St. Elizabeths West Campus 106 Consulting Meeting Agenda Utility Infrastructure Tunnels Direct Bury 1
HPASE 1 UTILITIES No Impact Trees: No precautions required Trees whose optimum tree protection zone, as defined by Matheny and Clark (1998) in Trees and Development, is not intersected by the Phase I Utility LOD and require no care. Potential Special Consideration Trees: Take precautions to minimize or eliminate impact Trees whose optimum tree protection zone, as defined by Matheny and Clark, is intersected by the Phase I Utility LOD; These trees are not necessarily going to be negatively impacted, but precautions should be taken due to the historical, cultural, environmental and horticultural significance of the trees. Potential Transplant Trees: Impacted dtrees that tcan be saved dthrough htransplant t Trees whose assumed location directly conflicts with the utility LOD, cannot be avoided and identified as a good candidate for transplanting. Lost Trees: Impacted trees that t can t be saved Trees whose assumed location directly conflicts with the utility LOD, cannot be avoided and not identified as a good candidate for transplanting. *All proposed tree care/ actions are dependent on an accurate survey, the locations used for this study originated from the Bartlett survey 2 Phase 1 Utilities - TERMINOLOGY
Notes: 1. Effects to each Contributing Feature are described with in the Cultural Resource Impacts Exhibit. 2. Contributing Features are per the Draft CLR/LPMP. 3. No Contractor parking or vehicle access outside of designated construction zone 4. Eagle Habitat to be protected according to US Fish and Wildlife Service Regulations. 5. Phase 1B Adaptive Reuse Limit of Disturbance included F1 1 C16 3 S14 F12 S14 S26 C3 T13b T32 W3 C12 T7 S14 S26 F8 T13e 2 Proposed Laydown S14 C16 C14 Proposed Laydown S21 S14 S22 C14 T26 C14 C14 C28 V9 Construction Perimeter (LOD) C16 Proposed Trailer Location Bald Eagle Protection Zone T6 S9 S8 Historic Sweetgum C16 LEGEND T22 4 NOC C25 Phase A C16 Historic A2 cemetery 5 Construction Zone/ LOD Temporary Fence Woodlands Bald Eagle Protection Zone Tree Canopy Outline of Tunnel Below C12 Contributing Features T6 Site Boundary Existing Buildings Proposed Buildings-NIC Existing Roads Proposed Access Road - NIC NORTH 3 Construction Laydown, & Staging Areas Building 52 included in Phase 1b MOA Proposed Roads-NIC Proposed Laydown Area
4 Phase 1 Utilities TUNNEL OPTION TREE IMPACTS
5 Phase 1 Utilities DIRECT BURY OPTION
- + 6 Phase 1 Utilities COMPARATIVE ANALYSIS TUNNEL & DIRECT BURY LOD
TUNNEL PROS: PERMANENT ACCESS FOR MAINTENANCE AND REPLACEMENT OF UTILITIES UTILITIES ARE STACKED ALLOWS FLEXIBILITY FOR MULTIPLE CONTRACTORS TO SEQUENCE THE WORK TUNNEL CONS: HIGHER UPFRONT COSTS REQUIRES SANITARY AND STORM LINES TO BE SHALLOW REQUIRING PUMP SYSTEMS DOES NOT ALLOW FOR MODIFIED CONSTRUCTION METHODS TO PRESERVE TREES DIRECT BURY PROS: FLEXIBILITY IN CONSTRUCTION METHODS ALLOWING THE PRESERVATION OF VEGETATION DOES NOT REQUIRE SHEETING AND SHORING (COSTS) ALLOWS FOR SANITARY AND STORM LINES TO GO DEEPER ALLOWING FOR GRAVITY DRAINAGE SYSTEMS DIRECT BURY CONS: REPLACEMENT OF UTILITIES REQUIRES REPLACEMENT OF ABOVE GRADE FEATURES (ROADS, SIDEWALKS ETC.) VISUAL INSPECTION OF UTILITIES IS NOT POSSIBLE CONTRACTOR COORDINATION ALL TRADES AT THE SAME TIME 7 TYPICAL SECTION TUNNEL VS. DIRECT BURY: PROS AND CONS
Close Monitoring by GSA Horticulturist, Landscape Architect and Arborist Root and/ or Canopy Pruning by Arborist Supplemental Irrigation During Construction Period Hand Excavation/ Air Spade Root/ Soil Protection (woodchips, gravel, geotextile, metal plates) Protection Matting Directional Boring Retaining Walls Discontinuous Footings/Grade Beams 8 Phase 1 Utilities TREE/SITE PROTECTION MEASURES
Close Monitoring by GSA Horticulturist, Landscape Architect and Arborist Root and/ or Canopy Pruning by Arborist Supplemental Irrigation During Construction Period Hand Excavation/ Air Spade Root/ Soil Protection (woodchips, gravel, geotextile, metal plates) Protection Matting Directional Boring Retaining Walls Discontinuous Footings/Grade Beams 9 Phase 1 Utilities TREE/SITE PROTECTION MEASURES
10 PRECEDENT LOANTAKA BROOK PRESERVE PIPELINE PROJECT
St. Elizabeths West Campus 106 Consulting Meeting 11 End