OUTLINE Definitions Examples of Landfills in the Valley Construction on Landfills Materials Placement in Landfills Developments on Landfills – why develop landfills ?? Concerns Associated with Development on Landfills Landfill Materials Investigation Remediation of Construction and Demolition (C&D) Landfills Example Projects

DEFINITIONS MSW Landfill C&D Materials Inert Debris Landfill

EXAMPLES OF LANDFILLS IN THE VALLEY C&D Landfills Mostly Along the Salt River, Aqua Fria, Gila River & Santa Cruz River Created Generally by Mining of Aggregates for Concrete, Asphalt, and Base Course Materials Pits Left Behind are Backfilled with MSW or C&D 24th St Vulcan Materials, 28th St ( Dean Thomas Property), Salt River Pima Maricopa Dobson Plant Tempe Market Place

EXAMPLES OF LANDFILLS IN THE VALLEY MSW Landfills Queen Creek Landfill 27th Ave Landfill Tempe Municipal Landfill Northwest Regional Landfill, and Others Inert Debris Landfills Salt River Materials Group Dobson Plant 28th Street Landfill 24th Street Landfill Cotton Lane Landfill Estrella Pit

MATERILAS PLACEMENT IN LANDFILLS No Compaction During C&D Disposals No Processing is Completed Creates Nesting of Large Particles Blind Spots around Odd Shaped Particles Organics MSW Decomposes, Develops Settlement, LFG & Leachate

MATERILAS PLACEMENT IN LANDFILLS

DEVELOPMENTS ON THE LANDFILLS Install Recreational Facilities Low Load Bearing Structures on Compacted MSW, e.g. Distribution Center Heavier Structures on MSW should be on Deep Foundations Industrial and Commercial Developments on C&D

CONCERNS ASSOCIATED WITH LANDFILL MATERIALS Large Settlement Uneven/Differential Settlements Unpredictable – No Model Available on Stability Compaction by Itself Biodegradation Piping, Internal Erosion and Raveling Gas (LFG) and Leachate Production, Accumulation & Contamination of Air and Ground Water Organics in C&D Takes Too Long to Decompose

LANDFILL MATERIAL INVESTIGATION

SOLUTIONS TO PROBLEMS FOR C&D LANDFILLS Deep Dynamic Compaction (DDC) for Inert Debris Landfills Compaction Grout Vibrofloatation (Not Common) Remove and Reconstruct w/ Engineered Fill/Debris

Deep Dynamic Compaction (DDC) Tempe Market Place

SOLUTIONS TO PROBLEMS FOR C&D LANDFILLS Deep Dynamic Compaction (DDC): Effective up to 30’-35’ 30-ton Load Drop from 80-90 feet Height, Multiple Times Imparts approx. 150 ton-ft/sq.ft. Equivalent to 150% of Standard Proctor Compaction up to 25 Foot Depth Evaluate Performance Can’t Take Care of all Piping and Raveling

2000 4000

Deep Dynamic Compaction

24th Street and Salt River– Vibration Monitoring

Performance Evaluation with Plate Load Test

SOLUTIONS TO PROBLEMS FOR C&D Debris Fill Specifications Anything as long as Inert Debris 2 to 3 feet Lift Thickness Compaction with 10 to 15 ton Equipment 3 to 4 Passes with 20 to 30 hertz vibration 30 to 60 Gallons/Cu.Yd. Water

Debris Fill Specifications

28th Street and Salt River 24th Street and Salt River EXAMPLE PROJECTS Tempe Market Place 28th Street and Salt River 24th Street and Salt River 14th Street and River View Drive

Tempe Market Place – Before Development

Tempe Market Place – During Stabilization

Tempe Market Place – After Development

24th Street & Salt River

CONCLUDING REMARKS Environmental Benefits Aesthetic Improvement Monetary Value Added Land Use Positive Economic Impact Catalyst Stops Illegal Dumping