Investigation Area H1 Wetland Mitigation Activities Mare Island Restoration Advisory Board Meeting

1. Investigation Area H1Wetland Mitigation Activities Mare Island Restoration Advisory Board Meeting February 22, 2007 IA-H1 Wetland Mitigation Activities February 2007

2. Investigation Area H1 Location IA-H1 Wetland Mitigation Activities February 2007

3. Cleanup being undertaken by WESTON on behalf of the Navy through a grant to the City of Vallejo Objective is to isolate the waste from groundwater and eliminate contact with potential human and ecological receptors Interim remedy completed (2004) Slurry Wall and Groundwater Extraction System Final remedy in progress (2006 – 2007) Geomembrane/soil cap over former landfill areas (72 acres) Hot spot soil excavation and consolidation within cap area Soil cover within existing uplands area Wetland mitigation IA-H1 Cleanup Summary IA-H1 Wetland Mitigation Activities February 2007

4. Wetland Habitat Within IA-H1 Containment Area IA-H1 Wetland Mitigation Activities February 2007

5. Approximately 7.2 acres of isolated non-tidal wetland were present within the IA-H1 Containment Area 2.0 acres of pickleweed (salt marsh harvest mouse habitat) 0.5 acres of seasonal ponds (migratory bird habitat) 4.7 acres of degraded wetland habitat These wetlands are within or adjacent to waste disposal areas Wetlands will be impacted (filled) to allow construction of the engineered geomembrane cap IA-H1 Remedial Action Plan/Record of Decision approved in August 2006; USFWS Biological Opinion dated June 2006 IA-H1 Containment AreaWetland Status IA-H1 Wetland Mitigation Activities February 2007

6. Mitigation: “Replacing lost or adversely impacted habitat with habitat having similar functions of equal or greater ecological value” United States and California policy is no net loss of wetlands Regional Water Quality Control Board regulates discharge into waters of the State (e.g. wetlands) U.S. Fish and Wildlife Service and California Department of Fish and Game regulate potential impacts to listed endangered species (e.g. salt marsh harvest mouse) What is Mitigation & Why is it Required? IA-H1 Wetland Mitigation Activities February 2007

7. Create 8.2 acres of higher value wetland to replace 7.2 acres lost within Containment Area 6.7 acres pickleweed-dominated wetland to replace 2.0 acres of pickleweed wetland habitat 1.5 acres of seasonally ponded water to replace 0.5 acres of ponded wetland habitat Perform confirmation sampling after excavation to verify compliance with non-tidal wetland cleanup criteria Any exceedances require 3 feet of over-excavation and backfilling to grade with acceptable import soil Plant and seed with native species for pickleweed wetland area Provide 5-years minimum of monitoring to verify compliance with performance criteria IA-H1 Wetland Mitigation Requirements IA-H1 Wetland Mitigation Activities February 2007

8. IA-H1 Wetland Mitigation Areas(Shown in Blue Shading) IA-H1 Wetland Mitigation Activities February 2007

9. Close to impacted area Low-lying upland area requiring less excavation to lower elevation to create wetlands Anticipated to be not impacted or only marginally impacted from prior disposal activities Pre-selection sampling conducted Connect existing isolated pickleweed areas into a larger, contiguous pickleweed wetland Mitigation Area Location Rationale IA-H1 Wetland Mitigation Activities February 2007

10. Wetland Confirmation Sampling Grids IA-H1 Wetland Mitigation Activities February 2007

11. Wetlands EPA IX Residential PRGs Mercury 2 23 Cadmium 5.2 37 Lead 59 150 Chromium 140 210 Nickel 130 1,600 Zinc 230 23,000 Non-Tidal Wetland Metals Cleanup Criteria(mg/kg) IA-H1 Wetland Mitigation Activities February 2007

12. Educate workers Trap/relocate SMHM within Containment Area prior to impacting wetlands Completed July 2006 Trapped/passively relocated three SMHM Install exclusionary silt fence for work areas adjacent to SMHM habitat during excavation of new wetlands Provide periodic biological monitor for work adjacent to wetlands Salt Marsh Harvest Mouse Mitigation Measures IA-H1 Wetland Mitigation Activities February 2007

13. IA-H1 Salt Marsh Harvest Mouse IA-H1 Wetland Mitigation Activities February 2007

14. Uplands Excavation to Create Wetlands IA-H1 Wetland Mitigation Activities February 2007

15. Wetland Mitigation Area Planting IA-H1 Wetland Mitigation Activities February 2007

16. 14,701 plants Alkali Heath: 3,971 Salt Grass: 4,027 Pickleweed: 6,703 627 pounds seed Fat Hen: 150 lbs Alkali Heath: 70 lbs Pickleweed: 407 lbs Plant grown from cuttings collected on Mare Island in 2004, seeds also collected from Mare Island All plants installed in January/February 2007 7.1 acres of pickleweed wetland created vs 6.7 acre required Wetland Plant Species & Seed Quantities IA-H1 Wetland Mitigation Activities February 2007

17. Year 1: 10% coverage with native species Pickleweed, saltgrass, alkali heath Year 2: 25% coverage with native species Year 3: 45% coverage with native species, 30% pickleweed coverage Year 4: 65% coverage with native species Year 5: 90% coverage with native species, 60% pickleweed and < 5% non-native plants 1.5 acre ponded area: Exhibit saturation for a minimum of 14 consecutive days each year Wetland Creation Performance Criteria IA-H1 Wetland Mitigation Activities February 2007

18. Questions? IA-H1 Wetland Mitigation Activities February 2007