1. Multi-Jurisdictional-Use Facilities Flow Analysis Study Update Presented to Blue Plains Regional Committee March 24, 2011 District of Columbia Water and Sewer Authority

2. Agenda  Original Purpose & Background  Review of Modeling Assumptions  What Changed? Strictly Flow Analysis Removed all prior agreements (except IMA) Improved as a Reference function  Cost Implications if adopted 2

3. Purpose & Background BACKGROUND: DC Water developing a method to allocate capital costs among multi-jurisdictional facility (MJUF) users that is proportional to the demands they place on the peak capacity of the facilities PURPOSE: To determine each user’s peak capacity as a percentage of the modeled flow capacity for each major MJUF 3

4. Approach Analyze multi-jurisdictional flow routes with the MIKE URBAN model used in developing the Long Term Control Plan for CSO Determine peak flow conditions using IMA Peak Transmission Limits for suburban users and modeled peak flows for the District Determine each User’s share of the peak flow, as peak flow rate and as percentage of the modeled peak flow rate, for each segment (node to node) of each MJUF 4

5. MIKE URBAN Model Assumptions  Suburban IMA peak flow allocations were introduced as a constant at the DC boundaries / upstream end of the MJUF  Within the District, modeled peak flows were incrementally added along the route as determined by the sewersheds for the MJUF  For District sanitary sewers – the model predicted peak hourly sanitary flows, base groundwater, I/I and private property stormwater allowances.  For District combined sewers – the model predicted stormwater runoff from a 15-year, 6-hour frequency design storm as well as peak hourly sanitary flows, groundwater and I/I allowances. 5

6. Flow Analysis Report Revisions  Report drafted as a flow analysis for the Users to assist for future capital cost allocations for MJUF CIP Removed funding considerations from past projects as a constraint  Flow analysis “constraints” limited to IMA allocations and firm pumping capacity of MJUF stations  District flows routed through WSSC and back to the District have been accounted for at the boundary conditions.  Known CIP projects that have or will alter MJUF peak flow in a known capacity have been included (UPI Rehab, etc.)  Increased reference information for ease of use 6

7. Potomac Interceptor (UPIRS) Assignment of Peaks to Users JurisdictionSum of Peaks in IMA (mgd) User share of IMA Total (%) User share of 151 mgd Design Peak (mgd) WSSC83.241.7%62.9 Fairfax81.240.6%61.4 LCSA31.916.0%24.1 Other PI Users3.51.8%2.6 Totals199.8100%151 IMA allocations total 199.8 mgd for Potomac Interceptor outside of the DC-MD boundary. Design basis for PI and model is 151 mgd at the DC-MD boundary. User %’s proportionate to IMA but volumes based on design basis. 7

8. Flow Splits ~ WSSC Route # DescriptionUser Flow Rate (mgd) Boundary / Upstream % Downstream % 1Little Falls Trunk20.865.6%55.1% 2Upper Potomac Interceptor23.3100%54.9% 3UPIRS (PI in DC)62.9 (note 1)41.6%41.0% 4Rock Creek Main Interceptor56.686.8%29.5% 5Potomac Force MainsFrom Route 329.8% 6B St / NJ AveFrom Route 429.5%5.9% 7East & West OutfallFrom Route 69.3% 8Anacostia Force Main18593.0%75.8% 9Watts Branch & AMI5.9100%12.4% 10UOX and LOX Sewers34.8100%72.7% 11East & West Outfall Relief SwrsFrom Rts 5 & 845.8% Note 1 – 151 mgd design flow apportioned based on IMA peak flow allowances 8

9. Flow Splits ~ Fairfax & LCSA Route # Fairfax Flow Route DescriptionUser Flow Rate (mgd) Boundary / Upstream % Downstream % 2Upper Potomac InterceptorFrom Route 30%13.4% 3UPIRS (PI in DC)85.0 (note 1)40.6%25.4% 5Potomac Force MainsFrom Route 318.5% 11East & West Outfall Relief SwrsFrom Rts 5 & 812.1% Note 1 – 151 mgd design flow apportioned based on IMA peak flow allowances; Fairfax Flow includes 23.6 mgd introduced from Chain Bridge Route # LCSA Flow Route DescriptionUser Flow Rate (mgd) Boundary / Upstream % Downstream % 2Upper Potomac InterceptorFrom Route 30%3.8% 3UPIRS (PI in DC)24.1 (note 1)16.0%7.2% 5Potomac Force MainsFrom Route 35.2% 11East & West Outfall Relief SwrsFrom Rts 5 & 83.4% 9

10. How Potomac PS affects MJUF analysis 10 Potomac PS Rock Creek PS Potomac Interceptor (UPIRS) Upper Potomac Interceptor (UPI) Little Falls Trunk Sewer Rock Creek Main Interceptor (RCMI) Chain Bridge Structure 35A To B St / NJ Ave Trunk Sewer To Potomac Force Mains

11. Rock Creek PS Differences in Flow Potomac Interceptor (UPIRS) Upper Potomac Interceptor (UPI) Little Falls Trunk Sewer Rock Creek Main Interceptor (RCMI) Chain Bridge Structure 35A To B St / NJ Ave Trunk Sewer To Potomac Force Mains Potomac PS 11 User9/10 Report 3/11 Report WSSC118.8 mgd137.1 mgd Fairfax73.4 mgd85.0 mgd LCSA31.8 mgd24.1 mgd Other PI7.16 mgd2.6 mgd DC228.8 mgd211.2 mgd Prior report constrained suburban flow at the Potomac Pump Station. Constraint was based on the Potomac Pump Station cost sharing agreement.

12. MJUF Pump Station Comparison Sept 2010 ReportWSSC (%)Fairfax (%)LCSA (%)Other PI Users (%) DC (%) Rock Creek PS36.2%12.7%6.7%1.5%42.9% Potomac PS25.8%16.0%6.9%1.6%49.7% Main & O PS6.6%00093.4% Poplar Pt PS13.1%00086.9% March 2011 Report WSSC (%)Fairfax (%)LCSA (%)Other PI Users (%) DC (%) Rock Creek PS58.3%13.0%3.6%0.4%24.7% Potomac PS29.8%18.5%5.2%0.6%45.9% Main & O PS9.3%00090.7% Poplar Pt PS13.1%00086.9% 12

13. CIP Implications of MJUF  Current CIP Projects with identified MJUF $395M  Future CIP Projects to be added from Facilities Plan with identified MJUF $144M  Summary does not include SLRP projects (locations prioritized based on site rankings) 13

14. Current CIP for Multi- Jurisdictional Analysis ProjectsCIP Budget ($M) Projects w/ Prior Agreements$ 87.2 M Projects w/ Construction Completed$ 2.7 M Projects in Construction$ 72.4 M BPIS Rehab Project$ 56.0 M Projects in Planning / Design$ 177.2 M Totals$ 395.0 M 14 $233 M

15. D201 – BPIS Rehab Flow Analysis Jurisdiction% Based on Sept 2010 Report Funding Based on Sept 2010 Report ($ M) % Based on March 2011 Report Funding Based on March 2011 Report ($ M) DC83.4%$46.7 M84.6%$47.4 M WSSC15.1%$8.5 M14.0%$7.8 M Fairfax0.94%$0.52 M1.1%$0.61 M LCSA0.41%$0.23 M0.31%$0.17 M Other PI Users 0.09%$0.05 M0.04%$0.02 M Totals100.0%$ 56.0 M100.0%$56.0 M $56.0 M is project total budget including design, cm and construction 15

16. Upcoming MJUF CIP – $177 M Jurisdiction% Based on Sept 2010 Report Funding Based on Sept 2010 Report ($ M) % Based on March 2011 Report Funding Based on March 2011 Report ($ M) DC66.9%$118.5 M65.3%$115.6 M WSSC29.3%$51.9 M31.5%$55.8 M Fairfax2.4%$4.3 M2.5%$4.4 M LCSA1.1%$1.9 M0.7%$1.2 M Other PI Users 0.24%$0.43 M0.08%$0.14 M Totals100.0%$ 177.1 M100.0%$177.1 M For the 10-year CIP, includes identified locations and budgets for MJUF projects in planning and design; not including PI 16

17. Next Steps  User review of revised Flow Analysis Tech Memo for acceptance as a reference  Develop SOP for cost allocations for MJUF CIP projects  Update User CIP cost allocations based on SOP 17