DESIGN AND CONSTRUCTION OF AREA 7 CEDAR HILLS REGIONAL LANDFILL – Lessons Learned from Economic Conditions Mizanur Rahman, Ph.D., PE, PMP Senior Engineer and Project Manager King County Solid Waste Division 4/15/2011

Presentation Outline Overview of Cedar Hills Regional Landfill Area 7 Development Summary Pre-Design and Design Process Bidding Process Construction (Phase 1 and Phase 2) Lessons Learned Wrap-up/Questions 4/15/2011

Population served - 1.3 million; Landfill area: 920 acres of land Southeast King County Landfill operations began: Early 1960’s 850,000 tons/year; approx 1.13 MCY of airspace consumed/year Design capacity: 50-60 million tons Capacity consumed: 33 million tons as of 2010 Estimated closure date : 2024 4/15/2011

CEDAR HILLS REGIONAL LANDFILL SITE MAP 4/15/2011

Area 7 Development Overview Area Developed: 18.6 acres Design and CM budget: $2.9 million ; Construction: $10.01 million; King County Project Management : $254K Construction Contingency: $1.54 million Design Began: February 2006 and Construction Completed: March 2010 Construction completed in 2 phases: 2008 and 2009-10 4/15/2011

Area 7 Phase 1 Construction 4/15/2011

Area 7 Phase 2 Construction 4/15/2011

Area 7 Commissioned 4/15/2011

Area 7 Grand Opening 4/15/2011

Area 7 Development Timeline   2006 2007 2008 2009 2010 1 2 3 4 5 6 7 8 9 10 11 12 Pre-design (Initial Plan) Pre-Design (Actual) Detailed Design (Initial Plan) Detailed Design (Phase 1 & Phase 2) Bidding (Initial Plan ) Bidding (Phase 1 & Phase 2) Construction (Initial Plan) Construction (Phase 1 & Phase 2) Planned Actual 4/15/2011

King County Area 7 Development Budget Prepared in 2005 Based on escalating costs from 2003 bids Engineer’s cost estimates were based on the average unit bid price of Area 6 development projects. Cost estimates were prepared at 90% level only. 4/15/2011

Area 7 Phase 1 -2008 Construction Bid Summary Area 7 Partial Excavation (Schedule B)- 12 bid items 5 bids submitted Engineer’s Estimate : $2,044,244 (Excl. Tax and Contingency) Lowest Bidder: $2,375,842 Highest Bidder: $3,470,454 Contract Awarded for : $2,811,156 (37.52% higher than Engineer's Estimate) (Contract awarded to the bidder with lowest combined bid total for all schedules) 4/15/2011

Phase 1 Construction Bid Items (Quote Comparison) Major Bid Items % of Total Estimate Engineer's Unit Rate $/CY Bidder's Average Rate ($/CY) % change over Engineer's Rate Excavation and Haul to Main Stockpile 34.97% $2.00 $3.65 82.60% Processing for Select Fill Materials 23.70% $4.27 $4.00 -6.32% Select Fill Haul and Place in Area 5 Stockpile 9.24% $2.25 $4.35 93.33% Screen 2" to 6" rock and place in Main Stockpile 8.88% $4.99 24.75% Crush 6" Over, Screen and place in Main Stockpile 8.33% $6.00 $8.90 48.33% 4/15/2011

2009 Area 7 Phase 2 Design Modifications Initial Engineer’s Estimate: $9.68 millions Revised Engineers Estimate: $8.42 million Design Modified @90% design level for the following items: Reduce Drainage Layer Material (DLM) thickness from 24”to 18” Owner excavate as much of the Area as possible Eliminate the Contaminated Stormwater (CSW) Lagoon modifications Revise the Area 7 temporary in-cell CSW lagoon Use 60 mil HDPE geomembrane liner in lieu of 80 mil HDPE liner Remove 22” landfill gas (LFG) sub-header from the bid package 4/15/2011

2009 Area 7 Phase 2 Construction Area 7 Phase 2 Construction included: Remaining Excavation (394,000 cy) Liner System Construction Leachate collection Initial Landfill Gas Collection Stormwater management system Contaminated Stormwater lagoon Expansion 4/15/2011

2009 Area 7 Phase 2 Construction (contd.) Total 62 bid items 10 bids submitted Engineers Estimate: $8.38 million Lowest Bidder’s Quote: $5.55 million Highest Bidder’s Quote: $8.09 million Contract Awarded for : $5.62 million (32.94% Lower than Engineer's) (Contract awarded to the bidder with lowest combined bid total for all schedules) 4/15/2011

% Change over Engineer's Rate Materials Price Variation (Engineer’s Estimated Rate Vs. Bidder’s Rate) Bid Item Description % of Total Cost Engineer's Unit Price Bidders Avg. Rate % Change over Engineer's Rate Geotextile - Type 3 3.92% $2.91 $2.27 -21.95% 60 mil Textured HDPE Geomembrane 7.25% $5.38 $5.43 1.01% Geosynthetic Clay Liner (GCL) 5.90% $4.38 $5.74 31.02% HDPE pipes (6" to 24") 10.26% $26.67-$101.63 $20.36-$85.67 -16% to -40% 4/15/2011

Price Variation for Major Construction Items (Engineer’s Estimate Vs Price Variation for Major Construction Items (Engineer’s Estimate Vs. Bidder’s Rate) Item Description % of Total Cost Estimate Engineer's Unit Rate ($) Bidder's Avg. Rate ($) % Change over Engineer's Rate Crushed Surfacing Base Course 1.93% $22.76 $18.19 -20.06% Excavation and Haul 18.60% $3.28 $2.94 -10.43% Drainage Layer Material 22.43% $31.16 $25.01 -19.73% Select Fill Processing 3.17% $7.00 $7.47 6.75% LFG Connection 2.99% $5,470 $1,936 -64.60% LFG Sub-Header Riser Bank 4.78% $23,734 $3,092 -86.97% Grass Lined Ditches 0.77% $11.52 $6.68 -41.98% Asphalt Lined Ditch - Area 7 Perimeter 0.80% $27.58 $18.37 -33.41% 4/15/2011

Critical Bid Item for Phase 2 Construction Drainage Layer Material (DLM): 22.43% of the total quote Quote for DLM by Bidder (Contract Awarded): 39% lower than the engineers estimated rate The DLM bid item was not critically evaluated with respect to its specifications and market price An ambiguity in the DLM specification existed and was overlooked Differences in interpreting the DLM specification led to a claim by the Contractor 4/15/2011

Lessons Learned Changes in Economic Conditions had impacts on: Construction services pricing; Bid materials pricing; Competition; Quality control; and Schedule delay 4/15/2011

Lessons Learned (Contd.) Alternative engineering cost estimating technique is necessary and should include: Baseline (30% design level) cost estimate based on historical cost data of similar projects Update baseline cost estimate with design progression at (60%, 90%, and 100% level) Verify and update the cost estimate with market conditions 4/15/2011

Lessons Learned (Contd.) Benefits of alternative engineering cost estimating technique : Additional costs for design modification to meet the budget goals could have avoided/mitigated at earlier stage Critical bid items should be estimated more accurately Gap between final cost estimate and the budget could be minimized at earlier stage of the design plan. 4/15/2011

Lessons Learned (Contd.) Critical review of the bid items with high volume and high price tags during bid evaluation stage: Bid specifications of the critical bid items be evaluated for market conditions Bidder’s explanation on extremely low/high quoted items be sought at bid review session 4/15/2011

Lessons Learned (Contd.) Additional costs incurred for: Reworking design plans to comply with budget ($67,000) Preparing two bid packages ($175,000) Claim for DLM specifications Changes ($465,000) Support services for claim negotiation ($95,000) Extended construction management , ($ 70,000) and Extended county project management (Approx. $30,000). 4/15/2011

Conclusions Perform 30%-60%-90% design within budget limits Update cost estimate at 30%-60%-90% design level Prepare budgets based on escalating old cost data as well as market condition Engineer’s cost estimate should be updated and validated with market prices along with design progression Allow for design improvements during construction Use of mattress – an innovative technique for protecting DLM from soil clogging 4/15/2011

Area 7 Operations- Use of Mattress 4/15/2011

Questions??? Thank you! THANK YOU! mizanur.rahman@kingcounty.gov 4/15/2011

Area 7 Phase 2 Construction (Geomembrane Liner) Connection Between Area 6 and 7 Geomembrane Rolls Out on Area 7 4/15/2011 Extrusion Welding on Geomembrane Pipe Booting with Geomembrane

Manhole for Leachate Collection Initial Gas Pipeline Collector Installing Penetration Box 4/15/2011 Areas 5 and 7 Leachate Tie-in