1. Briefing on IMA Negotiation Issues Presented to: Blue Plains IMA Negotiating Team Operating Agency Work Group March 11, 2010 District of Columbia Water and Sewer Authority 1

2. 2 Items to be Resolved  O&M Cost  Joint use CSO facilities  CSO tunnels  Portions of Blue Pains Tunnel & Tunnel Dewatering Pumping Station  TN Facilities  Enhanced Clarification Facility (ECF)  Blue Plains Tunnel  Flow Allocation  Does captured combined sewage count against D.C. flow allocation?  Assessment of flows for comparison against allocations

3. 3 Sewer/Treatment System Overview Potomac Tunnel ECF Jurisdictional Meters Sewer system BP Complete Treatment Piney Br. Tunnel Anacostia & Blue Plains Tunnel DC Line TDPS 001 002 RWWPS DC Peak flow reduction diversions to tunnel Volume Flow Rate Information Sources It is not possible to explicitly meter how much of each jurisdictions flow ends up in each treatment system (complete treatment vs ECF)

4. 4 Agreed Capital Cost Allocation Complete Treatment Enhanced Clarification Facility Sewer System 1076 mgd 521 mgd Tunnel Dewatering Pumping Station 225 mgd total 31 mg added for ENR Outfall 002 Outfall 001 126 mg for CSO 170 mgd for CSO (7.1% suburbs per LTCP split) 55 mgd added for ENR (60% suburbs per IMA 370 split) 225 mgd Not needed for CSO Needed for ENR 555 mgd 157 mg total tunnel storage Bolling Diversion Str. Centrate Treatment New TN facilities Blue Plains Tunnel 73 mg Anacostia River & Northeast Boundary Tunnels - 84 mg 42 mg (60% suburbs per IMA 370 split) 126 mg for CSO (7.1% suburbs per LTCP split)

5. 5 O&M Cost for Joint Use CSO Facilities  Joint use CSO facilities:  Anacostia, Northeast Boundary, Potomac & Piney Branch Storage Tunnels  42/73 of Blue Plains Tunnel (CSO portion)  170/225 of Tunnel Dewatering Pumping Station (CSO Portion)  Other appurtenant CSO facilities (enumerated during CAO negotiation)  Past practice: base cost on actual measured volume entering tunnel for each jurisdiction  It’s not possible to measure volume by jurisdiction for DC or suburbs because flows are mixed AltDescriptionRationaleConsiderations 1 Model it every yearAccounts for year to year variations Costly & burdensome Significant year to year variations 2 Use average year (7.1%) 7.1% is “difference in Annual Volume Exceeding Treatment Capacity in Average Year (Annual CSO Overflow Volume)” This is volume in tunnels Simple Year to year variations will be incorrect, but overall average will be correct Additional item to be addressed: How will suburbs split up the 7.1 % of CSO costs – based on 370 mgd? Est. O &M approx $6 M/yr

6. 6 CSO Projects Determined to Be Joint Use During CAO Negotiations

7. 7 O&M Cost for New TN Facilities  New TN Facilities:  Enhanced Clarification  55/225 of Tunnel Dewatering Pumping Station  31/73 of Blue Plains Tunnel  Bolling Diversion Structure

8. 8 O&M Cost for New TN Facilities AltDescriptionRationaleConsiderations Calc based on ECF O&M = $2.3M/avg yr 1 Base on total volume delivered to Blue Plains All of ECF pollutant removal, storage & pumping is required for TN removal Suburbs = jurisdictional meter volume DC = (001+002) minus suburban volume Consistent with why facilities are being built (CAO negotiation) Simple Suburban = 60% x $2.3M = $1.4M DC = 0.4*$2.3 = $0.9M 2 Use model to estimate how much of treated volume thru ECF is: Due to peak reduction Due to CSO Estimate about 50% of volume thru ECF is due to peak flow reduction in avg yr Ignores pollutant removal provided by ECF – the basis for approval of TN plan Costly & burdensome 50% of cost ($1.15M) due to peak flow reduction Suburban cost = 60% x $1.15M = $0.7M 50% of cost is due to CSO Suburban cost = 7.1% x $1.15M = 0.08M Tot. Suburban Cost = $0.78M DC Cost = $1.52M 3Measure it Use jurisdictional meters to calculate volume of flow in a year which is between 1.5 peaking factor and 2.0 peaking factor Install flow meters at two major diversions to tunnel where peak reduction to BP will occur. Measure total volume into tunnel due to peak reduction. DC Volume = Total Volume – Suburban Volume Ignores pollutant removal provided by ECF – the basis for approval of TN plan Ignores flow routing of suburban flows (just because suburban flow exceeded 1.5 peaking factor doesn’t mean it ended up in tunnel)

9. 9 Does Captured Combined Sewage count against DC’s Flow Allocation? AltDescriptionRationaleConsiderations 1 Captured Combined Sewage counts against D.C’s allocationPlant is treating the flow Simple Ignores design basis for plant 2 Captured Combined Sewage does not count against D.C’s allocation Plant is required to maximize treatment No additional facilities were built to treat captured wet weather flow per Blue Plains Feasibility Study Use nomograph generated from model to estimate captured combined sewage once per year Subtract captured combined sewage from total influent flow when calculating DC’s annual average flow

10. 10 Example Captured Combined Sewage Nomograph Currently estimate about 15 mgd of captured combined sewage is treated at Blue Plains in an average year. Estimate this will increase to 21 mgd after LTCP in place (net increase of 6 mgd)

11. 11 D.C. Flows from 1999-2009 With and without Captured Combined Sewage

12. Impact of Captured Combined Sewage (CCS) on Allocation in Average Year (Estimated for Discussion Purposes with Regard to Offloading) 1.Assumes D.C. flows remain at 133 mgd, excluding captured combined sewage 2.Actual total D.C. flows from 2005-2009 have averaged 143.9 mgd (including captured combined sewage) 12

13. 13 Evaluation of Flows for Comparison Against Allocations in IMA AltDescriptionRationaleConsiderations 1 Base allocation on 001 + 002 Volume Suburban Flow = measured by jurisdictional meters DC Flow = 001+002 flow minus Suburban Flow minus Captured Combined Sewage Simple Allocation is based on 370 mgd in 002. No jurisdiction is specifically allocated flow in 001. Outfall 001 is the safety valve for the system. All jurisdictions use Outfall 001 to accommodate wet weather flows to the degree necessary. Add language to flow management sections of IMA requiring stewardship of plant capacity regarding control of infiltration and inflow

14. 14 Example Calculation – Average Year  002 Flow = 368.7 mgd  001 Flow = 7.3 mgd  Total flow = 376 mgd  Suburban meters = 222 mgd  DC flow = 376-222 = 154 mgd  Subtract captured combined sewage for D.C. allocation comparison:  154 – 21 = 133 mgd DC flow

15. 15 Example Calculation – Very Wet Year (60” rain, based on 2003, extra 65 mgd of I/I in system)  002 Flow = 435 mgd  001 Flow = 17.4 mgd  Total flow = 452 mgd  Suburban meters = 261 (222 + 60% x 65 mgd I/I)  DC flow = 452-261 = 191 mgd  Subtract captured combined sewage for D.C. allocation comparison:  191 – 25 mgd = 160 mgd DC flow (close to 133 + 40% x 65 mgd I/I)

16. 16 Impact of 2003 (60” Rain) on Jurisdictional Flows

17. 17 Summary of Recommendations No.IssueRecommendation 1 O&M cost of Joint Use CSO Facilities CSO Tunnels Portions of Blue Plains Tunnel and Tunnel Dewatering PS 2 O&M cost of TN facilities ECF 31 mg of Blue Plains Tunnel 3 Does Captured Combined sewage count against D.C. flow allocation? 4 Evaluation of Flows for Comparison against Allocations in IMA Suburban flow = from jurisdictional meters DC flow = (001+002) – Suburban flow- Captured Combined Sewage Allocate based on 370 mgd No jurisdiction is specifically allocated flow in 001. Outfall 001 is the safety valve for the system. All jurisdictions use Outfall 001 to accommodate wet weather flows to the degree necessary.