1. Landfill Closure Issues

2. Stormwater Retention  Florida Regulations - –must collect and detain runoff from first 1” of rainfall (for > 100 acres, 0.5” for < 100 acres) –detain for 24 hrs.

3. Stormwater Control Direct surface water run-off away from the landfill

4. Stormwater Management

5. Monitoring  Leachate head within landfill  leakage through landfill liner (groundwater)  ambient air quality  gas  leachate quality  stability of final cover

6. Minimum Groundwater Monitoring One line of three (minimum) well down gradient from landfill perpendicular to groundwater flow, penetrating entire saturated thickness of aquifer (1/250 ft of landfill frontage at boundary of site or at surface water)

7. Minimum Groundwater Monitoring  One well immediately adjacent to downgradient edge of filled area at point where leachate plume meets GW. Screened to intercept water table  one well in area upgradient from landfill

8. Monitoring wells Landfill Groundwater Direction

9. Monitoring Wells Confining Unit Landfill Water Table

10. Closure  financial assurance criteria –estimate cost of closure/post closure care –demonstrate financial assurance cash irrevocable letter of credit trust funds with licensed trust company or state surety bonds

11. Final Cover – Water Movement

12. Final Cover Drainage Design Objective: To reduce pore water pressure, avoid seepage-induced instability and limit infiltration

13. Post closure  30 years  maintain integrity of cover  maintain LCS  monitor GW  maintain gas monitoring system

14. Thoughts on Post-Closure  30-years may not be the right time  Can one ever “walk away”?  Must have a risk based approach to end

15. The End of Post-closure Care  Regulatory-stipulate 30 years is arbitrary  No clearly defined process on how to exit post-closure care period