16. Major Former Farm Areas Source: Lake Apopka External Nutrient Budget 1989-2010

17. Basin Land Use Changes

18. Phosphorus Loading to Lake Apopka 1900-2002 Measured Estimated from literature Loading g m -2 yr -1

19. Phosphorus Loading to Lake Apopka 1989-2010

20. Total Phosphorus (P) (mg/L)

22. Total P (metric tons) and Stage

23. Relationship between chl. a and total P

24. Chlorophyll a (µg/L)

26. Relationship between TSS and chl. a

27. Total Suspended Solids (mg/L)

29. Secchi depth (meters)

31. Some management practices to help improve the lake Within lake Within watershed

32. Reflooding Ag. lands back to Wetlands RESULTS  2000 Initial flooding of Duda Sub-East 680 acres  2011 Flooding to date about 10,000 acres Phased Approach  Environmental Site Assessments, Risk Assessment  BA, BO, biota monitoring during flooding  Prior to flooding:  Field prep., which included soil amendment (3,000 ha; $2.5 m)  Remediation to reduce OCP - deep ploughing (1,620 ha; $9.6 m)

33. 2000 Phased Approach to Flooding Maps produced by P. Bowen

34. 2005 Phased Approach to Flooding Maps produced by P. Bowen

35. 2010 Phased Approach to Flooding Maps produced by P. Bowen

36. 2011 Phased Approach to Flooding 9,870 acres flooded Maps produced by P. Bowen

37. Gizzard Shad Harvest on Lake Apopka 1993 - 2010 RESULTS  450-500 mT/yr of fish harvested  P removal in fish = 2-3 mT/yr GOALS  Remove P in fish bodies  Reduce recycling of P caused by bottom feeding  Reduce turbidity caused by bottom disturbance

38. Gizzard Shad Harvest on Lake Apopka 1993 - 2010

39. Marsh Flow-way 2003 - 2010 REMOVAL RESULTS  TP: 2 mT, 28%, 0.8 g m -2 yr -1  TSS: 4,000 mT, 91%, 1,300 g m -2 yr -1  TN: 80 mT, 22%, 26 g m -2 yr -1 GOALS  Maximize P removal from the lake  Provide wetland habitat

40. Total Phosphorus

41. Total Suspended Solids

42. Total Nitrogen

43. Evidence for Lake Improvement

44. PrePost Pre = period used to measure baseline loading for TMDL development (Magley, 2003) Post = period to include years with both normal and low lake stages Total Phosphorus (P) (mg/L)

45. Changes in Lake Apopka Concentrations & Loads ParameterUnitsComparison period Pre (‘89-’94) Post (‘03-’10) Change TP loading mT/yr6426-59% TP mg/L0.210.11-45% Chl a µg/L9963-37% Secchi m0.210.3356% TSS mg/L8667-22% TP mT4319-55% TSS mT17,53310,927-38% TN mT1,112715-36%

46. YearArea (acres) 19972.9 20006.2 20030 200613.6 20080 200913.5 201150 Changes in areal coverage of Vallisneria americana along Lake Apopka shoreline

47. Accessing lake data http://floridaswater.com/